Version bump for release 3.0.2.

CHANGELOG.md

@@ -1,5 +1,19 @@
 # Change Log
 
+## 3.0.2 (2016-08-18)
+
+Features:
+
+* unified translation format for SAS and PDDL files
+* documentation of `plasp`’s output format
+* improved output syntax highlighting
+* uses ASP string literals to avoid escaping PDDL identifiers
+
+Bug Fixes:
+
+* fixes minor formatting issues in SAS translation
+* fixes issue with unsupported expression negations
+
 ## 3.0.1 (2016-06-14)
 
 Features:

CMakeLists.txt

@@ -7,7 +7,7 @@ set(CMAKE_CXX_FLAGS "-Wall -Wextra -Wpedantic")
 set(CMAKE_CXX_FLAGS_DEBUG "-g")
 add_definitions(-std=c++14)
 
-option(BUILD_TESTS "Build unit tests" ON)
+option(BUILD_TESTS "Build unit tests" OFF)
 
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)

README.md

@@ -6,8 +6,8 @@
 
 `plasp` 3 is in early development and not intended for productive use yet.
 
-`plasp` 3 translates planning problem instances to ASP facts.
-`plasp` 3 supports the input languages [PDDL](https://helios.hud.ac.uk/scommv/IPC-14/software.html) (only basic features currently) and the [SAS](http://www.fast-downward.org/TranslatorOutputFormat) (full support of the current version 3), which is used by [Fast Downward](http://www.fast-downward.org/).
+`plasp` translates planning problem instances to ASP facts.
+`plasp` 3 supports the input languages [PDDL 3.1](https://helios.hud.ac.uk/scommv/IPC-14/software.html) (only basic features currently) and [SAS](http://www.fast-downward.org/TranslatorOutputFormat) (full support of SAS 3), which is used by [Fast Downward](http://www.fast-downward.org/).
 
 Please get in touch with [Patrick Lühne](https://www.luehne.de) if you have any suggestions.
 
@@ -24,7 +24,7 @@ $ plasp domain.pddl problem.pddl
 Alternatively, PDDL instances may first be translated to SAS, the output format of [Fast Downward](http://www.fast-downward.org/).
 
 ```bash
-$ ./fast-downward.py --translate --build=release64 domain.pddl instance.pddl
+$ ./fast-downward.py --translate --build=release64 domain.pddl problem.pddl
 ```
 
 This creates a file called `output.sas`, which may now be translated by `plasp`.
@@ -42,51 +42,29 @@ $ plasp domain.pddl problem.pddl > instance.lp
 $ clingo encodings/pddl-meta-sequential-incremental.lp instance.lp
 ```
 
-### Command-Line Interface
+## Command-Line Interface
 
 ```bash
 $ plasp [files] [options]
 ```
 
-`[files]` may be omitted, in which case the input is read from `std::cin`.
-The `[options]` are listed below:
+`plasp` automatically detects the language of the input program.
 
-| **option**                        | **explanation**                                                                                                                   |
-|-----------------------------------|-----------------------------------------------------------------------------------------------------------------------------------|
-| `-l` [ `--language` ]             | Specify the input language (`sas` or `pddl`). Omit for automatic detection.                                                       |
-| `--warning-level` arg (=`normal`) | Specify whether to output warnings normally (`normal`), to treat them as critical errors (`error`), or to ignore them (`ignore`). |
-| `--color` arg (=`auto`)           | Specify whether to colorize the output (`always`, `never`, or `auto`).                                                            |
+See [command-line interface](doc/command-line-interface.md) for more details.
+
+## Output Format
+
+`plasp` provides a uniform output format for SAS and PDDL input problems.
+
+See [output format](doc/output-format.md) for more details.
+
+If you want to write your own meta encoding for `plasp`’s output, this [simple example encoding](encodings/sequential-incremental.lp) gets you started.
 
 ## Building
 
-`plasp` requires a C++14 compiler (preferrably GCC ≥ 6.1 or clang ≥ 3.8), the `boost` libraries (≥ 1.55), and CMake for building.
+`plasp` requires `boost` and is built via CMake and a C++ compiler.
 
-```bash
-$ git clone https://github.com/potassco/plasp.git
-$ cd plasp
-$ mkdir -p build/release
-$ cd build/release
-$ cmake ../.. -DCMAKE_BUILD_TYPE=Release
-$ make
-```
-
-The built `plasp` binary is then located at `plasp/build/release/bin/plasp`.
-
-### Running the Tests
-
-`plasp` provides unit tests written using the [Google Test](https://github.com/google/googletest) framework.
-Before building and running the tests, make sure you have fetched the Google Test git submodule:
-
-```bash
-$ git submodule init
-$ git submodule update
-```
-
-Afterward, build and run the tests as follows:
-
-```bash
-$ make run-tests
-```
+See [building instructions](doc/building-instructions.md) for more details.
 
 ## Contributors
 

apps/plasp-app/main.cpp

@@ -66,7 +66,7 @@ int main(int argc, char **argv)
 
 	if (variablesMap.count("version"))
 	{
-		std::cout << "plasp version 3.0.1" << std::endl;
+		std::cout << "plasp version 3.0.2" << std::endl;
 		return EXIT_SUCCESS;
 	}
 
@@ -104,9 +104,7 @@ int main(int argc, char **argv)
 
 	try
 	{
-		plasp::utils::Parser parser;
-
-		parser.setCaseSensitive(false);
+		plasp::utils::Parser<plasp::utils::CaseInsensitiveParserPolicy> parser;
 
 		if (variablesMap.count("input"))
 		{
@@ -115,11 +113,11 @@ int main(int argc, char **argv)
 			std::for_each(inputFiles.cbegin(), inputFiles.cend(),
 				[&](const auto &inputFile)
 				{
-					parser.readFile(inputFile);
+					parser.read(inputFile);
 				});
 		}
 		else
-			parser.readStream("std::cin", std::cin);
+			parser.read("std::cin", std::cin);
 
 		const auto detectLanguage =
 			[&]()

doc/building-instructions.md

@@ -0,0 +1,41 @@
+# Building Instructions
+
+`plasp` requires a C++14 compiler (preferrably GCC ≥ 6.1 or clang ≥ 3.8), the `boost` libraries (≥ 1.55), and CMake for building.
+
+```bash
+$ git clone https://github.com/potassco/plasp.git
+$ cd plasp
+$ mkdir -p build/release
+$ cd build/release
+$ cmake ../.. -DCMAKE_BUILD_TYPE=Release
+$ make
+```
+
+The built `plasp` binary is then located at `plasp/build/release/bin/plasp`.
+
+To update `plasp` to the most recent version, perform the following steps:
+
+```bash
+$ cd plasp
+$ git pull
+$ cd build/release
+$ cmake .
+$ make
+```
+
+## Running the Tests
+
+`plasp` provides unit tests written using the [Google Test](https://github.com/google/googletest) framework.
+Before building and running the tests, make sure you have fetched the Google Test git submodule:
+
+```bash
+$ git submodule init
+$ git submodule update
+```
+
+Afterward, enable the flag `BUILD_TESTS` in your CMake configuration.
+Finally, build and run the tests as follows:
+
+```bash
+$ make run-tests
+```

doc/command-line-interface.md

@@ -0,0 +1,18 @@
+# Command-Line Interface
+
+```bash
+$ plasp [files] [options]
+```
+
+`plasp` automatically detects the language of the input files.
+
+Multiple files may be provided in an arbitrary order.
+`[files]` may also be omitted, in which case the input is read from `std::cin`.
+
+`plasp` supports the following options:
+
+| **option**                        | **explanation**                                                                                                                   |
+|-----------------------------------|-----------------------------------------------------------------------------------------------------------------------------------|
+| `-l` [ `--language` ]             | Specify the input language (`sas` or `pddl`). Omit for automatic detection.                                                       |
+| `--warning-level` arg (=`normal`) | Specify whether to output warnings normally (`normal`), to treat them as critical errors (`error`), or to ignore them (`ignore`). |
+| `--color` arg (=`auto`)           | Specify whether to colorize the output (`always`, `never`, or `auto`).                                                            |

doc/feature-requirements.md

@@ -0,0 +1,22 @@
+# Feature Requirements
+
+Feature requirements are part of `plasp`’s [output format](output-format.md).
+Currently, `plasp` detects feature requirements only for SAS problems.
+
+`plasp` supports the following feature requirements:
+
+SAS feature | description
+------------|------------
+`actionCosts` | actions have associated costs (see [action costs](output-format.md#action-costs))
+`axiomRules` | immediate actions are used, which are executed as soon as the preconditions are satisfied (see [axiom rules](output-format.md#axiom-rules))
+`conditionalEffects` | some effects of an action may have additional conditions (see [actions](output-format.md#actions))
+
+## Example
+
+The following specifies that the input problem has the two requirements `actionCosts` and `conditionalEffects`.
+
+```prolog
+% requirements
+requiresFeature(actionCosts).
+requiresFeature(conditionalEffects).
+```

doc/output-format.md

@@ -0,0 +1,209 @@
+# Output Format
+
+`plasp` 3 translates SAS and PDDL files into a uniform ASP fact format.
+
+## Overview
+
+Essentially, `plasp`’s output format consists of [state variables](#variables) that are modified by [actions](#actions) if their preconditions are fulfilled.
+Variables reference [entities](#constants-objects) that are affected by the actions.
+As with PDDL, the objective is to achieve a specific [goal](#goal) starting from an [initial state](#initial-state) by executing a sequence of actions.
+
+`plasp`’s variables correspond to the multivalued variables in SAS.
+PDDL predicates are turned into Boolean variables to make the output format consistent.
+
+Actions are modeled exactly as PDDL actions and SAS operators.
+
+## In a Nutshell
+
+The following illustrates `plasp`’s output format for the problem of turning switches on and off.
+
+```prolog
+% declares the type "type(switch)"
+type(type(switch)).
+
+% introduces a switch "constant(a)"
+constant(constant(a)).
+has(constant(a), type(switch)).
+
+% declares a variable "variable(on(X))" for switches X
+variable(variable(on(X))) :- has(X, type(switch)).
+
+% the variable may be true or false
+contains(variable(on(X)), value(on(X)), true)) :- has(X, type(switch)).
+contains(variable(on(X)), value(on(X)), false)) :- has(X, type(switch)).
+
+% declares the action "action(turnOn(X))", which requires switch X to be off and then turns it on
+action(action(turnOn(X))) :- has(X, type(switch)).
+precondition(action(turnOn(X)), variable(on(X)), value(on(X), false)) :- has(X, type(switch)).
+postcondition(action(turnOn(X)), effect(0), variable(on(X)), value(on(X), true)) :- has(X, type(switch)).
+
+% initially, the switch is off
+initialState(variable(on(constant(a))), value(on(constant(a)), false)).
+
+% in the end, the switch should be on
+goal(variable(on(constant(a))), value(on(constant(a)), true)).
+```
+
+## Syntax and Semantics
+
+`plasp` structures the translated ASP facts into multiple sections, which are explained in the following.
+
+### Feature Requirements
+
+```prolog
+% declares a required feature
+requires(feature(<name>)).
+```
+
+`plasp` recognizes and declares advanced features used by the input problem, such as conditional effects, [mutex groups](#mutex-groups) and [axiom rules](#axiom-rules) (currently only SAS).
+See the [full list of supported features](feature-requirements.md) for more information.
+
+The feature requirement predicates may be used in meta encodings to warn about unsupported features.
+
+### Types
+
+```prolog
+% declares a <type>
+type(type(<name>)).
+
+% specifies that <type 1> inherits <type 2>
+inherits(type(<type 1>), type(<type 2>)).
+
+% specifies <constant> to be of type type(<name>)
+has(<constant>, type(<name>)).
+```
+
+[Variables](#variables), [constants](#constants-objects), and [objects](#constants-objects) may be typed. Types are only available with PDDL and if typing is enabled.
+
+`plasp` automatically generates all matching `has` predicates for objects with types that inherit other types.
+
+### Variables
+
+```prolog
+% declares a <variable>
+variable(variable(<name>)).
+
+% adds a <value> to the domain of a <variable>
+contains(<variable>, <value>).
+```
+
+`plasp`’s variables represent the current state of the planning problem.
+Variables are linked to the problem's [objects](#constants-objects) and [constants](#constants-objects).
+
+`plasp`’s variables are multivalued, and each variable has exactly one value at each point in time.
+
+With SAS, variable names are numbers starting at 0, `variable(<number>)`.
+SAS variables are inherently multivalued, which results in two or more values of the form `value(<SAS predicate>, <bool>)` for each variable.
+
+With PDDL, Boolean variables are created from the PDDL predicates.
+Variables ared named after the PDDL predicates, `variable(<PDDL predicate>).`
+Each variable contains exactly two values (one `true`, one `false`) of the form `value(<PDDL predicate>, <bool>)`.
+Note that with PDDL, variables and values are named identically.
+
+### Actions
+
+```prolog
+% declares an <action>
+action(action(<name>)).
+
+% defines that as a precondition to <action>, <variable> must have value <value>
+precondition(<action>, <variable>, <value>).
+
+% defines that after applying <action>, <variable> is assigned <value>
+postcondition(<action>, effect(<number>), <variable>, <value>).
+
+% defines the condition of a conditional effect
+precondition(effect(<number>), <variable>, <value>).
+
+% specifies the costs of applying <action>
+costs(<action>, <number>).
+```
+
+Actions may require certain variables to have specific values in order to be executed.
+After applying an action, variables get new values according to the action's postconditions.
+
+Actions may have *conditional effects*, that is, certain postconditions are only applied if additional conditions are satisfied.
+For this reason, each conditional effect is uniquely identified with a predicate `effect(<number>)` as the second argument of the `postcondition` facts.
+The conditions of conditional effects are given by additional `precondition` facts that take the respective `effect(<number>)` predicates as the first argument.
+
+Unconditional effects are identified with `effect(unconditional)`.
+
+Conditional effects are currently only supported with SAS input problems.
+
+Actions may also have *action costs* required to apply them. Action costs are currently supported for SAS only.
+
+### Constants/Objects
+
+```prolog
+% declares a <constant> or object
+constant(constant(<name>)).
+
+% specifies <constant> to be of type type(<name>)
+has(<constant>, <type>).
+```
+
+Constants and objects are the entities that are affected by [actions](#actions), for instance, the blocks in a Blocks World problem.
+Constants are global for a domain, while objects are problem-specific.
+
+`plasp` does not distinguish between the two (modeling both as constants), as both are identically used static identifiers.
+
+### Initial State
+
+```prolog
+% initializes <variable> with a specific <value>
+initialState(<variable>, <value>).
+```
+
+The initial state contains all [variable](#variables) assignments that hold before executing any [actions](#actions).
+
+Note that with PDDL, `plasp` sets all unspecified initial state variables to `false` in order to make the initial state total.
+
+### Goal
+
+```prolog
+% specifies that <variable> shall obtain <value> in the end
+goal(<variable>, <value>).
+```
+
+The goal specifies all variable assignments that have to be fulfilled after executing the plan.
+
+### Mutex Groups
+
+```prolog
+% declares a <mutex group>
+mutexGroup(mutexGroup(<number>)).
+
+% adds the assignment of <variable> to <value> to a <mutex group>
+contains(<mutex group>, <variable>, <value>).
+```
+
+SAS contains information about mutually exclusive [variable](#variables) assignments.
+That is, *at most one* variable assignment of each mutex group must be satisfied at all times.
+
+Mutex group facts are only present with SAS input programs and not PDDL.
+
+Mutex groups contain essential information in order to find plans correctly.
+That is, if mutex groups are present in `plasp`’s output, they have to be accounted for appropriately.
+
+### Axiom Rules
+
+```prolog
+% declares an <axiom rule>
+axiomRule(axiomRule(<number>)).
+
+% defines that as a precondition to <axiom rule>, <variable> must have value <value>
+precondition(<axiom rule>, <variable>, <value>).
+
+% defines that after applying <axiom rule>, <variable> is assigned <value>
+postcondition(<axiom rule>, effect(unconditional), <variable>, <value>).
+```
+
+Axiom rules are similar to [actions](#actions) in that they modify [variables](#variables) if certain preconditions are satisfied.
+However, axiom rules must be applied *immediately* as soon as their preconditions are satisfied.
+
+The second argument of `postcondition`, `effect(unconditional)`, is not used and exists only for consistency with [actions](#actions).
+
+Axiom rule facts are only present with SAS input programs and not PDDL.
+
+Axiom rules contain essential information in order to find plans correctly.
+That is, if axiom rules are present in `plasp`’s output, they have to be accounted for appropriately.

encodings/pddl-meta-sequential-incremental.lp

@@ -1,31 +0,0 @@
-#include <incmode>.
-
-#program base.
-
-% Establish initial state
-holds(Predicate, 0) :- initialState(Predicate).
-
-#program step(t).
-
-% Perform actions
-1 {occurs(action(Action), t) : action(Action)} 1.
-
-% Check preconditions
-:- occurs(Action, t), precondition(Action, Predicate, true), not holds(Predicate, t - 1).
-:- occurs(Action, t), precondition(Action, Predicate, false), holds(Predicate, t - 1).
-
-% Apply effects
-caused(Predicate, true, t) :- occurs(Action, t), postcondition(Action, Predicate, true).
-caused(Predicate, false, t) :- occurs(Action, t), postcondition(Action, Predicate, false).
-
-holds(Predicate, t) :- caused(Predicate, true, t).
-holds(Predicate, t) :- holds(Predicate, t - 1), not caused(Predicate, false, t).
-
-#program check(t).
-
-% Verify that goal is met
-:- query(t), goal(Predicate, true), not holds(Predicate, t).
-:- query(t), goal(Predicate, false), holds(Predicate, t).
-
-#show query/1.
-#show occurs/2.

encodings/sas-meta-sequential-incremental.lp

@@ -1,40 +0,0 @@
-#include <incmode>.
-
-% Check feature requirements
-:- requiresFeature(actionCosts).
-:- requiresFeature(axiomRules).
-:- requiresFeature(conditionalEffects).
-
-#program base.
-
-% Establish initial state
-holds(Var, Val, 0) :- initialState(Var, Val).
-
-#program step(t).
-
-% Perform actions
-1 {occurs(action(A), t) : action(A)} 1.
-
-% Check preconditions
-:- occurs(A, t), precondition(A, Var, Val), not holds(Var, Val, t - 1).
-
-% Apply effects
-caused(Var, Val, t) :- occurs(A, t), postcondition(A, _, Var, Val).
-modified(Var, t) :- caused(Var, Val, t).
-
-holds(Var, Val, t) :- caused(Var, Val, t).
-holds(Var, Val, t) :- holds(Var, Val, t - 1), not modified(Var, t).
-
-% Check that variables have unique values
-:- variable(X), Var = variable(X), not 1 {holds(Var, Val, t) : contains(Var, Val)} 1.
-
-% Check mutexes
-:- mutexGroup(X), M = mutexGroup(X), not {holds(Var, Val, t) : contains(M, Var, Val)} 1.
-
-#program check(t).
-
-% Verify that goal is met
-:- query(t), goal(Var, Val), not holds(Var, Val, t).
-
-#show query/1.
-#show occurs/2.

encodings/sequential-incremental.lp

@@ -0,0 +1,40 @@
+#include <incmode>.
+
+% Check feature requirements
+:- requires(feature(actionCosts)).
+:- requires(feature(axiomRules)).
+:- requires(feature(conditionalEffects)).
+
+#program base.
+
+% Establish initial state
+holds(Variable, Value, 0) :- initialState(Variable, Value).
+
+#program step(t).
+
+% Perform actions
+1 {occurs(Action, t) : action(Action)} 1.
+
+% Check preconditions
+:- occurs(Action, t), precondition(Action, Variable, Value), not holds(Variable, Value, t - 1).
+
+% Apply effects
+caused(Variable, Value, t) :- occurs(Action, t), postcondition(Action, _, Variable, Value).
+modified(Variable, t) :- caused(Variable, Value, t).
+
+holds(Variable, Value, t) :- caused(Variable, Value, t).
+holds(Variable, Value, t) :- holds(Variable, Value, t - 1), not modified(Variable, t).
+
+% Check that variables have unique values
+:- variable(Variable), not 1 {holds(Variable, Value, t) : contains(Variable, Value)} 1.
+
+% Check mutexes
+:- mutexGroup(MutexGroup), not {holds(Variable, Value, t) : contains(MutexGroup, Variable, Value)} 1.
+
+#program check(t).
+
+% Verify that goal is met
+:- query(t), goal(Variable, Value), not holds(Variable, Value, t).
+
+#show query/1.
+#show occurs/2.

include/plasp/LanguageDetection.h

@@ -13,15 +13,14 @@ namespace plasp
 //
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Language::Type detectLanguage(utils::Parser &parser)
+Language::Type detectLanguage(utils::Parser<utils::CaseInsensitiveParserPolicy> &parser)
 {
-	parser.setCaseSensitive(false);
 	parser.skipWhiteSpace();
 
 	// SAS begins with "begin_version"
-	if (parser.probe<std::string>("begin"))
+	if (parser.testAndSkip<std::string>("begin"))
 	{
-		parser.seek(std::ios::beg);
+		parser.seek(0);
 		return Language::Type::SAS;
 	}
 
@@ -33,7 +32,7 @@ Language::Type detectLanguage(utils::Parser &parser)
 	}
 
 	// PDDL contains sections starting with "(define"
-	if (parser.probe<std::string>("(") && parser.probe<std::string>("define"))
+	if (parser.testAndSkip<std::string>("(") && parser.testAndSkip<std::string>("define"))
 	{
 		parser.seek(std::ios::beg);
 		return Language::Type::PDDL;

include/plasp/pddl/Action.h

@@ -30,6 +30,8 @@ class Action
 		const Expression *precondition() const;
 		const Expression *effect() const;
 
+		void normalizeParameterNames();
+
 	private:
 		Action() = default;
 

include/plasp/pddl/Context.h

@@ -5,6 +5,7 @@
 #include <unordered_map>
 #include <vector>
 
+#include <plasp/pddl/Parser.h>
 #include <plasp/utils/Logger.h>
 
 namespace plasp
@@ -22,20 +23,21 @@ class Context
 {
 	public:
 		Context() = default;
+		~Context() = default;
 
-		explicit Context(utils::Parser &&parser)
-		:	parser{std::move(parser)}
+		explicit Context(Parser &&otherParser)
+		:	parser{std::move(otherParser)}
 		{
 		}
 
-		explicit Context(utils::Logger &&logger)
-		:	logger{std::move(logger)}
+		explicit Context(utils::Logger &&otherLogger)
+		:	logger{std::move(otherLogger)}
 		{
 		}
 
-		explicit Context(utils::Parser &&parser, utils::Logger &&logger)
-		:	parser{std::move(parser)},
-			logger{std::move(logger)}
+		explicit Context(Parser &&otherParser, utils::Logger &&otherLogger)
+		:	parser{std::move(otherParser)},
+			logger{std::move(otherLogger)}
 		{
 		}
 
@@ -56,7 +58,7 @@ class Context
 			return *this;
 		}
 
-		utils::Parser parser;
+		Parser parser;
 		utils::Logger logger;
 };
 

include/plasp/pddl/Description.h

@@ -35,6 +35,8 @@ class Description
 		bool containsProblem() const;
 		const Problem &problem() const;
 
+		void normalizeParameterNames();
+
 	private:
 		Description();
 
@@ -45,9 +47,9 @@ class Description
 
 		Context m_context;
 
-		utils::Parser::Position m_domainPosition;
+		utils::Stream::Position m_domainPosition;
 		std::unique_ptr<Domain> m_domain;
-		utils::Parser::Position m_problemPosition;
+		utils::Stream::Position m_problemPosition;
 		std::unique_ptr<Problem> m_problem;
 };
 

include/plasp/pddl/Domain.h

@@ -4,10 +4,11 @@
 #include <plasp/pddl/Action.h>
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Expression.h>
+#include <plasp/pddl/Parser.h>
+#include <plasp/pddl/Requirement.h>
 #include <plasp/pddl/expressions/Constant.h>
 #include <plasp/pddl/expressions/PredicateDeclaration.h>
 #include <plasp/pddl/expressions/PrimitiveType.h>
-#include <plasp/pddl/Requirement.h>
 
 namespace plasp
 {
@@ -34,7 +35,7 @@ class Domain
 
 		const Requirements &requirements() const;
 		bool hasRequirement(Requirement::Type requirementType) const;
-		void checkRequirement(Requirement::Type requirementType) const;
+		void checkRequirement(Requirement::Type requirementType);
 
 		expressions::PrimitiveTypes &types();
 		const expressions::PrimitiveTypes &types() const;
@@ -50,6 +51,8 @@ class Domain
 
 		void checkConsistency();
 
+		void normalizeParameterNames();
+
 	private:
 		void parseSection();
 
@@ -68,19 +71,19 @@ class Domain
 
 		std::string m_name;
 
-		utils::Parser::Position m_requirementsPosition;
+		utils::Stream::Position m_requirementsPosition;
 		Requirements m_requirements;
 
-		utils::Parser::Position m_typesPosition;
+		utils::Stream::Position m_typesPosition;
 		expressions::PrimitiveTypes m_types;
 
-		utils::Parser::Position m_constantsPosition;
+		utils::Stream::Position m_constantsPosition;
 		expressions::Constants m_constants;
 
-		utils::Parser::Position m_predicatesPosition;
+		utils::Stream::Position m_predicatesPosition;
 		expressions::PredicateDeclarations m_predicates;
 
-		std::vector<utils::Parser::Position> m_actionPositions;
+		std::vector<utils::Stream::Position> m_actionPositions;
 		std::vector<std::unique_ptr<Action>> m_actions;
 };
 

include/plasp/pddl/IO.h

@@ -3,7 +3,7 @@
 
 #include <iostream>
 
-#include <plasp/utils/Parser.h>
+#include <plasp/pddl/Parser.h>
 
 namespace plasp
 {
@@ -16,7 +16,7 @@ namespace pddl
 //
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-inline void skipSection(utils::Parser &parser)
+inline void skipSection(Parser &parser)
 {
 	size_t openParentheses = 1;
 

include/plasp/pddl/Parser.h

@@ -0,0 +1,49 @@
+#ifndef __PLASP__PDDL__PARSER_H
+#define __PLASP__PDDL__PARSER_H
+
+#include <plasp/utils/Parser.h>
+
+namespace plasp
+{
+namespace pddl
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// Parser
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+class PDDLParserPolicy
+{
+	public:
+		static char transformCharacter(char c) noexcept
+		{
+			return std::tolower(c);
+		}
+
+		static bool isWhiteSpaceCharacter(char c)
+		{
+			return std::iswspace(c);
+		}
+
+		static bool isIdentifierCharacter(char c)
+		{
+			return c != '?'
+				&& c != '('
+				&& c != ')'
+				&& c != ';'
+				&& std::isgraph(c);
+		}
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+using Parser = utils::Parser<PDDLParserPolicy>;
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}
+}
+
+#endif

include/plasp/pddl/Problem.h

@@ -4,6 +4,7 @@
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Expression.h>
 #include <plasp/pddl/InitialState.h>
+#include <plasp/pddl/Parser.h>
 #include <plasp/pddl/Requirement.h>
 
 namespace plasp
@@ -32,7 +33,7 @@ class Problem
 
 		const Requirements &requirements() const;
 		bool hasRequirement(Requirement::Type requirementType) const;
-		void checkRequirement(Requirement::Type requirementType) const;
+		void checkRequirement(Requirement::Type requirementType);
 
 		expressions::Constants &objects();
 		const expressions::Constants &objects() const;
@@ -61,18 +62,18 @@ class Problem
 
 		std::string m_name;
 
-		utils::Parser::Position m_domainPosition;
+		utils::Stream::Position m_domainPosition;
 
-		utils::Parser::Position m_requirementsPosition;
+		utils::Stream::Position m_requirementsPosition;
 		Requirements m_requirements;
 
-		utils::Parser::Position m_objectsPosition;
+		utils::Stream::Position m_objectsPosition;
 		expressions::Constants m_objects;
 
-		utils::Parser::Position m_initialStatePosition;
+		utils::Stream::Position m_initialStatePosition;
 		std::unique_ptr<InitialState> m_initialState;
 
-		utils::Parser::Position m_goalPosition;
+		utils::Stream::Position m_goalPosition;
 		ExpressionPointer m_goal;
 };
 

include/plasp/pddl/TranslatorASP.h

@@ -19,7 +19,7 @@ namespace pddl
 class TranslatorASP
 {
 	public:
-		explicit TranslatorASP(const Description &description, utils::LogStream &outputStream);
+		explicit TranslatorASP(Description &description, utils::LogStream &outputStream);
 
 		void translate() const;
 
@@ -39,7 +39,7 @@ class TranslatorASP
 		void translateLiteral(const Expression &literal) const;
 		void translatePredicate(const expressions::Predicate &predicate) const;
 
-		const Description &m_description;
+		Description &m_description;
 		utils::LogStream &m_outputStream;
 };
 

include/plasp/pddl/expressions/At.h

@@ -3,7 +3,6 @@
 
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Expression.h>
-#include <plasp/pddl/Identifier.h>
 
 namespace plasp
 {
@@ -57,8 +56,8 @@ AtPointer At::parse(Context &context, ExpressionContext &expressionContext,
 
 	const auto position = parser.position();
 
-	if (!parser.probe<std::string>("(")
-		|| !parser.probeIdentifier("at", isIdentifier))
+	if (!parser.testAndSkip<std::string>("(")
+		|| !parser.testIdentifierAndSkip("at"))
 	{
 		parser.seek(position);
 		return nullptr;
@@ -68,9 +67,9 @@ AtPointer At::parse(Context &context, ExpressionContext &expressionContext,
 
 	const auto timePointPosition = parser.position();
 
-	if (parser.probeIdentifier("start", isIdentifier))
+	if (parser.testIdentifierAndSkip("start"))
 		timePoint = TimePointStart;
-	else if (parser.probeIdentifier("end", isIdentifier))
+	else if (parser.testIdentifierAndSkip("end"))
 		timePoint = TimePointEnd;
 	else if (parser.probeNumber())
 	{

include/plasp/pddl/expressions/Binary.h

@@ -4,7 +4,6 @@
 #include <plasp/pddl/ConsistencyException.h>
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Expression.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/expressions/Variable.h>
 
 namespace plasp
@@ -52,8 +51,8 @@ std::unique_ptr<Derived> Binary<Derived>::parse(Context &context,
 
 	const auto position = parser.position();
 
-	if (!parser.probe<std::string>("(")
-		|| !parser.probeIdentifier(Derived::Identifier, isIdentifier))
+	if (!parser.testAndSkip<std::string>("(")
+		|| !parser.testIdentifierAndSkip(Derived::Identifier))
 	{
 		parser.seek(position);
 		return nullptr;

include/plasp/pddl/expressions/Constant.h

@@ -2,7 +2,6 @@
 #define __PLASP__PDDL__EXPRESSIONS__CONSTANT_H
 
 #include <plasp/pddl/Expression.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/utils/Parser.h>
 #include <plasp/utils/ParserException.h>
 

include/plasp/pddl/expressions/NAry.h

@@ -4,7 +4,6 @@
 #include <plasp/pddl/ConsistencyException.h>
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Expression.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/expressions/Variable.h>
 
 namespace plasp
@@ -50,8 +49,8 @@ std::unique_ptr<Derived> NAry<Derived>::parse(Context &context,
 
 	const auto position = parser.position();
 
-	if (!parser.probe<std::string>("(")
-		|| !parser.probeIdentifier(Derived::Identifier, isIdentifier))
+	if (!parser.testAndSkip<std::string>("(")
+		|| !parser.testIdentifierAndSkip(Derived::Identifier))
 	{
 		parser.seek(position);
 		return nullptr;
@@ -71,7 +70,7 @@ std::unique_ptr<Derived> NAry<Derived>::parse(Context &context,
 	}
 
 	if (expression->m_arguments.empty())
-		context.logger.logWarning(context.parser, "“" + Derived::Identifier + "” expressions should not be empty");
+		context.logger.logWarning(parser.coordinate(), "“" + Derived::Identifier + "” expressions should not be empty");
 
 	parser.expect<std::string>(")");
 

include/plasp/pddl/expressions/Not.h

@@ -3,7 +3,6 @@
 
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Expression.h>
-#include <plasp/pddl/Identifier.h>
 
 namespace plasp
 {
@@ -50,8 +49,8 @@ NotPointer Not::parse(Context &context, ExpressionContext &expressionContext,
 
 	const auto position = parser.position();
 
-	if (!parser.probe<std::string>("(")
-		|| !parser.probeIdentifier("not", isIdentifier))
+	if (!parser.testAndSkip<std::string>("(")
+		|| !parser.testIdentifierAndSkip("not"))
 	{
 		parser.seek(position);
 		return nullptr;

include/plasp/pddl/expressions/PredicateDeclaration.h

@@ -29,6 +29,8 @@ class PredicateDeclaration: public ExpressionCRTP<PredicateDeclaration>
 
 		bool isDeclared() const;
 
+		void normalizeParameterNames();
+
 	private:
 		PredicateDeclaration();
 

include/plasp/pddl/expressions/PrimitiveType.h

@@ -3,7 +3,6 @@
 
 #include <plasp/pddl/ConsistencyException.h>
 #include <plasp/pddl/Expression.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/utils/ParserException.h>
 
 namespace plasp

include/plasp/pddl/expressions/Variable.h

@@ -28,7 +28,9 @@ class Variable: public ExpressionCRTP<Variable>
 			const ExpressionContext &expressionContext);
 
 	public:
+		void setName(std::string name);
 		const std::string &name() const;
+
 		const Expression *type() const;
 
 		void setDirty(bool isDirty = true);

include/plasp/sas/AssignedVariable.h

@@ -27,8 +27,8 @@ using AssignedVariables = std::vector<AssignedVariable>;
 class AssignedVariable
 {
 	public:
-		static AssignedVariable fromSAS(utils::Parser &parser, const Variables &variables);
-		static AssignedVariable fromSAS(utils::Parser &parser, const Variable &variable);
+		static AssignedVariable fromSAS(utils::Parser<> &parser, const Variables &variables);
+		static AssignedVariable fromSAS(utils::Parser<> &parser, const Variable &variable);
 
 	public:
 		explicit AssignedVariable(const Variable &variable, const Value &value);

include/plasp/sas/AxiomRule.h

@@ -29,7 +29,7 @@ class AxiomRule
 		using Condition = AssignedVariable;
 		using Conditions = AssignedVariables;
 
-		static AxiomRule fromSAS(utils::Parser &parser, const Variables &variables);
+		static AxiomRule fromSAS(utils::Parser<> &parser, const Variables &variables);
 
 	public:
 		const Conditions &conditions() const;

include/plasp/sas/Description.h

@@ -29,7 +29,7 @@ namespace sas
 class Description
 {
 	public:
-		static Description fromParser(utils::Parser &&parser);
+		static Description fromParser(utils::Parser<> &&parser);
 		static Description fromStream(std::istream &istream);
 		static Description fromFile(const boost::filesystem::path &path);
 
@@ -45,19 +45,21 @@ class Description
 		bool usesAxiomRules() const;
 		bool usesConditionalEffects() const;
 
+		bool hasRequirements() const;
+
 	private:
 		Description();
 
-		void parseContent(utils::Parser &parser);
+		void parseContent(utils::Parser<> &parser);
 
-		void parseVersionSection(utils::Parser &parser) const;
-		void parseMetricSection(utils::Parser &parser);
-		void parseVariablesSection(utils::Parser &parser);
-		void parseMutexSection(utils::Parser &parser);
-		void parseInitialStateSection(utils::Parser &parser);
-		void parseGoalSection(utils::Parser &parser);
-		void parseOperatorSection(utils::Parser &parser);
-		void parseAxiomSection(utils::Parser &parser);
+		void parseVersionSection(utils::Parser<> &parser) const;
+		void parseMetricSection(utils::Parser<> &parser);
+		void parseVariablesSection(utils::Parser<> &parser);
+		void parseMutexSection(utils::Parser<> &parser);
+		void parseInitialStateSection(utils::Parser<> &parser);
+		void parseGoalSection(utils::Parser<> &parser);
+		void parseOperatorSection(utils::Parser<> &parser);
+		void parseAxiomSection(utils::Parser<> &parser);
 
 		bool m_usesActionCosts;
 

include/plasp/sas/Effect.h

@@ -29,7 +29,7 @@ class Effect
 		using Condition = AssignedVariable;
 		using Conditions = AssignedVariables;
 
-		static Effect fromSAS(utils::Parser &parser, const Variables &variables, Conditions &preconditions);
+		static Effect fromSAS(utils::Parser<> &parser, const Variables &variables, Conditions &preconditions);
 
 	public:
 		const Conditions &conditions() const;

include/plasp/sas/Goal.h

@@ -21,7 +21,7 @@ class Goal
 		using Fact = AssignedVariable;
 		using Facts = AssignedVariables;
 
-		static Goal fromSAS(utils::Parser &parser, const Variables &variables);
+		static Goal fromSAS(utils::Parser<> &parser, const Variables &variables);
 
 	public:
 		const Facts &facts() const;

include/plasp/sas/InitialState.h

@@ -21,7 +21,7 @@ class InitialState
 		using Fact = AssignedVariable;
 		using Facts = AssignedVariables;
 
-		static InitialState fromSAS(utils::Parser &parser, const Variables &variables);
+		static InitialState fromSAS(utils::Parser<> &parser, const Variables &variables);
 
 	public:
 		const Facts &facts() const;

include/plasp/sas/MutexGroup.h

@@ -28,7 +28,7 @@ class MutexGroup
 		using Fact = AssignedVariable;
 		using Facts = AssignedVariables;
 
-		static MutexGroup fromSAS(utils::Parser &parser, const Variables &variables);
+		static MutexGroup fromSAS(utils::Parser<> &parser, const Variables &variables);
 
 	public:
 		const Facts &facts() const;

include/plasp/sas/Operator.h

@@ -33,7 +33,7 @@ class Operator
 		using Condition = AssignedVariable;
 		using Conditions = AssignedVariables;
 
-		static Operator fromSAS(utils::Parser &parser, const Variables &variables);
+		static Operator fromSAS(utils::Parser<> &parser, const Variables &variables);
 
 	public:
 		void printPredicateAsASP(utils::LogStream &ostream) const;

include/plasp/sas/Predicate.h

@@ -22,7 +22,7 @@ namespace sas
 class Predicate
 {
 	public:
-		static Predicate fromSAS(utils::Parser &parser);
+		static Predicate fromSAS(utils::Parser<> &parser);
 
 		using Arguments = std::vector<std::string>;
 

include/plasp/sas/Value.h

@@ -39,14 +39,13 @@ struct Value
 		static const Value Any;
 		static const Value None;
 
-		static Value fromSAS(utils::Parser &parser);
-		static const Value &referenceFromSAS(utils::Parser &parser, const Variable &variable);
+		static Value fromSAS(utils::Parser<> &parser);
+		static const Value &referenceFromSAS(utils::Parser<> &parser, const Variable &variable);
 
 	public:
 		Value negated() const;
 
 		void printAsSAS(utils::LogStream &outputStream) const;
-		void printAsASP(utils::LogStream &outputStream) const;
 		void printAsASPPredicate(utils::LogStream &outputStream) const;
 
 		Sign sign() const;

include/plasp/sas/Variable.h

@@ -28,8 +28,8 @@ using Variables = std::vector<Variable>;
 class Variable
 {
 	public:
-		static Variable fromSAS(utils::Parser &parser);
-		static const Variable &referenceFromSAS(utils::Parser &parser, const Variables &variables);
+		static Variable fromSAS(utils::Parser<> &parser);
+		static const Variable &referenceFromSAS(utils::Parser<> &parser, const Variables &variables);
 
 	public:
 		void printNameAsASPPredicate(utils::LogStream &outputStream) const;

include/plasp/sas/VariableTransition.h

@@ -26,7 +26,7 @@ using VariableTransitions = std::vector<VariableTransition>;
 class VariableTransition
 {
 	public:
-		static VariableTransition fromSAS(utils::Parser &parser, const Variables &variables);
+		static VariableTransition fromSAS(utils::Parser<> &parser, const Variables &variables);
 
 	public:
 		const Variable &variable() const;

include/plasp/utils/Formatting.h

@@ -93,6 +93,26 @@ struct Token
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+struct RuleName: public Token
+{
+	RuleName(const std::string &name)
+	:	Token(name)
+	{
+	}
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+inline LogStream &operator<<(LogStream &stream, const RuleName &keyword)
+{
+	return (stream
+		<< utils::Format(utils::Color::White, utils::FontWeight::Bold)
+		<< keyword.name
+		<< utils::ResetFormat());
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 struct Keyword: public Token
 {
 	Keyword(const std::string &name)
@@ -106,11 +126,10 @@ struct Keyword: public Token
 inline LogStream &operator<<(LogStream &stream, const Keyword &keyword)
 {
 	return (stream
-		<< utils::Format(utils::Color::White, utils::FontWeight::Bold)
+		<< utils::Format(utils::Color::Blue, utils::FontWeight::Normal)
 		<< keyword.name
 		<< utils::ResetFormat());
 }
-
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 struct Number: public Token
@@ -126,7 +145,7 @@ struct Number: public Token
 inline LogStream &operator<<(LogStream &stream, const Number &number)
 {
 	return (stream
-		<< utils::Format(utils::Color::Yellow, utils::FontWeight::Bold)
+		<< utils::Format(utils::Color::Yellow, utils::FontWeight::Normal)
 		<< number.name
 		<< utils::ResetFormat());
 }
@@ -153,6 +172,66 @@ inline LogStream &operator<<(LogStream &stream, const Variable &variable)
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+struct String: public Token
+{
+	String(const std::string &name)
+	:	Token(name)
+	{
+	}
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+inline LogStream &operator<<(LogStream &stream, const String &string)
+{
+	return (stream
+		<< utils::Format(utils::Color::Green, utils::FontWeight::Normal)
+		<< "\"" << string.name << "\""
+		<< utils::ResetFormat());
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+struct Boolean: public Token
+{
+	Boolean(const std::string &name)
+	:	Token(name)
+	{
+	}
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+inline LogStream &operator<<(LogStream &stream, const Boolean &string)
+{
+	return (stream
+		<< utils::Format(utils::Color::Red, utils::FontWeight::Normal)
+		<< string.name
+		<< utils::ResetFormat());
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+struct Reserved: public Token
+{
+	Reserved(const std::string &name)
+	:	Token(name)
+	{
+	}
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+inline LogStream &operator<<(LogStream &stream, const Reserved &string)
+{
+	return (stream
+		<< utils::Format(utils::Color::White, utils::FontWeight::Normal)
+		<< string.name
+		<< utils::ResetFormat());
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 struct Heading1: public Token
 {
 	Heading1(const std::string &name)

include/plasp/utils/IO.h

@@ -1,57 +0,0 @@
-#ifndef __PLASP__UTILS__IO_H
-#define __PLASP__UTILS__IO_H
-
-#include <boost/algorithm/string/replace.hpp>
-
-namespace plasp
-{
-namespace utils
-{
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-//
-// IO
-//
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
-inline std::string escapeASP(const std::string &string)
-{
-	auto escaped = string;
-
-	boost::replace_all(escaped, "_", "__");
-	boost::replace_all(escaped, "-", "_h");
-	boost::replace_all(escaped, "@", "_a");
-
-	return escaped;
-}
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
-inline std::string unescapeASP(const std::string &string)
-{
-	auto unescaped = string;
-
-	boost::replace_all(unescaped, "_a", "@");
-	boost::replace_all(unescaped, "_h", "-");
-	boost::replace_all(unescaped, "__", "_");
-
-	return unescaped;
-}
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
-inline std::string escapeASPVariable(const std::string &string)
-{
-	auto escaped = escapeASP(string);
-
-	escaped.front() = std::toupper(escaped.front());
-
-	return escaped;
-}
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
-}
-}
-
-#endif

include/plasp/utils/LogStream.h

@@ -118,11 +118,17 @@ class LogStream
 		inline LogStream &operator<<(bool value);
 		inline LogStream &operator<<(const void *value);
 		inline LogStream &operator<<(const char *value);
+		inline LogStream &operator<<(const signed char *value);
+		inline LogStream &operator<<(const unsigned char *value);
 		inline LogStream &operator<<(std::basic_streambuf<CharacterType, TraitsType> *sb);
 		inline LogStream &operator<<(std::ios_base &(*func)(std::ios_base &));
 		inline LogStream &operator<<(std::basic_ios<CharacterType, TraitsType> &(*func)(std::basic_ios<CharacterType, TraitsType> &));
 		inline LogStream &operator<<(std::basic_ostream<CharacterType, TraitsType> &(*func)(std::basic_ostream<CharacterType, TraitsType> &));
 
+		inline LogStream &operator<<(char value);
+		inline LogStream &operator<<(signed char value);
+		inline LogStream &operator<<(unsigned char value);
+
 	private:
 		StandardStream m_standardStream;
 		ColorPolicy m_colorPolicy;
@@ -242,6 +248,22 @@ LogStream &LogStream::operator<<(const char *value)
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+LogStream &LogStream::operator<<(const signed char *value)
+{
+	ostream() << value;
+	return *this;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+LogStream &LogStream::operator<<(const unsigned char *value)
+{
+	ostream() << value;
+	return *this;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 LogStream &LogStream::operator<<(std::basic_streambuf<CharacterType, TraitsType>* sb)
 {
 	ostream() << sb;
@@ -283,6 +305,30 @@ inline LogStream &operator<<(LogStream &stream, const std::basic_string<Characte
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+LogStream &LogStream::operator<<(char value)
+{
+	ostream() << value;
+	return *this;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+LogStream &LogStream::operator<<(signed char value)
+{
+	ostream() << value;
+	return *this;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+LogStream &LogStream::operator<<(unsigned char value)
+{
+	ostream() << value;
+	return *this;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 }
 }
 

include/plasp/utils/Logger.h

@@ -4,8 +4,8 @@
 #include <string>
 
 #include <plasp/utils/LogStream.h>
-#include <plasp/utils/Parser.h>
 #include <plasp/utils/ParserException.h>
+#include <plasp/utils/StreamCoordinate.h>
 
 namespace plasp
 {
@@ -44,8 +44,8 @@ class Logger
 		void setColorPolicy(LogStream::ColorPolicy colorPolicy);
 
 		void logError(const std::string &message);
-		void logError(const Parser::Coordinate &coordinate, const std::string &message);
-		void logWarning(const Parser &parser, const std::string &message);
+		void logError(const StreamCoordinate &coordinate, const std::string &message);
+		void logWarning(const StreamCoordinate &parserCoordinate, const std::string &message);
 
 	private:
 		LogStream m_outputStream;

include/plasp/utils/Parser.h

@@ -8,111 +8,194 @@
 
 #include <boost/filesystem.hpp>
 
+#include <plasp/utils/ParserException.h>
+#include <plasp/utils/ParserPolicy.h>
+#include <plasp/utils/Stream.h>
+#include <plasp/utils/StreamCoordinate.h>
+
 namespace plasp
 {
 namespace utils
 {
 
+template<typename Type>
+struct Tag
+{
+};
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 //
 // Parser
 //
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-class Parser
+template<class ParserPolicy = CaseSensitiveParserPolicy>
+class Parser: public Stream, public ParserPolicy
 {
-	public:
-		using Position = std::stringstream::pos_type;
-
-		struct Coordinate
-		{
-			std::string sectionName;
-			size_t row;
-			size_t column;
-		};
-
-		struct StreamDelimiter
-		{
-			Position position;
-			std::string sectionName;
-		};
+	template<class OtherParserPolicy>
+	friend class Parser;
 
 	public:
 		explicit Parser();
 		explicit Parser(std::string streamName, std::istream &istream);
 
-		// Forbid copy construction/assignment
-		Parser(const Parser &other) = delete;
-		Parser &operator=(const Parser &other) = delete;
-
-		Parser(Parser &&other);
-		Parser &operator=(Parser &&other);
-
-		void readStream(std::string streamName, std::istream &istream);
-		void readFile(const boost::filesystem::path &path);
-
-		void reset();
-		void seek(Position position);
-		Position position() const;
-		Coordinate coordinate() const;
-
-		void setCaseSensitive(bool isCaseInsensitive = true);
-
-		char currentCharacter() const;
-		void advance();
-		bool atEndOfStream() const;
+		template<class OtherParser>
+		Parser(OtherParser &&otherParser)
+		{
+			m_stream = std::move(otherParser.m_stream);
+			m_delimiters = std::move(otherParser.m_delimiters);
+		}
 
 		void removeComments(const std::string &startSequence, const std::string &endSequence, bool removeEnd);
 
+		char currentCharacter() const;
+
 		template<typename Type>
 		Type parse();
 
-		template<class CharacterPredicate, class WhiteSpacePredicate>
-		std::string parseIdentifier(CharacterPredicate characterPredicate, WhiteSpacePredicate whiteSpacePredicate);
-
-		template<class CharacterPredicate>
-		std::string parseIdentifier(CharacterPredicate characterPredicate);
+		template<typename Type>
+		bool testAndReturn(const Type &expectedValue);
 
 		template<typename Type>
-		bool probe(const Type &expectedValue);
-
-		template<class CharacterPredicate>
-		bool probeIdentifier(const std::string &identifier, CharacterPredicate characterPredicate);
-
-		bool probeNumber();
+		bool testAndSkip(const Type &expectedValue);
 
 		template<typename Type>
 		void expect(const Type &expectedValue);
 
-		template<class WhiteSpacePredicate>
-		void skipWhiteSpace(WhiteSpacePredicate whiteSpacePredicate);
+		std::string parseIdentifier();
+		bool testIdentifierAndReturn(const std::string &identifier);
+		bool testIdentifierAndSkip(const std::string &identifier);
+
+		// TODO: remove
+		bool probeNumber();
+
+		std::string parseLine();
 
 		void skipWhiteSpace();
 		void skipLine();
 
-		std::string getLine();
-
 	private:
-		static const std::istreambuf_iterator<char> EndOfFile;
+		std::string parseImpl(Tag<std::string>);
+		char parseImpl(Tag<char>);
+		uint64_t parseImpl(Tag<uint64_t>);
+		int64_t parseImpl(Tag<int64_t>);
+		uint32_t parseImpl(Tag<uint32_t>);
+		int32_t parseImpl(Tag<int32_t>);
+		bool parseImpl(Tag<bool>);
 
-	private:
-		void checkStream() const;
+		bool testImpl(const std::string &expectedValue);
+		bool testImpl(char expectedValue);
+		bool testImpl(uint64_t expectedValue);
+		bool testImpl(int64_t expectedValue);
+		bool testImpl(uint32_t expectedValue);
+		bool testImpl(int32_t expectedValue);
+		bool testImpl(bool expectedValue);
 
 		uint64_t parseIntegerBody();
-
-		mutable std::stringstream m_stream;
-
-		std::vector<StreamDelimiter> m_streamDelimiters;
-
-		bool m_isCaseSensitive;
 };
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-template<class CharacterPredicate, class WhiteSpacePredicate>
-std::string Parser::parseIdentifier(CharacterPredicate characterPredicate, WhiteSpacePredicate whiteSpacePredicate)
+template<class ParserPolicy>
+Parser<ParserPolicy>::Parser()
+:	Stream()
 {
-	skipWhiteSpace(whiteSpacePredicate);
+}
+
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+Parser<ParserPolicy>::Parser(std::string streamName, std::istream &istream)
+:	Stream(streamName, istream)
+{
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+void Parser<ParserPolicy>::skipWhiteSpace()
+{
+	check();
+
+	while (!atEnd() && ParserPolicy::isWhiteSpaceCharacter(currentCharacter()))
+		advance();
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+void Parser<ParserPolicy>::skipLine()
+{
+	check();
+
+	while (currentCharacter() != '\n')
+		advance();
+
+	advance();
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+template<typename Type>
+Type Parser<ParserPolicy>::parse()
+{
+	return parseImpl(Tag<Type>());
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+template<typename Type>
+bool Parser<ParserPolicy>::testAndReturn(const Type &expectedValue)
+{
+	const auto previousPosition = position();
+
+	const auto result = testImpl(expectedValue);
+
+	seek(previousPosition);
+
+	return result;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+template<typename Type>
+bool Parser<ParserPolicy>::testAndSkip(const Type &expectedValue)
+{
+	const auto previousPosition = position();
+
+	const auto result = testImpl(expectedValue);
+
+	if (result == false)
+		seek(previousPosition);
+
+	return result;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+template<typename Type>
+void Parser<ParserPolicy>::expect(const Type &expectedValue)
+{
+	if (testAndSkip(expectedValue))
+		return;
+
+	std::stringstream message;
+	message << "unexpected value, expected “" << expectedValue << "”";
+
+	throw ParserException(coordinate(), message.str());
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+std::string Parser<ParserPolicy>::parseIdentifier()
+{
+	skipWhiteSpace();
 
 	std::string value;
 
@@ -120,7 +203,7 @@ std::string Parser::parseIdentifier(CharacterPredicate characterPredicate, White
 	{
 		const auto character = currentCharacter();
 
-		if (!characterPredicate(character))
+		if (!ParserPolicy::isIdentifierCharacter(character))
 			return value;
 
 		value.push_back(character);
@@ -130,33 +213,342 @@ std::string Parser::parseIdentifier(CharacterPredicate characterPredicate, White
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-template<class CharacterPredicate>
-std::string Parser::parseIdentifier(CharacterPredicate characterPredicate)
+template<class ParserPolicy>
+bool Parser<ParserPolicy>::testIdentifierAndSkip(const std::string &expectedValue)
 {
-	return parseIdentifier(characterPredicate,
-		[&](const auto character)
-		{
-			return std::isspace(character);
-		});
+	return testAndSkip(expectedValue) && !ParserPolicy::isIdentifierCharacter(currentCharacter());
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-template<class CharacterPredicate>
-bool Parser::probeIdentifier(const std::string &expectedValue, CharacterPredicate characterPredicate)
+template<class ParserPolicy>
+bool Parser<ParserPolicy>::probeNumber()
 {
-	return probe<std::string>(expectedValue) && !characterPredicate(currentCharacter());
+	const auto previousPosition = position();
+
+	skipWhiteSpace();
+
+	while (!ParserPolicy::isWhiteSpaceCharacter(currentCharacter()))
+		if (!std::isdigit(currentCharacter()))
+		{
+			seek(previousPosition);
+
+			return false;
+		}
+
+	return true;
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-template<class WhiteSpacePredicate>
-void Parser::skipWhiteSpace(WhiteSpacePredicate whiteSpacePredicate)
+template<class ParserPolicy>
+std::string Parser<ParserPolicy>::parseLine()
 {
-	checkStream();
+	std::string value;
 
-	while (!atEndOfStream() && whiteSpacePredicate(currentCharacter()))
+	while (true)
+	{
+		const auto character = currentCharacter();
 		advance();
+
+		if (character == '\n')
+			break;
+		else if (character == '\r')
+			continue;
+
+		value.push_back(character);
+	}
+
+	return value;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+void Parser<ParserPolicy>::removeComments(const std::string &startSequence, const std::string &endSequence, bool removeEnd)
+{
+	const auto inPosition = m_stream.tellg();
+	const auto outPosition = m_stream.tellp();
+
+	m_stream.seekg(0);
+
+	const auto removeRange =
+		[&](const auto &start, const auto &end)
+		{
+			BOOST_ASSERT(start != -1);
+
+			m_stream.clear();
+			m_stream.seekp(start);
+			m_stream.seekg(start);
+
+			auto position = start;
+
+			while (end == -1 || position < end)
+			{
+				m_stream.ignore(1);
+
+				if (atEnd())
+					return;
+
+				m_stream.put(' ');
+				position += static_cast<std::streamoff>(1);
+			}
+		};
+
+	while (!atEnd())
+	{
+		Position startPosition = m_stream.tellg();
+
+		while (!atEnd())
+		{
+			startPosition = m_stream.tellg();
+
+			if (testAndSkip(startSequence))
+				break;
+
+			advance();
+		}
+
+		Position endPosition = m_stream.tellg();
+
+		while (!atEnd())
+		{
+			endPosition = m_stream.tellg();
+
+			if (testAndSkip(endSequence))
+				break;
+
+			advance();
+		}
+
+		if (removeEnd)
+			endPosition = m_stream.tellg();
+
+		removeRange(startPosition, endPosition);
+	}
+
+	m_stream.clear();
+
+	m_stream.seekg(inPosition);
+	m_stream.seekp(outPosition);
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+char Parser<ParserPolicy>::currentCharacter() const
+{
+	return ParserPolicy::transformCharacter(Stream::currentCharacter());
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+std::string Parser<ParserPolicy>::parseImpl(Tag<std::string>)
+{
+	skipWhiteSpace();
+
+	const auto startPosition = position();
+
+	while (!ParserPolicy::isWhiteSpaceCharacter(currentCharacter()))
+		advance();
+
+	const auto endPosition = position();
+	const auto length = static_cast<size_t>(endPosition - startPosition);
+
+	std::string value;
+	value.reserve(length);
+
+	seek(startPosition);
+
+	for (size_t i = 0; i < length; i++)
+	{
+		value.push_back(currentCharacter());
+		advance();
+	}
+
+	return value;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+char Parser<ParserPolicy>::parseImpl(Tag<char>)
+{
+	const auto value = currentCharacter();
+
+	advance();
+
+	return value;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+uint64_t Parser<ParserPolicy>::parseIntegerBody()
+{
+	check();
+
+	if (!std::isdigit(currentCharacter()))
+		throw ParserException(coordinate(), "could not parse integer value");
+
+	uint64_t value = 0;
+
+	while (!atEnd())
+	{
+		const auto character = currentCharacter();
+
+		if (!std::isdigit(character))
+			break;
+
+		value *= 10;
+		value += character - '0';
+
+		advance();
+	}
+
+	return value;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+int64_t Parser<ParserPolicy>::parseImpl(Tag<int64_t>)
+{
+	skipWhiteSpace();
+
+	bool positive = testAndSkip<char>('+') || !testAndSkip<char>('-');
+
+	const auto value = parseIntegerBody();
+
+	return (positive ? value : -value);
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+uint64_t Parser<ParserPolicy>::parseImpl(Tag<uint64_t>)
+{
+	skipWhiteSpace();
+
+	if (currentCharacter() == '-')
+		throw ParserException(coordinate(), "expected unsigned integer, got signed one");
+
+	return parseIntegerBody();
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+int32_t Parser<ParserPolicy>::parseImpl(Tag<int32_t>)
+{
+	return static_cast<int32_t>(parseImpl(Tag<int64_t>()));
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+uint32_t Parser<ParserPolicy>::parseImpl(Tag<uint32_t>)
+{
+	return static_cast<uint32_t>(parseImpl(Tag<uint64_t>()));
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+bool Parser<ParserPolicy>::parseImpl(Tag<bool>)
+{
+	skipWhiteSpace();
+
+	if (testAndSkip<char>('0'))
+	    return false;
+
+	if (testAndSkip<char>('1'))
+		return true;
+
+	throw ParserException(coordinate(), "could not parse Boolean value");
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+bool Parser<ParserPolicy>::testImpl(const std::string &expectedValue)
+{
+	if (!ParserPolicy::isWhiteSpaceCharacter(expectedValue.front()))
+		skipWhiteSpace();
+
+	const auto match = std::find_if(expectedValue.cbegin(), expectedValue.cend(),
+		[&](const auto &expectedCharacter)
+		{
+			const auto character = static_cast<char>(this->currentCharacter());
+
+			if (character != expectedCharacter)
+				return true;
+
+			this->advance();
+
+			return false;
+		});
+
+	return (match == expectedValue.cend());
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+bool Parser<ParserPolicy>::testImpl(char expectedValue)
+{
+	const auto result = (currentCharacter() == expectedValue);
+
+	advance();
+
+	return result;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+bool Parser<ParserPolicy>::testImpl(int64_t expectedValue)
+{
+	const auto value = parseImpl(Tag<int64_t>());
+
+	return (value == expectedValue);
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+bool Parser<ParserPolicy>::testImpl(uint64_t expectedValue)
+{
+	const auto value = parseImpl(Tag<uint64_t>());
+
+	return (value == expectedValue);
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+bool Parser<ParserPolicy>::testImpl(int32_t expectedValue)
+{
+	return testImpl(static_cast<int64_t>(expectedValue));
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+bool Parser<ParserPolicy>::testImpl(uint32_t expectedValue)
+{
+	return testImpl(static_cast<uint64_t>(expectedValue));
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<class ParserPolicy>
+bool Parser<ParserPolicy>::testImpl(bool expectedValue)
+{
+	const auto value = parseImpl(Tag<bool>());
+
+	return (value == expectedValue);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////

include/plasp/utils/ParserException.h

@@ -4,7 +4,7 @@
 #include <exception>
 #include <string>
 
-#include <plasp/utils/Parser.h>
+#include <plasp/utils/StreamCoordinate.h>
 
 namespace plasp
 {
@@ -20,18 +20,18 @@ namespace utils
 class ParserException: public std::exception
 {
 	public:
-		explicit ParserException(const utils::Parser &parser)
-		:	ParserException(parser, "unspecified parser error")
+		explicit ParserException(const StreamCoordinate &coordinate)
+		:	ParserException(coordinate, "unspecified parser error")
 		{
 		}
 
-		explicit ParserException(const utils::Parser &parser, const char *message)
-		:	ParserException(parser, static_cast<std::string>(message))
+		explicit ParserException(const StreamCoordinate &coordinate, const char *message)
+		:	ParserException(coordinate, static_cast<std::string>(message))
 		{
 		}
 
-		explicit ParserException(const utils::Parser &parser, const std::string &message)
-		:	m_coordinate{parser.coordinate()},
+		explicit ParserException(const StreamCoordinate &coordinate, const std::string &message)
+		:	m_coordinate{coordinate},
 			m_message{message},
 			m_plainMessage{m_coordinate.sectionName + ":" + std::to_string(m_coordinate.row)
 				+ ":" + std::to_string(m_coordinate.column) + " " + m_message}
@@ -47,7 +47,7 @@ class ParserException: public std::exception
 			return m_plainMessage.c_str();
 		}
 
-		const Parser::Coordinate &coordinate() const
+		const StreamCoordinate &coordinate() const
 		{
 			return m_coordinate;
 		}
@@ -58,7 +58,7 @@ class ParserException: public std::exception
 		}
 
 	private:
-		Parser::Coordinate m_coordinate;
+		StreamCoordinate m_coordinate;
 		std::string m_message;
 		std::string m_plainMessage;
 };

include/plasp/utils/ParserPolicy.h

@@ -0,0 +1,62 @@
+#ifndef __PLASP__UTILS__PARSER_POLICY_H
+#define __PLASP__UTILS__PARSER_POLICY_H
+
+#include <iostream>
+
+namespace plasp
+{
+namespace utils
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// ParserPolicy
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+class CaseSensitiveParserPolicy
+{
+	public:
+		static constexpr char transformCharacter(char c) noexcept
+		{
+			return c;
+		}
+
+		static bool isWhiteSpaceCharacter(char c)
+		{
+			return std::iswspace(c);
+		}
+
+		static bool isIdentifierCharacter(char c)
+		{
+			return std::isgraph(c);
+		}
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+class CaseInsensitiveParserPolicy
+{
+	public:
+		static char transformCharacter(char c) noexcept
+		{
+			return std::tolower(c);
+		}
+
+		static bool isWhiteSpaceCharacter(char c)
+		{
+			return std::iswspace(c);
+		}
+
+		static bool isIdentifierCharacter(char c)
+		{
+			return std::isgraph(c);
+		}
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}
+}
+
+#endif

include/plasp/utils/Stream.h

@@ -0,0 +1,84 @@
+#ifndef __PLASP__UTILS__STREAM_H
+#define __PLASP__UTILS__STREAM_H
+
+#include <iostream>
+#include <iterator>
+#include <sstream>
+#include <vector>
+
+#include <boost/filesystem.hpp>
+
+#include <plasp/utils/ParserException.h>
+#include <plasp/utils/StreamCoordinate.h>
+
+namespace plasp
+{
+namespace utils
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// Stream
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+class Stream
+{
+	public:
+		using Position = std::stringstream::pos_type;
+
+		struct Delimiter
+		{
+			Position position;
+			std::string sectionName;
+		};
+
+	public:
+		explicit Stream();
+		explicit Stream(std::string streamName, std::istream &istream);
+
+		Stream(const Stream &other) = delete;
+		Stream &operator=(const Stream &other) = delete;
+
+		Stream(Stream &&other)
+		:	m_stream{std::move(other.m_stream)},
+			m_delimiters{std::move(other.m_delimiters)}
+		{
+		}
+
+		Stream &operator=(Stream &&other)
+		{
+			m_stream = std::move(other.m_stream);
+			m_delimiters = std::move(other.m_delimiters);
+
+			return *this;
+		}
+
+		~Stream() = default;
+
+		void read(std::string streamName, std::istream &istream);
+		void read(const boost::filesystem::path &path);
+
+		void reset();
+		void seek(Position position);
+		Position position() const;
+		StreamCoordinate coordinate() const;
+
+		char currentCharacter() const;
+		void advance();
+		bool atEnd() const;
+
+		void check() const;
+
+	protected:
+		mutable std::stringstream m_stream;
+
+		std::vector<Delimiter> m_delimiters;
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}
+}
+
+#endif

include/plasp/utils/StreamCoordinate.h

@@ -1,27 +1,24 @@
-#ifndef __PLASP__PDDL__IDENTIFIER_H
-#define __PLASP__PDDL__IDENTIFIER_H
+#ifndef __PLASP__UTILS__STREAM_COORDINATE_H
+#define __PLASP__UTILS__STREAM_COORDINATE_H
 
-#include <cctype>
+#include <string>
 
 namespace plasp
 {
-namespace pddl
+namespace utils
 {
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 //
-// Identifier
+// StreamCoordinate
 //
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-const auto isIdentifier =
-	[](const auto character)
+struct StreamCoordinate
 {
-		return character != '?'
-			&& character != '('
-			&& character != ')'
-			&& character != ';'
-			&& std::isgraph(character);
+	std::string sectionName;
+	size_t row;
+	size_t column;
 };
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////

instances/ipc-1998-gripper/domain.pddl

@@ -0,0 +1,34 @@
+(define (domain gripper-strips)
+   (:predicates (room ?r)
+		(ball ?b)
+		(gripper ?g)
+		(at-robby ?r)
+		(at ?b ?r)
+		(free ?g)
+		(carry ?o ?g))
+
+   (:action move
+       :parameters  (?from ?to)
+       :precondition (and  (room ?from) (room ?to) (at-robby ?from))
+       :effect (and  (at-robby ?to)
+		     (not (at-robby ?from))))
+
+
+
+   (:action pick
+       :parameters (?obj ?room ?gripper)
+       :precondition  (and  (ball ?obj) (room ?room) (gripper ?gripper)
+			    (at ?obj ?room) (at-robby ?room) (free ?gripper))
+       :effect (and (carry ?obj ?gripper)
+		    (not (at ?obj ?room)) 
+		    (not (free ?gripper))))
+
+
+   (:action drop
+       :parameters  (?obj  ?room ?gripper)
+       :precondition  (and  (ball ?obj) (room ?room) (gripper ?gripper)
+			    (carry ?obj ?gripper) (at-robby ?room))
+       :effect (and (at ?obj ?room)
+		    (free ?gripper)
+		    (not (carry ?obj ?gripper)))))
+

instances/ipc-1998-gripper/problem-01.pddl

@@ -0,0 +1,22 @@
+(define (problem strips-gripper-x-1)
+   (:domain gripper-strips)
+   (:objects rooma roomb ball4 ball3 ball2 ball1 left right)
+   (:init (room rooma)
+          (room roomb)
+          (ball ball4)
+          (ball ball3)
+          (ball ball2)
+          (ball ball1)
+          (at-robby rooma)
+          (free left)
+          (free right)
+          (at ball4 rooma)
+          (at ball3 rooma)
+          (at ball2 rooma)
+          (at ball1 rooma)
+          (gripper left)
+          (gripper right))
+   (:goal (and (at ball4 roomb)
+               (at ball3 roomb)
+               (at ball2 roomb)
+               (at ball1 roomb))))

instances/ipc-1998-gripper/problem-02.pddl

@@ -0,0 +1,28 @@
+(define (problem strips-gripper-x-2)
+   (:domain gripper-strips)
+   (:objects rooma roomb ball6 ball5 ball4 ball3 ball2 ball1 left right)
+   (:init (room rooma)
+          (room roomb)
+          (ball ball6)
+          (ball ball5)
+          (ball ball4)
+          (ball ball3)
+          (ball ball2)
+          (ball ball1)
+          (at-robby rooma)
+          (free left)
+          (free right)
+          (at ball6 rooma)
+          (at ball5 rooma)
+          (at ball4 rooma)
+          (at ball3 rooma)
+          (at ball2 rooma)
+          (at ball1 rooma)
+          (gripper left)
+          (gripper right))
+   (:goal (and (at ball6 roomb)
+               (at ball5 roomb)
+               (at ball4 roomb)
+               (at ball3 roomb)
+               (at ball2 roomb)
+               (at ball1 roomb))))

instances/ipc-1998-gripper/solutions

@@ -0,0 +1,4 @@
+instance | minimal horizon | #solutions with minimal horizon
+============================================================
+problem-01.pddl | 11 | 384
+problem-02.pddl | 17 | 46080

instances/ipc-2000-blocks-track-1-typed/domain.pddl

@@ -0,0 +1,49 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; 4 Op-blocks world
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(define (domain BLOCKS)
+  (:requirements :strips :typing)
+  (:types block)
+  (:predicates (on ?x - block ?y - block)
+	       (ontable ?x - block)
+	       (clear ?x - block)
+	       (handempty)
+	       (holding ?x - block)
+	       )
+
+  (:action pick-up
+	     :parameters (?x - block)
+	     :precondition (and (clear ?x) (ontable ?x) (handempty))
+	     :effect
+	     (and (not (ontable ?x))
+		   (not (clear ?x))
+		   (not (handempty))
+		   (holding ?x)))
+
+  (:action put-down
+	     :parameters (?x - block)
+	     :precondition (holding ?x)
+	     :effect
+	     (and (not (holding ?x))
+		   (clear ?x)
+		   (handempty)
+		   (ontable ?x)))
+  (:action stack
+	     :parameters (?x - block ?y - block)
+	     :precondition (and (holding ?x) (clear ?y))
+	     :effect
+	     (and (not (holding ?x))
+		   (not (clear ?y))
+		   (clear ?x)
+		   (handempty)
+		   (on ?x ?y)))
+  (:action unstack
+	     :parameters (?x - block ?y - block)
+	     :precondition (and (on ?x ?y) (clear ?x) (handempty))
+	     :effect
+	     (and (holding ?x)
+		   (clear ?y)
+		   (not (clear ?x))
+		   (not (handempty))
+		   (not (on ?x ?y)))))

instances/ipc-2000-blocks-track-1-typed/problem-04-00.pddl

@@ -0,0 +1,7 @@
+(define (problem BLOCKS-4-0)
+(:domain BLOCKS)
+(:objects D B A C - block)
+(:INIT (CLEAR C) (CLEAR A) (CLEAR B) (CLEAR D) (ONTABLE C) (ONTABLE A)
+ (ONTABLE B) (ONTABLE D) (HANDEMPTY))
+(:goal (AND (ON D C) (ON C B) (ON B A)))
+)

instances/ipc-2000-blocks-track-1-typed/problem-05-01.pddl

@@ -0,0 +1,7 @@
+(define (problem BLOCKS-5-1)
+(:domain BLOCKS)
+(:objects A D C E B - block)
+(:INIT (CLEAR B) (CLEAR E) (CLEAR C) (ONTABLE D) (ONTABLE E) (ONTABLE C)
+ (ON B A) (ON A D) (HANDEMPTY))
+(:goal (AND (ON D C) (ON C B) (ON B A) (ON A E)))
+)

instances/ipc-2000-blocks-track-1-typed/problem-08-01.pddl

@@ -0,0 +1,7 @@
+(define (problem BLOCKS-8-1)
+(:domain BLOCKS)
+(:objects B A G C F D H E - block)
+(:INIT (CLEAR E) (CLEAR H) (CLEAR D) (CLEAR F) (ONTABLE C) (ONTABLE G)
+ (ONTABLE D) (ONTABLE F) (ON E C) (ON H A) (ON A B) (ON B G) (HANDEMPTY))
+(:goal (AND (ON C D) (ON D B) (ON B G) (ON G F) (ON F H) (ON H A) (ON A E)))
+)

instances/ipc-2000-blocks-track-1-typed/problem-09-02.pddl

@@ -0,0 +1,8 @@
+(define (problem BLOCKS-9-2)
+(:domain BLOCKS)
+(:objects B I C E D A G F H - block)
+(:INIT (CLEAR H) (CLEAR F) (ONTABLE G) (ONTABLE F) (ON H A) (ON A D) (ON D E)
+ (ON E C) (ON C I) (ON I B) (ON B G) (HANDEMPTY))
+(:goal (AND (ON F G) (ON G H) (ON H D) (ON D I) (ON I E) (ON E B) (ON B C)
+            (ON C A)))
+)

instances/ipc-2000-blocks-track-1-typed/solutions

@@ -0,0 +1,6 @@
+instance | minimal horizon | #solutions with minimal horizon
+============================================================
+problem-04-00.pddl | 6 | 1
+problem-05-01.pddl | 10 | 2
+problem-08-01.pddl | 20 | 60
+problem-09-02.pddl | 20 | 37

instances/ipc-2000-elevator-m10-strips/domain.pddl

@@ -0,0 +1,66 @@
+(define (domain miconic)
+  (:requirements :strips)
+  (:types passenger - object
+          floor - object
+         )
+
+(:predicates 
+(origin ?person - passenger ?floor - floor)
+;; entry of ?person is ?floor
+;; inertia
+
+(destin ?person - passenger ?floor - floor)
+;; exit of ?person is ?floor
+;; inertia
+
+(above ?floor1 - floor  ?floor2 - floor)
+;; ?floor2 is located above of ?floor1
+
+(boarded ?person - passenger)
+;; true if ?person has boarded the lift
+
+(not-boarded ?person - passenger)
+;; true if ?person has not boarded the lift
+
+(served ?person - passenger)
+;; true if ?person has alighted as her destination
+
+(not-served ?person - passenger)
+;; true if ?person is not at their destination
+
+(lift-at ?floor - floor)
+;; current position of the lift is at ?floor
+)
+
+
+;;stop and allow boarding
+
+(:action board
+  :parameters (?f - floor ?p - passenger)
+  :precondition (and (lift-at ?f) (origin ?p ?f))
+  :effect (boarded ?p))
+
+(:action depart
+  :parameters (?f - floor ?p - passenger)
+  :precondition (and (lift-at ?f) (destin ?p ?f)
+		     (boarded ?p))
+  :effect (and (not (boarded ?p))
+	       (served ?p)))
+;;drive up
+
+(:action up
+  :parameters (?f1 - floor ?f2 - floor)
+  :precondition (and (lift-at ?f1) (above ?f1 ?f2))
+  :effect (and (lift-at ?f2) (not (lift-at ?f1))))
+
+
+;;drive down
+
+(:action down
+  :parameters (?f1 - floor ?f2 - floor)
+  :precondition (and (lift-at ?f1) (above ?f2 ?f1))
+  :effect (and (lift-at ?f2) (not (lift-at ?f1))))
+)
+
+
+

instances/ipc-2000-elevator-m10-strips/problem-03-00.pddl

@@ -0,0 +1,58 @@
+
+
+
+(define (problem mixed-f6-p3-u0-v0-g0-a0-n0-A0-B0-N0-F0-r0)
+   (:domain miconic)
+   (:objects p0 p1 p2 - passenger
+             f0 f1 f2 f3 f4 f5 - floor)
+
+
+(:init
+(above f0 f1)
+(above f0 f2)
+(above f0 f3)
+(above f0 f4)
+(above f0 f5)
+
+(above f1 f2)
+(above f1 f3)
+(above f1 f4)
+(above f1 f5)
+
+(above f2 f3)
+(above f2 f4)
+(above f2 f5)
+
+(above f3 f4)
+(above f3 f5)
+
+(above f4 f5)
+
+
+
+(origin p0 f1)
+(destin p0 f4)
+
+(origin p1 f3)
+(destin p1 f1)
+
+(origin p2 f5)
+(destin p2 f1)
+
+
+
+
+
+
+(lift-at f0)
+)
+
+
+(:goal (and 
+(served p0)
+(served p1)
+(served p2)
+))
+)
+
+

instances/ipc-2000-elevator-m10-strips/problem-03-01.pddl

@@ -0,0 +1,58 @@
+
+
+
+(define (problem mixed-f6-p3-u0-v0-g0-a0-n0-A0-B0-N0-F0-r1)
+   (:domain miconic)
+   (:objects p0 p1 p2 - passenger
+             f0 f1 f2 f3 f4 f5 - floor)
+
+
+(:init
+(above f0 f1)
+(above f0 f2)
+(above f0 f3)
+(above f0 f4)
+(above f0 f5)
+
+(above f1 f2)
+(above f1 f3)
+(above f1 f4)
+(above f1 f5)
+
+(above f2 f3)
+(above f2 f4)
+(above f2 f5)
+
+(above f3 f4)
+(above f3 f5)
+
+(above f4 f5)
+
+
+
+(origin p0 f2)
+(destin p0 f5)
+
+(origin p1 f5)
+(destin p1 f2)
+
+(origin p2 f4)
+(destin p2 f1)
+
+
+
+
+
+
+(lift-at f0)
+)
+
+
+(:goal (and 
+(served p0)
+(served p1)
+(served p2)
+))
+)
+
+

instances/ipc-2000-elevator-m10-strips/problem-04-00.pddl

@@ -0,0 +1,77 @@
+
+
+
+(define (problem mixed-f8-p4-u0-v0-g0-a0-n0-A0-B0-N0-F0-r0)
+   (:domain miconic)
+   (:objects p0 p1 p2 p3 - passenger
+             f0 f1 f2 f3 f4 f5 f6 f7 - floor)
+
+
+(:init
+(above f0 f1)
+(above f0 f2)
+(above f0 f3)
+(above f0 f4)
+(above f0 f5)
+(above f0 f6)
+(above f0 f7)
+
+(above f1 f2)
+(above f1 f3)
+(above f1 f4)
+(above f1 f5)
+(above f1 f6)
+(above f1 f7)
+
+(above f2 f3)
+(above f2 f4)
+(above f2 f5)
+(above f2 f6)
+(above f2 f7)
+
+(above f3 f4)
+(above f3 f5)
+(above f3 f6)
+(above f3 f7)
+
+(above f4 f5)
+(above f4 f6)
+(above f4 f7)
+
+(above f5 f6)
+(above f5 f7)
+
+(above f6 f7)
+
+
+
+(origin p0 f7)
+(destin p0 f6)
+
+(origin p1 f1)
+(destin p1 f3)
+
+(origin p2 f1)
+(destin p2 f7)
+
+(origin p3 f2)
+(destin p3 f4)
+
+
+
+
+
+
+(lift-at f0)
+)
+
+
+(:goal (and 
+(served p0)
+(served p1)
+(served p2)
+(served p3)
+))
+)
+
+

instances/ipc-2000-elevator-m10-strips/problem-04-01.pddl

@@ -0,0 +1,77 @@
+
+
+
+(define (problem mixed-f8-p4-u0-v0-g0-a0-n0-A0-B0-N0-F0-r1)
+   (:domain miconic)
+   (:objects p0 p1 p2 p3 - passenger
+             f0 f1 f2 f3 f4 f5 f6 f7 - floor)
+
+
+(:init
+(above f0 f1)
+(above f0 f2)
+(above f0 f3)
+(above f0 f4)
+(above f0 f5)
+(above f0 f6)
+(above f0 f7)
+
+(above f1 f2)
+(above f1 f3)
+(above f1 f4)
+(above f1 f5)
+(above f1 f6)
+(above f1 f7)
+
+(above f2 f3)
+(above f2 f4)
+(above f2 f5)
+(above f2 f6)
+(above f2 f7)
+
+(above f3 f4)
+(above f3 f5)
+(above f3 f6)
+(above f3 f7)
+
+(above f4 f5)
+(above f4 f6)
+(above f4 f7)
+
+(above f5 f6)
+(above f5 f7)
+
+(above f6 f7)
+
+
+
+(origin p0 f0)
+(destin p0 f5)
+
+(origin p1 f7)
+(destin p1 f4)
+
+(origin p2 f0)
+(destin p2 f7)
+
+(origin p3 f1)
+(destin p3 f6)
+
+
+
+
+
+
+(lift-at f0)
+)
+
+
+(:goal (and 
+(served p0)
+(served p1)
+(served p2)
+(served p3)
+))
+)
+
+

instances/ipc-2000-elevator-m10-strips/solutions

@@ -0,0 +1,6 @@
+instance | minimal horizon | #solutions with minimal horizon
+============================================================
+problem-03-00.pddl | 10 | 12
+problem-03-01.pddl | 11 | 40
+problem-04-00.pddl | 14 | 180
+problem-04-01.pddl | 13 | 120

instances/ipc-2002-depots-strips/domain.pddl

@@ -0,0 +1,42 @@
+(define (domain Depot)
+(:requirements :typing)
+(:types place locatable - object
+	depot distributor - place
+        truck hoist surface - locatable
+        pallet crate - surface)
+
+(:predicates (at ?x - locatable ?y - place) 
+             (on ?x - crate ?y - surface)
+             (in ?x - crate ?y - truck)
+             (lifting ?x - hoist ?y - crate)
+             (available ?x - hoist)
+             (clear ?x - surface))
+	
+(:action Drive
+:parameters (?x - truck ?y - place ?z - place) 
+:precondition (and (at ?x ?y))
+:effect (and (not (at ?x ?y)) (at ?x ?z)))
+
+(:action Lift
+:parameters (?x - hoist ?y - crate ?z - surface ?p - place)
+:precondition (and (at ?x ?p) (available ?x) (at ?y ?p) (on ?y ?z) (clear ?y))
+:effect (and (not (at ?y ?p)) (lifting ?x ?y) (not (clear ?y)) (not (available ?x)) 
+             (clear ?z) (not (on ?y ?z))))
+
+(:action Drop 
+:parameters (?x - hoist ?y - crate ?z - surface ?p - place)
+:precondition (and (at ?x ?p) (at ?z ?p) (clear ?z) (lifting ?x ?y))
+:effect (and (available ?x) (not (lifting ?x ?y)) (at ?y ?p) (not (clear ?z)) (clear ?y)
+		(on ?y ?z)))
+
+(:action Load
+:parameters (?x - hoist ?y - crate ?z - truck ?p - place)
+:precondition (and (at ?x ?p) (at ?z ?p) (lifting ?x ?y))
+:effect (and (not (lifting ?x ?y)) (in ?y ?z) (available ?x)))
+
+(:action Unload 
+:parameters (?x - hoist ?y - crate ?z - truck ?p - place)
+:precondition (and (at ?x ?p) (at ?z ?p) (available ?x) (in ?y ?z))
+:effect (and (not (in ?y ?z)) (not (available ?x)) (lifting ?x ?y)))
+
+)

instances/ipc-2002-depots-strips/problem-01.pddl

@@ -0,0 +1,34 @@
+(define (problem depotprob1818) (:domain Depot)
+(:objects
+	depot0 - Depot
+	distributor0 distributor1 - Distributor
+	truck0 truck1 - Truck
+	pallet0 pallet1 pallet2 - Pallet
+	crate0 crate1 - Crate
+	hoist0 hoist1 hoist2 - Hoist)
+(:init
+	(at pallet0 depot0)
+	(clear crate1)
+	(at pallet1 distributor0)
+	(clear crate0)
+	(at pallet2 distributor1)
+	(clear pallet2)
+	(at truck0 distributor1)
+	(at truck1 depot0)
+	(at hoist0 depot0)
+	(available hoist0)
+	(at hoist1 distributor0)
+	(available hoist1)
+	(at hoist2 distributor1)
+	(available hoist2)
+	(at crate0 distributor0)
+	(on crate0 pallet1)
+	(at crate1 depot0)
+	(on crate1 pallet0)
+)
+
+(:goal (and
+		(on crate0 pallet2)
+		(on crate1 pallet1)
+	)
+))

instances/ipc-2002-depots-strips/problem-02.pddl

@@ -0,0 +1,40 @@
+(define (problem depotprob7512) (:domain Depot)
+(:objects
+	depot0 - Depot
+	distributor0 distributor1 - Distributor
+	truck0 truck1 - Truck
+	pallet0 pallet1 pallet2 - Pallet
+	crate0 crate1 crate2 crate3 - Crate
+	hoist0 hoist1 hoist2 - Hoist)
+(:init
+	(at pallet0 depot0)
+	(clear crate0)
+	(at pallet1 distributor0)
+	(clear crate3)
+	(at pallet2 distributor1)
+	(clear crate2)
+	(at truck0 depot0)
+	(at truck1 depot0)
+	(at hoist0 depot0)
+	(available hoist0)
+	(at hoist1 distributor0)
+	(available hoist1)
+	(at hoist2 distributor1)
+	(available hoist2)
+	(at crate0 depot0)
+	(on crate0 pallet0)
+	(at crate1 distributor1)
+	(on crate1 pallet2)
+	(at crate2 distributor1)
+	(on crate2 crate1)
+	(at crate3 distributor0)
+	(on crate3 pallet1)
+)
+
+(:goal (and
+		(on crate0 pallet2)
+		(on crate1 crate3)
+		(on crate2 pallet0)
+		(on crate3 pallet1)
+	)
+))

instances/ipc-2002-depots-strips/solutions

@@ -0,0 +1,4 @@
+instance | minimal horizon | #solutions with minimal horizon
+============================================================
+problem-01.pddl | 10 | 16
+problem-02.pddl | 15 | 448

instances/ipc-2002-driver-log-strips/domain.pddl

@@ -0,0 +1,79 @@
+(define (domain driverlog)
+  (:requirements :typing) 
+  (:types         location locatable - object
+		driver truck obj - locatable
+  
+  )
+  (:predicates 
+		(at ?obj - locatable ?loc - location)
+		(in ?obj1 - obj ?obj - truck)
+		(driving ?d - driver ?v - truck)
+		(link ?x ?y - location) (path ?x ?y - location)
+		(empty ?v - truck)
+)
+
+
+(:action LOAD-TRUCK
+  :parameters
+   (?obj - obj
+    ?truck - truck
+    ?loc - location)
+  :precondition
+   (and (at ?truck ?loc) (at ?obj ?loc))
+  :effect
+   (and (not (at ?obj ?loc)) (in ?obj ?truck)))
+
+(:action UNLOAD-TRUCK
+  :parameters
+   (?obj - obj
+    ?truck - truck
+    ?loc - location)
+  :precondition
+   (and (at ?truck ?loc) (in ?obj ?truck))
+  :effect
+   (and (not (in ?obj ?truck)) (at ?obj ?loc)))
+
+(:action BOARD-TRUCK
+  :parameters
+   (?driver - driver
+    ?truck - truck
+    ?loc - location)
+  :precondition
+   (and (at ?truck ?loc) (at ?driver ?loc) (empty ?truck))
+  :effect
+   (and (not (at ?driver ?loc)) (driving ?driver ?truck) (not (empty ?truck))))
+
+(:action DISEMBARK-TRUCK
+  :parameters
+   (?driver - driver
+    ?truck - truck
+    ?loc - location)
+  :precondition
+   (and (at ?truck ?loc) (driving ?driver ?truck))
+  :effect
+   (and (not (driving ?driver ?truck)) (at ?driver ?loc) (empty ?truck)))
+
+(:action DRIVE-TRUCK
+  :parameters
+   (?truck - truck
+    ?loc-from - location
+    ?loc-to - location
+    ?driver - driver)
+  :precondition
+   (and (at ?truck ?loc-from)
+   (driving ?driver ?truck) (link ?loc-from ?loc-to))
+  :effect
+   (and (not (at ?truck ?loc-from)) (at ?truck ?loc-to)))
+
+(:action WALK
+  :parameters
+   (?driver - driver
+    ?loc-from - location
+    ?loc-to - location)
+  :precondition
+   (and (at ?driver ?loc-from) (path ?loc-from ?loc-to))
+  :effect
+   (and (not (at ?driver ?loc-from)) (at ?driver ?loc-to)))
+
+ 
+)

instances/ipc-2002-driver-log-strips/problem-01.pddl

@@ -0,0 +1,48 @@
+(define (problem DLOG-2-2-2)
+	(:domain driverlog)
+	(:objects
+	driver1 - driver
+	driver2 - driver
+	truck1 - truck
+	truck2 - truck
+	package1 - obj
+	package2 - obj
+	s0 - location
+	s1 - location
+	s2 - location
+	p1-0 - location
+	p1-2 - location
+	)
+	(:init
+	(at driver1 s2)
+	(at driver2 s2)
+	(at truck1 s0)
+	(empty truck1)
+	(at truck2 s0)
+	(empty truck2)
+	(at package1 s0)
+	(at package2 s0)
+	(path s1 p1-0)
+	(path p1-0 s1)
+	(path s0 p1-0)
+	(path p1-0 s0)
+	(path s1 p1-2)
+	(path p1-2 s1)
+	(path s2 p1-2)
+	(path p1-2 s2)
+	(link s0 s1)
+	(link s1 s0)
+	(link s0 s2)
+	(link s2 s0)
+	(link s2 s1)
+	(link s1 s2)
+)
+	(:goal (and
+	(at driver1 s1)
+	(at truck1 s1)
+	(at package1 s0)
+	(at package2 s0)
+	))
+
+
+)

instances/ipc-2002-driver-log-strips/problem-03.pddl

@@ -0,0 +1,59 @@
+(define (problem DLOG-2-2-4)
+	(:domain driverlog)
+	(:objects
+	driver1 - driver
+	driver2 - driver
+	truck1 - truck
+	truck2 - truck
+	package1 - obj
+	package2 - obj
+	package3 - obj
+	package4 - obj
+	s0 - location
+	s1 - location
+	s2 - location
+	p0-1 - location
+	p2-0 - location
+	p2-1 - location
+	)
+	(:init
+	(at driver1 s1)
+	(at driver2 s0)
+	(at truck1 s1)
+	(empty truck1)
+	(at truck2 s2)
+	(empty truck2)
+	(at package1 s0)
+	(at package2 s0)
+	(at package3 s1)
+	(at package4 s1)
+	(path s0 p0-1)
+	(path p0-1 s0)
+	(path s1 p0-1)
+	(path p0-1 s1)
+	(path s2 p2-0)
+	(path p2-0 s2)
+	(path s0 p2-0)
+	(path p2-0 s0)
+	(path s2 p2-1)
+	(path p2-1 s2)
+	(path s1 p2-1)
+	(path p2-1 s1)
+	(link s1 s0)
+	(link s0 s1)
+	(link s1 s2)
+	(link s2 s1)
+	(link s2 s0)
+	(link s0 s2)
+)
+	(:goal (and
+	(at driver2 s2)
+	(at truck1 s1)
+	(at truck2 s2)
+	(at package1 s1)
+	(at package2 s1)
+	(at package3 s2)
+	))
+
+
+)

instances/ipc-2002-driver-log-strips/solutions

@@ -0,0 +1,4 @@
+instance | minimal horizon | #solutions with minimal horizon
+============================================================
+problem-01.pddl | 7 | 1
+problem-03.pddl | 12 | 1056

instances/ipc-2004-satellite/domain.pddl

@@ -0,0 +1,75 @@
+
+(define (domain satellite)
+  (:requirements :strips :equality :typing)
+  (:types satellite direction instrument mode)
+ (:predicates 
+               (on_board ?i - instrument ?s - satellite)
+	       (supports ?i - instrument ?m - mode)
+	       (pointing ?s - satellite ?d - direction)
+	       (power_avail ?s - satellite)
+	       (power_on ?i - instrument)
+	       (calibrated ?i - instrument)
+	       (have_image ?d - direction ?m - mode)
+	       (calibration_target ?i - instrument ?d - direction))
+ 
+ 
+
+  (:action turn_to
+   :parameters (?s - satellite ?d_new - direction ?d_prev - direction)
+   :precondition (and (pointing ?s ?d_prev)
+              )
+   :effect (and  (pointing ?s ?d_new)
+                 (not (pointing ?s ?d_prev))
+           )
+  )
+
+ 
+  (:action switch_on
+   :parameters (?i - instrument ?s - satellite)
+ 
+   :precondition (and (on_board ?i ?s) 
+                      (power_avail ?s)
+                 )
+   :effect (and (power_on ?i)
+                (not (calibrated ?i))
+                (not (power_avail ?s))
+           )
+          
+  )
+
+ 
+  (:action switch_off
+   :parameters (?i - instrument ?s - satellite)
+ 
+   :precondition (and (on_board ?i ?s)
+                      (power_on ?i) 
+                  )
+   :effect (and (not (power_on ?i))
+                (power_avail ?s)
+           )
+  )
+
+  (:action calibrate
+   :parameters (?s - satellite ?i - instrument ?d - direction)
+   :precondition (and (on_board ?i ?s)
+		      (calibration_target ?i ?d)
+                      (pointing ?s ?d)
+                      (power_on ?i)
+                  )
+   :effect (calibrated ?i)
+  )
+
+
+  (:action take_image
+   :parameters (?s - satellite ?d - direction ?i - instrument ?m - mode)
+   :precondition (and (calibrated ?i)
+                      (on_board ?i ?s)
+                      (supports ?i ?m)
+                      (power_on ?i)
+                      (pointing ?s ?d)
+                      (power_on ?i)
+               )
+   :effect (have_image ?d ?m)
+  )
+)
+

instances/ipc-2004-satellite/problem-01.pddl

@@ -0,0 +1,30 @@
+(define (problem strips-sat-x-1)
+(:domain satellite)
+(:objects
+	satellite0 - satellite
+	instrument0 - instrument
+	image1 - mode
+	spectrograph2 - mode
+	thermograph0 - mode
+	Star0 - direction
+	GroundStation1 - direction
+	GroundStation2 - direction
+	Phenomenon3 - direction
+	Phenomenon4 - direction
+	Star5 - direction
+	Phenomenon6 - direction
+)
+(:init
+	(supports instrument0 thermograph0)
+	(calibration_target instrument0 GroundStation2)
+	(on_board instrument0 satellite0)
+	(power_avail satellite0)
+	(pointing satellite0 Phenomenon6)
+)
+(:goal (and
+	(have_image Phenomenon4 thermograph0)
+	(have_image Star5 thermograph0)
+	(have_image Phenomenon6 thermograph0)
+))
+
+)

instances/ipc-2004-satellite/problem-02.pddl

@@ -0,0 +1,40 @@
+(define (problem strips-sat-x-1)
+(:domain satellite)
+(:objects
+	satellite0 - satellite
+	instrument0 - instrument
+	instrument1 - instrument
+	infrared0 - mode
+	infrared1 - mode
+	image2 - mode
+	GroundStation1 - direction
+	Star0 - direction
+	GroundStation2 - direction
+	Planet3 - direction
+	Planet4 - direction
+	Phenomenon5 - direction
+	Phenomenon6 - direction
+	Star7 - direction
+)
+(:init
+	(supports instrument0 infrared1)
+	(supports instrument0 infrared0)
+	(calibration_target instrument0 Star0)
+	(supports instrument1 image2)
+	(supports instrument1 infrared1)
+	(supports instrument1 infrared0)
+	(calibration_target instrument1 GroundStation2)
+	(on_board instrument0 satellite0)
+	(on_board instrument1 satellite0)
+	(power_avail satellite0)
+	(pointing satellite0 Planet4)
+)
+(:goal (and
+	(have_image Planet3 infrared0)
+	(have_image Planet4 infrared0)
+	(have_image Phenomenon5 image2)
+	(have_image Phenomenon6 infrared0)
+	(have_image Star7 infrared0)
+))
+
+)

instances/ipc-2004-satellite/problem-03.pddl

@@ -0,0 +1,52 @@
+(define (problem strips-sat-x-1)
+(:domain satellite)
+(:objects
+	satellite0 - satellite
+	instrument0 - instrument
+	instrument1 - instrument
+	instrument2 - instrument
+	satellite1 - satellite
+	instrument3 - instrument
+	image1 - mode
+	infrared0 - mode
+	spectrograph2 - mode
+	Star1 - direction
+	Star2 - direction
+	Star0 - direction
+	Star3 - direction
+	Star4 - direction
+	Phenomenon5 - direction
+	Phenomenon6 - direction
+	Phenomenon7 - direction
+)
+(:init
+	(supports instrument0 spectrograph2)
+	(supports instrument0 infrared0)
+	(calibration_target instrument0 Star1)
+	(supports instrument1 image1)
+	(calibration_target instrument1 Star2)
+	(supports instrument2 infrared0)
+	(supports instrument2 image1)
+	(calibration_target instrument2 Star0)
+	(on_board instrument0 satellite0)
+	(on_board instrument1 satellite0)
+	(on_board instrument2 satellite0)
+	(power_avail satellite0)
+	(pointing satellite0 Star4)
+	(supports instrument3 spectrograph2)
+	(supports instrument3 infrared0)
+	(supports instrument3 image1)
+	(calibration_target instrument3 Star0)
+	(on_board instrument3 satellite1)
+	(power_avail satellite1)
+	(pointing satellite1 Star0)
+)
+(:goal (and
+	(pointing satellite0 Phenomenon5)
+	(have_image Star3 infrared0)
+	(have_image Star4 spectrograph2)
+	(have_image Phenomenon5 spectrograph2)
+	(have_image Phenomenon7 spectrograph2)
+))
+
+)

instances/ipc-2004-satellite/solutions

@@ -0,0 +1,5 @@
+instance | minimal horizon | #solutions with minimal horizon
+============================================================
+problem-01.pddl | 9 | 12
+problem-02.pddl | 13 | 240
+problem-03.pddl | 11 | 276

instances/ipc-2006-tpp-propositional/domain.pddl

@@ -0,0 +1,65 @@
+; IPC5 Domain: TPP Propositional
+; Authors: Alfonso Gerevini and Alessandro Saetti 
+
+(define (domain TPP-Propositional)
+(:requirements :strips :typing)
+(:types place locatable level - object
+	depot market - place
+	truck goods - locatable)
+
+(:predicates (loaded ?g - goods ?t - truck ?l - level)
+	     (ready-to-load ?g - goods ?m - market ?l - level) 
+	     (stored ?g - goods ?l - level) 
+	     (on-sale ?g - goods ?m -  market ?l - level)
+	     (next ?l1 ?l2 - level)
+	     (at ?t - truck ?p - place)
+	     (connected ?p1 ?p2 - place))
+
+(:action drive
+ :parameters (?t - truck ?from ?to - place)
+ :precondition (and (at ?t ?from) (connected ?from ?to))
+ :effect (and (not (at ?t ?from)) (at ?t ?to)))
+
+
+; ### LOAD ###
+; ?l1 is the level of ?g ready to be loaded at ?m before loading
+; ?l2 is the level of ?g ready to be loaded at ?m after loading
+; ?l3 is the level of ?g in ?t before loading
+; ?l4 is the level of ?g in ?t after loading
+
+(:action load
+ :parameters (?g - goods ?t - truck ?m - market ?l1 ?l2 ?l3 ?l4 - level)
+ :precondition (and (at ?t ?m) (loaded ?g ?t ?l3)
+		    (ready-to-load ?g ?m ?l2) (next ?l2 ?l1) (next ?l4 ?l3))
+ :effect (and (loaded ?g ?t ?l4) (not (loaded ?g ?t ?l3)) 
+	      (ready-to-load ?g ?m ?l1) (not (ready-to-load ?g ?m ?l2))))
+
+
+; ### UNLOAD ###
+; ?l1 is the level of ?g in ?t before unloading
+; ?l2 is the level of ?g in ?t after unloading
+; ?l3 is the level of ?g in ?d before unloading
+; ?l4 is the level of ?g in ?d after unloading
+
+(:action unload
+ :parameters (?g - goods ?t - truck ?d - depot ?l1 ?l2 ?l3 ?l4 - level)
+ :precondition (and (at ?t ?d) (loaded ?g ?t ?l2)
+		    (stored ?g ?l3) (next ?l2 ?l1) (next ?l4 ?l3))
+ :effect (and (loaded ?g ?t ?l1) (not (loaded ?g ?t ?l2)) 
+	      (stored ?g ?l4) (not (stored ?g ?l3))))
+
+
+; ### BUY ###
+; ?l1 is the level of ?g on sale at ?m before buying
+; ?l2 is the level of ?g on sale at ?m after buying 
+; ?l3 is the level of ?g ready to be loaded at ?m before buying
+; ?l4 is the level of ?g ready to be loaded at ?m after buying
+
+(:action buy
+ :parameters (?t - truck ?g - goods ?m - market ?l1 ?l2 ?l3 ?l4 - level)
+ :precondition (and (at ?t ?m) (on-sale ?g ?m ?l2) (ready-to-load ?g ?m ?l3)
+		    (next ?l2 ?l1) (next ?l4 ?l3))
+ :effect (and (on-sale ?g ?m ?l1) (not (on-sale ?g ?m ?l2)) 
+	      (ready-to-load ?g ?m ?l4) (not (ready-to-load ?g ?m ?l3))))
+
+)

instances/ipc-2006-tpp-propositional/problem-02.pddl

@@ -0,0 +1,28 @@
+(define (problem TPP)
+(:domain TPP-Propositional)
+(:objects
+	goods1 goods2 - goods
+	truck1 - truck
+	market1 - market
+	depot1 - depot
+	level0 level1 - level)
+
+(:init
+	(next level1 level0)
+	(ready-to-load goods1 market1 level0)
+	(ready-to-load goods2 market1 level0)
+	(stored goods1 level0)
+	(stored goods2 level0)
+	(loaded goods1 truck1 level0)
+	(loaded goods2 truck1 level0)
+	(connected depot1 market1)
+	(connected market1 depot1)
+	(on-sale goods1 market1 level1)
+	(on-sale goods2 market1 level1)
+	(at truck1 depot1))
+
+(:goal (and
+	(stored goods1 level1)
+	(stored goods2 level1)))
+
+)

instances/ipc-2006-tpp-propositional/problem-03.pddl

@@ -0,0 +1,33 @@
+(define (problem TPP)
+(:domain TPP-Propositional)
+(:objects
+	goods1 goods2 goods3 - goods
+	truck1 - truck
+	market1 - market
+	depot1 - depot
+	level0 level1 - level)
+
+(:init
+	(next level1 level0)
+	(ready-to-load goods1 market1 level0)
+	(ready-to-load goods2 market1 level0)
+	(ready-to-load goods3 market1 level0)
+	(stored goods1 level0)
+	(stored goods2 level0)
+	(stored goods3 level0)
+	(loaded goods1 truck1 level0)
+	(loaded goods2 truck1 level0)
+	(loaded goods3 truck1 level0)
+	(connected depot1 market1)
+	(connected market1 depot1)
+	(on-sale goods1 market1 level1)
+	(on-sale goods2 market1 level1)
+	(on-sale goods3 market1 level1)
+	(at truck1 depot1))
+
+(:goal (and
+	(stored goods1 level1)
+	(stored goods2 level1)
+	(stored goods3 level1)))
+
+)

instances/ipc-2006-tpp-propositional/problem-04.pddl

@@ -0,0 +1,38 @@
+(define (problem TPP)
+(:domain TPP-Propositional)
+(:objects
+	goods1 goods2 goods3 goods4 - goods
+	truck1 - truck
+	market1 - market
+	depot1 - depot
+	level0 level1 - level)
+
+(:init
+	(next level1 level0)
+	(ready-to-load goods1 market1 level0)
+	(ready-to-load goods2 market1 level0)
+	(ready-to-load goods3 market1 level0)
+	(ready-to-load goods4 market1 level0)
+	(stored goods1 level0)
+	(stored goods2 level0)
+	(stored goods3 level0)
+	(stored goods4 level0)
+	(loaded goods1 truck1 level0)
+	(loaded goods2 truck1 level0)
+	(loaded goods3 truck1 level0)
+	(loaded goods4 truck1 level0)
+	(connected depot1 market1)
+	(connected market1 depot1)
+	(on-sale goods1 market1 level1)
+	(on-sale goods2 market1 level1)
+	(on-sale goods3 market1 level1)
+	(on-sale goods4 market1 level1)
+	(at truck1 depot1))
+
+(:goal (and
+	(stored goods1 level1)
+	(stored goods2 level1)
+	(stored goods3 level1)
+	(stored goods4 level1)))
+
+)

instances/ipc-2006-tpp-propositional/solutions

@@ -0,0 +1,5 @@
+instance | minimal horizon | #solutions with minimal horizon
+============================================================
+problem-02.pddl | 8 | 12
+problem-03.pddl | 11 | 540
+problem-04.pddl | 14 | 60480

src/plasp/pddl/Action.cpp

@@ -5,10 +5,7 @@
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Domain.h>
 #include <plasp/pddl/ExpressionContext.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/expressions/Type.h>
-#include <plasp/utils/IO.h>
-#include <plasp/utils/ParserException.h>
 
 namespace plasp
 {
@@ -23,31 +20,33 @@ namespace pddl
 
 void Action::parseDeclaration(Context &context, Domain &domain)
 {
+	auto &parser = context.parser;
+
 	auto action = std::make_unique<Action>(Action());
 
-	action->m_name = context.parser.parseIdentifier(isIdentifier);
+	action->m_name = parser.parseIdentifier();
 
-	context.parser.expect<std::string>(":parameters");
-	context.parser.expect<std::string>("(");
+	parser.expect<std::string>(":parameters");
+	parser.expect<std::string>("(");
 
 	ExpressionContext expressionContext(domain, action->m_parameters);
 
 	// Read parameters
 	expressions::Variable::parseTypedDeclarations(context, expressionContext);
 
-	context.parser.expect<std::string>(")");
+	parser.expect<std::string>(")");
 
 	// Parse preconditions and effects
-	while (context.parser.currentCharacter() != ')')
+	while (!parser.testAndReturn(')'))
 	{
-		context.parser.expect<std::string>(":");
+		parser.expect<std::string>(":");
 
-		if (context.parser.probeIdentifier("precondition", isIdentifier))
+		if (parser.testIdentifierAndSkip("precondition"))
 			action->m_precondition = parsePreconditionExpression(context, expressionContext);
-		else if (context.parser.probeIdentifier("effect", isIdentifier))
+		else if (parser.testIdentifierAndSkip("effect"))
 			action->m_effect = parseEffectExpression(context, expressionContext);
 
-		context.parser.skipWhiteSpace();
+		parser.skipWhiteSpace();
 	}
 
 	// Store new action
@@ -88,5 +87,13 @@ const Expression *Action::effect() const
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+void Action::normalizeParameterNames()
+{
+	for (size_t i = 0; i < m_parameters.size(); i++)
+		m_parameters[i]->setName("X" + std::to_string(i));
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 }
 }

src/plasp/pddl/Description.cpp

@@ -44,7 +44,7 @@ Description Description::fromStream(std::istream &istream)
 {
 	Description description;
 
-	description.m_context.parser.readStream("std::cin", istream);
+	description.m_context.parser.read("std::cin", istream);
 	description.parse();
 
 	return description;
@@ -56,7 +56,7 @@ Description Description::fromFile(const std::string &path)
 {
 	Description description;
 
-	description.m_context.parser.readFile(path);
+	description.m_context.parser.read(path);
 	description.parse();
 
 	return description;
@@ -73,7 +73,7 @@ Description Description::fromFiles(const std::vector<std::string> &paths)
 	std::for_each(paths.cbegin(), paths.cend(),
 		[&](const auto &path)
 		{
-			description.m_context.parser.readFile(path);
+			description.m_context.parser.read(path);
 		});
 
 	description.parse();
@@ -126,7 +126,6 @@ void Description::parse()
 {
 	auto &parser = m_context.parser;
 
-	parser.setCaseSensitive(false);
 	parser.removeComments(";", "\n", false);
 
 	// First, determine the locations of domain and problem
@@ -155,7 +154,7 @@ void Description::findSections()
 
 	parser.skipWhiteSpace();
 
-	while (!parser.atEndOfStream())
+	while (!parser.atEnd())
 	{
 		const auto position = parser.position();
 
@@ -163,20 +162,20 @@ void Description::findSections()
 		parser.expect<std::string>("define");
 		parser.expect<std::string>("(");
 
-		if (parser.probe<std::string>("domain"))
+		if (parser.testAndSkip<std::string>("domain"))
 		{
 			if (m_domainPosition != -1)
-				throw utils::ParserException(parser, "PDDL description may not contain two domains");
+				throw utils::ParserException(parser.coordinate(), "PDDL description may not contain two domains");
 
 			m_domainPosition = position;
 
 			parser.seek(position);
 			m_domain->findSections();
 		}
-		else if (m_context.parser.probe<std::string>("problem"))
+		else if (m_context.parser.testAndSkip<std::string>("problem"))
 		{
 			if (m_problemPosition != -1)
-				throw utils::ParserException(parser, "PDDL description may currently not contain two problems");
+				throw utils::ParserException(parser.coordinate(), "PDDL description may currently not contain two problems");
 
 			m_problem = std::make_unique<Problem>(Problem(m_context, *m_domain));
 
@@ -188,7 +187,7 @@ void Description::findSections()
 		else
 		{
 			const auto sectionIdentifier = parser.parse<std::string>();
-			throw utils::ParserException(parser, "unknown PDDL section “" + sectionIdentifier + "”");
+			throw utils::ParserException(parser.coordinate(), "unknown PDDL section “" + sectionIdentifier + "”");
 		}
 
 		m_context.parser.skipWhiteSpace();
@@ -205,5 +204,12 @@ void Description::checkConsistency()
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+void Description::normalizeParameterNames()
+{
+	m_domain->normalizeParameterNames();
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 }
 }

src/plasp/pddl/Domain.cpp

@@ -3,13 +3,11 @@
 #include <algorithm>
 
 #include <plasp/pddl/ConsistencyException.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/IO.h>
 #include <plasp/pddl/expressions/Constant.h>
 #include <plasp/pddl/expressions/PredicateDeclaration.h>
 #include <plasp/pddl/expressions/PrimitiveType.h>
 #include <plasp/pddl/expressions/Variable.h>
-#include <plasp/utils/IO.h>
 #include <plasp/utils/ParserException.h>
 
 namespace plasp
@@ -43,7 +41,7 @@ void Domain::findSections()
 	parser.expect<std::string>("(");
 	parser.expect<std::string>("domain");
 
-	m_name = m_context.parser.parseIdentifier(isIdentifier);
+	m_name = m_context.parser.parseIdentifier();
 
 	parser.expect<std::string>(")");
 
@@ -53,7 +51,7 @@ void Domain::findSections()
 			if (unique && sectionPosition != -1)
 			{
 				parser.seek(value);
-				throw utils::ParserException(parser, "only one “:" + sectionName + "” section allowed");
+				throw utils::ParserException(parser.coordinate(), "only one “:" + sectionName + "” section allowed");
 			}
 
 			sectionPosition = value;
@@ -72,38 +70,38 @@ void Domain::findSections()
 		const auto sectionIdentifierPosition = parser.position();
 
 		// Save the parser position of the individual sections for later parsing
-		if (parser.probeIdentifier("requirements", isIdentifier))
+		if (parser.testIdentifierAndSkip("requirements"))
 			setSectionPosition("requirements", m_requirementsPosition, position, true);
-		else if (parser.probeIdentifier("types", isIdentifier))
+		else if (parser.testIdentifierAndSkip("types"))
 			setSectionPosition("types", m_typesPosition, position, true);
-		else if (parser.probeIdentifier("constants", isIdentifier))
+		else if (parser.testIdentifierAndSkip("constants"))
 			setSectionPosition("constants", m_constantsPosition, position, true);
-		else if (parser.probeIdentifier("predicates", isIdentifier))
+		else if (parser.testIdentifierAndSkip("predicates"))
 			setSectionPosition("predicates", m_predicatesPosition, position, true);
-		else if (parser.probeIdentifier("action", isIdentifier))
+		else if (parser.testIdentifierAndSkip("action"))
 		{
 			m_actionPositions.emplace_back(-1);
 			setSectionPosition("action", m_actionPositions.back(), position);
 		}
-		else if (parser.probeIdentifier("functions", isIdentifier)
-			|| parser.probeIdentifier("constraints", isIdentifier)
-			|| parser.probeIdentifier("durative-action", isIdentifier)
-			|| parser.probeIdentifier("derived", isIdentifier))
+		else if (parser.testIdentifierAndSkip("functions")
+			|| parser.testIdentifierAndSkip("constraints")
+			|| parser.testIdentifierAndSkip("durative-action")
+			|| parser.testIdentifierAndSkip("derived"))
 		{
 			parser.seek(sectionIdentifierPosition);
 
-			const auto sectionIdentifier = parser.parseIdentifier(isIdentifier);
+			const auto sectionIdentifier = parser.parseIdentifier();
 
-			m_context.logger.logWarning(parser, "section type “" + sectionIdentifier + "” currently unsupported");
+			m_context.logger.logWarning(parser.coordinate(), "section type “" + sectionIdentifier + "” currently unsupported");
 
 			parser.seek(sectionIdentifierPosition);
 		}
 		else
 		{
-			const auto sectionIdentifier = parser.parseIdentifier(isIdentifier);
+			const auto sectionIdentifier = parser.parseIdentifier();
 
 			parser.seek(position);
-			throw utils::ParserException(m_context.parser, "unknown domain section “" + sectionIdentifier + "”");
+			throw utils::ParserException(parser.coordinate(), "unknown domain section “" + sectionIdentifier + "”");
 		}
 
 		// Skip section for now and parse it later
@@ -274,12 +272,14 @@ bool Domain::hasRequirement(Requirement::Type requirementType) const
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-void Domain::checkRequirement(Requirement::Type requirementType) const
+void Domain::checkRequirement(Requirement::Type requirementType)
 {
 	if (hasRequirement(requirementType))
 		return;
 
-	throw ConsistencyException("requirement “" + Requirement(requirementType).toPDDL() + "” used but never declared");
+	m_context.logger.logWarning(m_context.parser.coordinate(), "requirement “" + Requirement(requirementType).toPDDL() + "” used but never declared");
+
+	m_requirements.push_back(requirementType);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -340,7 +340,7 @@ void Domain::parseTypeSection()
 	while (parser.currentCharacter() != ')')
 	{
 		if (parser.currentCharacter() == '(')
-			throw utils::ParserException(parser, "only primitive types are allowed in type section");
+			throw utils::ParserException(parser.coordinate(), "only primitive types are allowed in type section");
 
 		expressions::PrimitiveType::parseTypedDeclaration(m_context, *this);
 
@@ -415,5 +415,22 @@ void Domain::checkConsistency()
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+void Domain::normalizeParameterNames()
+{
+	std::for_each(m_predicates.begin(), m_predicates.end(),
+		[](auto &predicate)
+		{
+			predicate->normalizeParameterNames();
+		});
+
+	std::for_each(m_actions.begin(), m_actions.end(),
+		[](auto &action)
+		{
+			action->normalizeParameterNames();
+		});
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 }
 }

src/plasp/pddl/Expression.cpp

@@ -3,7 +3,6 @@
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Domain.h>
 #include <plasp/pddl/ExpressionContext.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/IO.h>
 #include <plasp/pddl/expressions/And.h>
 #include <plasp/pddl/expressions/Imply.h>
@@ -12,7 +11,6 @@
 #include <plasp/pddl/expressions/Predicate.h>
 #include <plasp/pddl/expressions/PredicateDeclaration.h>
 #include <plasp/pddl/expressions/Unsupported.h>
-#include <plasp/utils/IO.h>
 #include <plasp/utils/ParserException.h>
 
 namespace plasp
@@ -49,12 +47,12 @@ ExpressionPointer parsePreconditionExpression(Context &context,
 
 	const auto expressionIdentifierPosition = parser.position();
 
-	if (parser.probeIdentifier("forall", isIdentifier)
-		|| parser.probeIdentifier("preference", isIdentifier))
+	if (parser.testIdentifierAndSkip("forall")
+		|| parser.testIdentifierAndSkip("preference"))
 	{
 		// TODO: refactor
 		parser.seek(expressionIdentifierPosition);
-		const auto expressionIdentifier = parser.parseIdentifier(isIdentifier);
+		const auto expressionIdentifier = parser.parseIdentifier();
 
 		parser.seek(position);
 		return expressions::Unsupported::parse(context);
@@ -89,32 +87,32 @@ ExpressionPointer parseExpression(Context &context, ExpressionContext &expressio
 
 	const auto expressionIdentifierPosition = parser.position();
 
-	if (parser.probeIdentifier("exists", isIdentifier)
-		|| parser.probeIdentifier("forall", isIdentifier)
-		|| parser.probeIdentifier("-", isIdentifier)
-		|| parser.probeIdentifier("=", isIdentifier)
-		|| parser.probeIdentifier("*", isIdentifier)
-		|| parser.probeIdentifier("+", isIdentifier)
-		|| parser.probeIdentifier("-", isIdentifier)
-		|| parser.probeIdentifier("/", isIdentifier)
-		|| parser.probeIdentifier(">", isIdentifier)
-		|| parser.probeIdentifier("<", isIdentifier)
-		|| parser.probeIdentifier("=", isIdentifier)
-		|| parser.probeIdentifier(">=", isIdentifier)
-		|| parser.probeIdentifier("<=", isIdentifier))
+	if (parser.testIdentifierAndSkip("exists")
+		|| parser.testIdentifierAndSkip("forall")
+		|| parser.testIdentifierAndSkip("-")
+		|| parser.testIdentifierAndSkip("=")
+		|| parser.testIdentifierAndSkip("*")
+		|| parser.testIdentifierAndSkip("+")
+		|| parser.testIdentifierAndSkip("-")
+		|| parser.testIdentifierAndSkip("/")
+		|| parser.testIdentifierAndSkip(">")
+		|| parser.testIdentifierAndSkip("<")
+		|| parser.testIdentifierAndSkip("=")
+		|| parser.testIdentifierAndSkip(">=")
+		|| parser.testIdentifierAndSkip("<="))
 	{
 		parser.seek(expressionIdentifierPosition);
-		const auto expressionIdentifier = parser.parseIdentifier(isIdentifier);
+		const auto expressionIdentifier = parser.parseIdentifier();
 
 		parser.seek(position);
 		return expressions::Unsupported::parse(context);
 	}
 
 	parser.seek(expressionIdentifierPosition);
-	const auto expressionIdentifier = parser.parseIdentifier(isIdentifier);
+	const auto expressionIdentifier = parser.parseIdentifier();
 
 	parser.seek(position);
-	throw utils::ParserException(context.parser, "expression type “" + expressionIdentifier + "” unknown or not allowed in this context");
+	throw utils::ParserException(parser.coordinate(), "expression type “" + expressionIdentifier + "” unknown or not allowed in this context");
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -134,11 +132,11 @@ ExpressionPointer parseEffectExpression(Context &context, ExpressionContext &exp
 
 	const auto expressionIdentifierPosition = parser.position();
 
-	if (parser.probeIdentifier("forall", isIdentifier)
-		|| parser.probeIdentifier("when", isIdentifier))
+	if (parser.testIdentifierAndSkip("forall")
+		|| parser.testIdentifierAndSkip("when"))
 	{
 		parser.seek(expressionIdentifierPosition);
-		const auto expressionIdentifier = parser.parseIdentifier(isIdentifier);
+		const auto expressionIdentifier = parser.parseIdentifier();
 
 		parser.seek(position);
 		return expressions::Unsupported::parse(context);
@@ -168,37 +166,39 @@ ExpressionPointer parseEffectBodyExpression(Context &context, ExpressionContext
 
 	const auto expressionIdentifierPosition = parser.position();
 
-	if (parser.probeIdentifier("=", isIdentifier)
-		|| parser.probeIdentifier("assign", isIdentifier)
-		|| parser.probeIdentifier("scale-up", isIdentifier)
-		|| parser.probeIdentifier("scale-down", isIdentifier)
-		|| parser.probeIdentifier("increase", isIdentifier)
-		|| parser.probeIdentifier("decrease", isIdentifier))
+	if (parser.testIdentifierAndSkip("=")
+		|| parser.testIdentifierAndSkip("assign")
+		|| parser.testIdentifierAndSkip("scale-up")
+		|| parser.testIdentifierAndSkip("scale-down")
+		|| parser.testIdentifierAndSkip("increase")
+		|| parser.testIdentifierAndSkip("decrease"))
 	{
 		parser.seek(expressionIdentifierPosition);
-		const auto expressionIdentifier = parser.parseIdentifier(isIdentifier);
+		const auto expressionIdentifier = parser.parseIdentifier();
 
 		parser.seek(position);
 		return expressions::Unsupported::parse(context);
 	}
 
 	parser.seek(expressionIdentifierPosition);
-	const auto expressionIdentifier = parser.parseIdentifier(isIdentifier);
+	const auto expressionIdentifier = parser.parseIdentifier();
 
 	parser.seek(position);
-	throw utils::ParserException(context.parser, "expression type “" + expressionIdentifier + "” unknown or not allowed in this context");
+	throw utils::ParserException(parser.coordinate(), "expression type “" + expressionIdentifier + "” unknown or not allowed in this context");
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 ExpressionPointer parsePredicate(Context &context, ExpressionContext &expressionContext)
 {
+	auto &parser = context.parser;
+
 	ExpressionPointer expression;
 
 	if ((expression = expressions::Predicate::parse(context, expressionContext)))
 		return expression;
 
-	throw utils::ParserException(context.parser, "expected predicate");
+	throw utils::ParserException(parser.coordinate(), "expected predicate");
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -229,15 +229,15 @@ ExpressionPointer parseAtomicFormula(Context &context, ExpressionContext &expres
 
 	const auto position = parser.position();
 
-	if (!parser.probe<std::string>("("))
+	if (!parser.testAndSkip<std::string>("("))
 		return nullptr;
 
 	const auto expressionIdentifierPosition = parser.position();
 
-	if (parser.probeIdentifier("=", isIdentifier))
+	if (parser.testIdentifierAndSkip("="))
 	{
 		parser.seek(expressionIdentifierPosition);
-		const auto expressionIdentifier = parser.parseIdentifier(isIdentifier);
+		const auto expressionIdentifier = parser.parseIdentifier();
 
 		parser.seek(position);
 		return expressions::Unsupported::parse(context);

src/plasp/pddl/InitialState.cpp

@@ -2,7 +2,6 @@
 
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/ExpressionContext.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/IO.h>
 #include <plasp/pddl/Problem.h>
 #include <plasp/pddl/expressions/At.h>
@@ -46,20 +45,20 @@ std::unique_ptr<InitialState> InitialState::parseDeclaration(Context &context,
 
 			const auto expressionIdentifierPosition = parser.position();
 
-			if (parser.probeIdentifier("=", isIdentifier))
+			if (parser.testIdentifierAndSkip("="))
 			{
 				parser.seek(expressionIdentifierPosition);
-				const auto expressionIdentifier = parser.parseIdentifier(isIdentifier);
+				const auto expressionIdentifier = parser.parseIdentifier();
 
 				parser.seek(position);
 				return expressions::Unsupported::parse(context);
 			}
 
 			parser.seek(expressionIdentifierPosition);
-			const auto expressionIdentifier = parser.parseIdentifier(isIdentifier);
+			const auto expressionIdentifier = parser.parseIdentifier();
 
 			parser.seek(position);
-			throw utils::ParserException(parser, "expression type “" + expressionIdentifier + "” unknown or not allowed in this context");
+			throw utils::ParserException(parser.coordinate(), "expression type “" + expressionIdentifier + "” unknown or not allowed in this context");
 		};
 
 	parser.skipWhiteSpace();

src/plasp/pddl/Problem.cpp

@@ -4,10 +4,8 @@
 
 #include <plasp/pddl/Domain.h>
 #include <plasp/pddl/ExpressionContext.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/IO.h>
 #include <plasp/pddl/expressions/Constant.h>
-#include <plasp/utils/IO.h>
 #include <plasp/utils/ParserException.h>
 
 namespace plasp
@@ -43,7 +41,7 @@ void Problem::findSections()
 	parser.expect<std::string>("(");
 	parser.expect<std::string>("problem");
 
-	m_name = parser.parseIdentifier(isIdentifier);
+	m_name = parser.parseIdentifier();
 
 	parser.expect<std::string>(")");
 
@@ -53,7 +51,7 @@ void Problem::findSections()
 		if (unique && sectionPosition != -1)
 		{
 			parser.seek(value);
-			throw utils::ParserException(parser, "only one “:" + sectionName + "” section allowed");
+			throw utils::ParserException(parser.coordinate(), "only one “:" + sectionName + "” section allowed");
 		}
 
 		sectionPosition = value;
@@ -71,34 +69,34 @@ void Problem::findSections()
 		const auto sectionIdentifierPosition = parser.position();
 
 		// TODO: check order of the sections
-		if (parser.probeIdentifier("domain", isIdentifier))
+		if (parser.testIdentifierAndSkip("domain"))
 			setSectionPosition("domain", m_domainPosition, position, true);
-		else if (parser.probeIdentifier("requirements", isIdentifier))
+		else if (parser.testIdentifierAndSkip("requirements"))
 			setSectionPosition("requirements", m_requirementsPosition, position, true);
-		else if (parser.probeIdentifier("objects", isIdentifier))
+		else if (parser.testIdentifierAndSkip("objects"))
 			setSectionPosition("objects", m_objectsPosition, position, true);
-		else if (parser.probeIdentifier("init", isIdentifier))
+		else if (parser.testIdentifierAndSkip("init"))
 			setSectionPosition("init", m_initialStatePosition, position, true);
-		else if (parser.probeIdentifier("goal", isIdentifier))
+		else if (parser.testIdentifierAndSkip("goal"))
 			setSectionPosition("goal", m_goalPosition, position, true);
-		else if (parser.probeIdentifier("constraints", isIdentifier)
-			|| parser.probeIdentifier("metric", isIdentifier)
-			|| parser.probeIdentifier("length", isIdentifier))
+		else if (parser.testIdentifierAndSkip("constraints")
+			|| parser.testIdentifierAndSkip("metric")
+			|| parser.testIdentifierAndSkip("length"))
 		{
 			parser.seek(sectionIdentifierPosition);
 
-			const auto sectionIdentifier = parser.parseIdentifier(isIdentifier);
+			const auto sectionIdentifier = parser.parseIdentifier();
 
-			m_context.logger.logWarning(parser, "section type “" + sectionIdentifier + "” currently unsupported");
+			m_context.logger.logWarning(parser.coordinate(), "section type “" + sectionIdentifier + "” currently unsupported");
 
 			parser.seek(sectionIdentifierPosition);
 		}
 		else
 		{
-			const auto sectionIdentifier = parser.parseIdentifier(isIdentifier);
+			const auto sectionIdentifier = parser.parseIdentifier();
 
 			parser.seek(position);
-			throw utils::ParserException(m_context.parser, "unknown problem section “" + sectionIdentifier + "”");
+			throw utils::ParserException(parser.coordinate(), "unknown problem section “" + sectionIdentifier + "”");
 		}
 
 		// Skip section for now and parse it later
@@ -201,10 +199,10 @@ void Problem::parseDomainSection()
 
 	parser.skipWhiteSpace();
 
-	const auto domainName = parser.parseIdentifier(isIdentifier);
+	const auto domainName = parser.parseIdentifier();
 
 	if (m_domain.name() != domainName)
-		throw utils::ParserException(parser, "domains do not match (“" + m_domain.name() + "” and “" + domainName + "”)");
+		throw utils::ParserException(parser.coordinate(), "domains do not match (“" + m_domain.name() + "” and “" + domainName + "”)");
 
 	parser.expect<std::string>(")");
 }
@@ -256,12 +254,14 @@ bool Problem::hasRequirement(Requirement::Type requirementType) const
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-void Problem::checkRequirement(Requirement::Type requirementType) const
+void Problem::checkRequirement(Requirement::Type requirementType)
 {
 	if (hasRequirement(requirementType))
 		return;
 
-	throw ConsistencyException("requirement “" + Requirement(requirementType).toPDDL() + "” used but never declared");
+	m_context.logger.logWarning(m_context.parser.coordinate(), "requirement “" + Requirement(requirementType).toPDDL() + "” used but never declared");
+
+	m_requirements.push_back(requirementType);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////

src/plasp/pddl/Requirement.cpp

@@ -4,8 +4,6 @@
 #include <boost/assign.hpp>
 #include <boost/bimap.hpp>
 
-#include <plasp/pddl/Identifier.h>
-#include <plasp/utils/IO.h>
 #include <plasp/utils/ParserException.h>
 
 namespace plasp
@@ -84,17 +82,19 @@ Requirement::Requirement(Requirement::Type type)
 
 Requirement Requirement::parse(Context &context)
 {
-	const auto requirementName = context.parser.parseIdentifier(isIdentifier);
+	auto &parser = context.parser;
+
+	const auto requirementName = parser.parseIdentifier();
 
 	const auto match = requirementTypesToPDDL.right.find(requirementName);
 
 	if (match == requirementTypesToPDDL.right.end())
-		throw utils::ParserException(context.parser, "unknown PDDL requirement “" + requirementName + "”");
+		throw utils::ParserException(parser.coordinate(), "unknown PDDL requirement “" + requirementName + "”");
 
 	const auto requirementType = match->second;
 
 	if (requirementType == Requirement::Type::GoalUtilities)
-		context.logger.logWarning(context.parser, "requirement “goal-utilities” is not part of the PDDL 3.1 specification");
+		context.logger.logWarning(parser.coordinate(), "requirement “goal-utilities” is not part of the PDDL 3.1 specification");
 
 	return Requirement(match->second);
 }

src/plasp/pddl/TranslatorASP.cpp

@@ -6,7 +6,6 @@
 #include <plasp/pddl/expressions/Not.h>
 #include <plasp/pddl/expressions/Predicate.h>
 #include <plasp/utils/Formatting.h>
-#include <plasp/utils/IO.h>
 #include <plasp/utils/TranslatorException.h>
 
 namespace plasp
@@ -20,10 +19,11 @@ namespace pddl
 //
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-TranslatorASP::TranslatorASP(const Description &description, utils::LogStream &outputStream)
+TranslatorASP::TranslatorASP(Description &description, utils::LogStream &outputStream)
 :	m_description(description),
 	m_outputStream(outputStream)
 {
+	m_description.normalizeParameterNames();
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -85,62 +85,99 @@ void TranslatorASP::translateTypes() const
 
 	if (types.empty())
 	{
-		m_outputStream << utils::Keyword("type") << "(object)." << std::endl;
+		m_outputStream
+			<< utils::RuleName("type") << "("
+			<< utils::Keyword("type") << "(" << utils::String("object") << "))." << std::endl;
+
 		return;
 	}
 
 	std::for_each(types.cbegin(), types.cend(),
 		[&](const auto &type)
 		{
-			const auto typeName = utils::escapeASP(type->name());
-
-			m_outputStream << utils::Keyword("type") << "(" << typeName << ")." << std::endl;
+			m_outputStream
+				<< utils::RuleName("type") << "("
+				<< utils::Keyword("type") << "("
+				<< utils::String(type->name())
+				<< "))." << std::endl;
 
 			const auto &parentTypes = type->parentTypes();
 
 			std::for_each(parentTypes.cbegin(), parentTypes.cend(),
 				[&](const auto &parentType)
 				{
-					const auto parentTypeName = utils::escapeASP(parentType->name());
+					m_outputStream
+						<< utils::RuleName("inherits") << "(" << utils::Keyword("type")
+						<< "(" << utils::String(type->name()) << "), " << utils::Keyword("type")
+						<< "(" << utils::String(parentType->name()) << "))." << std::endl;
+				});
+		});
 
 	m_outputStream
-						<< utils::Keyword("inherits") << "(" << utils::Keyword("type")
-						<< "(" << typeName << "), " << utils::Keyword("type")
-						<< "(" << parentTypeName << "))." << std::endl
-
-						<< utils::Keyword("hasType") << "(" << utils::Variable("X") << ", "
-						<< utils::Keyword("type") << "(" << parentTypeName << ")) :- "
-						<< utils::Keyword("hasType") << "(" << utils::Variable("X") << ", "
-						<< utils::Keyword("type") << "(" << typeName << "))." << std::endl;
-				});
-		});
+		<< std::endl
+		<< utils::RuleName("has") << "("
+		<< utils::Variable("X") << ", "
+		<< utils::Keyword("type") << "(" << utils::Variable("T2") << ")) :- "
+		<< utils::RuleName("has") << "("
+		<< utils::Variable("X") << ", "
+		<< utils::Keyword("type") << "(" << utils::Variable("T1") << ")), "
+		<< utils::RuleName("inherits") << "("
+		<< utils::Keyword("type") << "(" << utils::Variable("T1") << "), "
+		<< utils::Keyword("type") << "(" << utils::Variable("T2") << "))."
+		<< std::endl;
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 void TranslatorASP::translatePredicates() const
 {
-	m_outputStream << utils::Heading2("predicates");
+	m_outputStream << utils::Heading2("variables");
 
 	const auto &predicates = m_description.domain().predicates();
 
+	const auto printPredicateName =
+		[&](const auto &predicate)
+		{
+			if (predicate->arguments().empty())
+			{
+				m_outputStream << utils::String(predicate->name());
+
+				return;
+			}
+
+			m_outputStream << "(" << utils::String(predicate->name());
+			this->translateVariablesHead(predicate->arguments());
+			m_outputStream << ")";
+		};
+
 	std::for_each(predicates.cbegin(), predicates.cend(),
 		[&](const auto &predicate)
 		{
-			m_outputStream << std::endl;
+			m_outputStream
+				<< std::endl
+				<< utils::RuleName("variable") << "("
+				<< utils::Keyword("variable") << "(";
 
-			m_outputStream << utils::Keyword("predicate") << "(" << utils::escapeASP(predicate->name());
+			printPredicateName(predicate);
 
-			this->translateVariablesHead(predicate->arguments());
-
-			m_outputStream << ")";
+			m_outputStream << "))";
 
 			this->translateVariablesBody(predicate->arguments());
 
 			m_outputStream << ".";
 		});
 
-	m_outputStream << std::endl;
+	m_outputStream
+		<< std::endl << std::endl
+		<< utils::RuleName("boolean") << "(" << utils::Boolean("true") << ")." << std::endl
+		<< utils::RuleName("boolean") << "(" << utils::Boolean("false") << ")." << std::endl
+		<< std::endl
+		<< utils::RuleName("contains") << "("
+		<< utils::Keyword("variable") << "(" << utils::Variable("X") << "), "
+		<< utils::Keyword("value") << "(" << utils::Variable("X") << ", " << utils::Variable("B") << ")) :- "
+		<< utils::RuleName("variable") << "(" << utils::Keyword("variable") << "(" << utils::Variable("X") << ")), "
+		<< utils::RuleName("boolean") << "(" << utils::Variable("B") << ")."
+		<< std::endl;
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -154,38 +191,52 @@ void TranslatorASP::translateActions() const
 	const auto printActionName =
 		[&](const auto &action)
 		{
-			m_outputStream << utils::Keyword("action") << "(" << utils::escapeASP(action.name());
+			m_outputStream << utils::Keyword("action") << "(";
 
+			if (action.parameters().empty())
+			{
+				m_outputStream << utils::String(action.name()) << ")";
+
+				return;
+			}
+
+			m_outputStream << "(" << utils::String(action.name());
 			this->translateVariablesHead(action.parameters());
-
-			m_outputStream << ")";
+			m_outputStream << "))";
 		};
 
 	std::for_each(actions.cbegin(), actions.cend(),
 		[&](const auto &action)
 		{
+			// TODO: rename
 			const auto translateLiteral =
-				[&](const auto &ruleHead, const auto &literal)
+				[&](const auto &ruleHead, const auto &literal, bool enumerateEffects = false)
 				{
-					m_outputStream << std::endl << utils::Keyword(ruleHead) << "(";
+					m_outputStream << std::endl << utils::RuleName(ruleHead) << "(";
 
 					printActionName(*action);
 
+					// TODO: implement conditional effects
+					if (enumerateEffects)
+						m_outputStream << ", " << utils::Keyword("effect") << "(" << utils::Reserved("unconditional") << ")";
+
 					m_outputStream << ", ";
 
 					this->translateLiteral(literal);
 
-					m_outputStream << ") :- ";
+					m_outputStream << ") :- " << utils::RuleName("action") << "(";
 
 					printActionName(*action);
 
-					m_outputStream << ".";
+					m_outputStream << ").";
 				};
 
 			m_outputStream << std::endl;
 
 			// Name
+			m_outputStream << utils::RuleName("action") << "(";
 			printActionName(*action);
+			m_outputStream << ")";
 
 			this->translateVariablesBody(action->parameters());
 
@@ -225,7 +276,7 @@ void TranslatorASP::translateActions() const
 				if (effect.expressionType() == Expression::Type::Predicate
 					|| effect.expressionType() == Expression::Type::Not)
 				{
-					translateLiteral("postcondition", effect);
+					translateLiteral("postcondition", effect, true);
 				}
 				// Assuming a conjunction
 				else
@@ -238,7 +289,7 @@ void TranslatorASP::translateActions() const
 					std::for_each(andExpression.arguments().cbegin(), andExpression.arguments().cend(),
 						[&](const auto *argument)
 						{
-							translateLiteral("postcondition", *argument);
+							translateLiteral("postcondition", *argument, true);
 						});
 				}
 			}
@@ -256,24 +307,25 @@ void TranslatorASP::translateConstants(const std::string &heading, const express
 	std::for_each(constants.cbegin(), constants.cend(),
 		[&](const auto &constant)
 		{
-			const auto constantName = utils::escapeASP(constant->name());
-
-			m_outputStream << std::endl << utils::Keyword("constant")
-				<< "(" << constantName << ")." << std::endl;
+			m_outputStream << std::endl
+				<< utils::RuleName("constant") << "("
+				<< utils::Keyword("constant") << "("
+				<< utils::String(constant->name())
+				<< "))." << std::endl;
 
 			const auto *type = constant->type();
 
 			if (type != nullptr)
 			{
-				m_outputStream << utils::Keyword("hasType") << "("
-					<< utils::Keyword("constant") << "(" << constantName << "), "
-					<< utils::Keyword("type") << "(" << utils::escapeASP(type->name()) << "))." << std::endl;
+				m_outputStream << utils::RuleName("has") << "("
+					<< utils::Keyword("constant") << "(" << utils::String(constant->name()) << "), "
+					<< utils::Keyword("type") << "(" << utils::String(type->name()) << "))." << std::endl;
 			}
 			else
 			{
-				m_outputStream << utils::Keyword("hasType") << "("
-					<< utils::Keyword("constant") << "(" << constantName << "), "
-					<< utils::Keyword("type") << "(object))." << std::endl;
+				m_outputStream << utils::RuleName("has") << "("
+					<< utils::Keyword("constant") << "(" << utils::String(constant->name()) << "), "
+					<< utils::Keyword("type") << "(" << utils::String("object") << "))." << std::endl;
 			}
 		});
 }
@@ -285,19 +337,12 @@ void TranslatorASP::translateVariablesHead(const expressions::Variables &variabl
 	if (variables.empty())
 		return;
 
-	m_outputStream << "(";
-
 	for (auto i = variables.cbegin(); i != variables.cend(); i++)
 	{
-		if (i != variables.cbegin())
-			m_outputStream << ", ";
-
 		const auto &variable = **i;
 
-		m_outputStream << utils::Variable(utils::escapeASPVariable(variable.name()));
+		m_outputStream << ", " << utils::Variable(variable.name());
 	}
-
-	m_outputStream << ")";
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -323,15 +368,15 @@ void TranslatorASP::translateVariablesBody(const expressions::Variables &variabl
 
 			const auto &type = *dynamic_cast<const expressions::PrimitiveType *>(variable.type());
 
-			m_outputStream << utils::Keyword("hasType") << "("
-				<< utils::Variable(utils::escapeASPVariable(variable.name())) << ", "
-				<< utils::Keyword("type") << "(" << utils::escapeASP(type.name()) << "))";
+			m_outputStream << utils::RuleName("has") << "("
+				<< utils::Variable(variable.name()) << ", "
+				<< utils::Keyword("type") << "(" << utils::String(type.name()) << "))";
 		}
 		else
 		{
-			m_outputStream << utils::Keyword("hasType") << "("
-				<< utils::Variable(utils::escapeASPVariable(variable.name())) << ", "
-				<< utils::Keyword("type") << "(object))";
+			m_outputStream << utils::RuleName("has") << "("
+				<< utils::Variable(variable.name()) << ", "
+				<< utils::Keyword("type") << "(" << utils::String("object") << "))";
 		}
 	}
 }
@@ -343,17 +388,29 @@ void TranslatorASP::translateLiteral(const Expression &literal) const
 	// Translate single predicate
 	if (literal.expressionType() == Expression::Type::Predicate)
 	{
-		this->translatePredicate(dynamic_cast<const expressions::Predicate &>(literal));
-		m_outputStream << ", " << utils::Keyword("true");
+		const auto &predicate = dynamic_cast<const expressions::Predicate &>(literal);
+
+		m_outputStream << utils::Keyword("variable") << "(";
+		this->translatePredicate(predicate);
+		m_outputStream << "), " << utils::Keyword("value") << "(";
+		this->translatePredicate(predicate);
+		m_outputStream << ", " << utils::Boolean("true") << ")";
 	}
 	// Assuming that "not" expression may only contain a predicate
 	else if (literal.expressionType() == Expression::Type::Not)
 	{
 		const auto &notExpression = dynamic_cast<const expressions::Not &>(literal);
+
+		if (notExpression.argument()->expressionType() != Expression::Type::Predicate)
+			throw utils::TranslatorException("only negations of primitive predicates supported as literals currently");
+
 		const auto &predicate = dynamic_cast<const expressions::Predicate &>(*notExpression.argument());
 
+		m_outputStream << utils::Keyword("variable") << "(";
 		this->translatePredicate(predicate);
-		m_outputStream << ", " << utils::Keyword("false");
+		m_outputStream << "), " << utils::Keyword("value") << "(";
+		this->translatePredicate(predicate);
+		m_outputStream << ", " << utils::Boolean("false") << ")";
 	}
 	else
 		throw utils::TranslatorException("only primitive predicates and their negations supported as literals currently");
@@ -363,40 +420,38 @@ void TranslatorASP::translateLiteral(const Expression &literal) const
 
 void TranslatorASP::translatePredicate(const expressions::Predicate &predicate) const
 {
-	m_outputStream << utils::Keyword("predicate") << "(" << utils::escapeASP(predicate.name());
-
 	const auto &arguments = predicate.arguments();
 
 	if (arguments.empty())
 	{
-		m_outputStream << ")";
+		m_outputStream << utils::String(predicate.name());
+
 		return;
 	}
 
-	m_outputStream << "(";
+	m_outputStream << "(" << utils::String(predicate.name());
 
 	for (auto i = arguments.cbegin(); i != arguments.cend(); i++)
 	{
-		if (i != arguments.cbegin())
 		m_outputStream << ", ";
 
 		if ((*i)->expressionType() == Expression::Type::Constant)
 		{
 			const auto &constant = dynamic_cast<const expressions::Constant &>(**i);
 
-			m_outputStream << utils::Keyword("constant") << "(" << utils::escapeASP(constant.name()) << ")";
+			m_outputStream << utils::Keyword("constant") << "(" << utils::String(constant.name()) << ")";
 		}
 		else if ((*i)->expressionType() == Expression::Type::Variable)
 		{
 			const auto &variable = dynamic_cast<const expressions::Variable &>(**i);
 
-			m_outputStream << utils::Variable(utils::escapeASPVariable(variable.name()));
+			m_outputStream << utils::Variable(variable.name());
 		}
 		else
 			throw utils::TranslatorException("only variables and constants supported in predicates currently");
 	}
 
-	m_outputStream << "))";
+	m_outputStream << ")";
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -438,11 +493,19 @@ void TranslatorASP::translateInitialState() const
 	std::for_each(initialStateFacts.cbegin(), initialStateFacts.cend(),
 		[&](const auto &fact)
 		{
-			m_outputStream << std::endl << utils::Keyword("initialState") << "(";
+			m_outputStream << std::endl << utils::RuleName("initialState") << "(";
 
 			// Translate single predicate
 			if (fact->expressionType() == Expression::Type::Predicate)
-				this->translatePredicate(dynamic_cast<const expressions::Predicate &>(*fact));
+			{
+				const auto &predicate = dynamic_cast<const expressions::Predicate &>(*fact);
+
+				m_outputStream << utils::Keyword("variable") << "(";
+				this->translatePredicate(predicate);
+				m_outputStream << "), " << utils::Keyword("value") << "(";
+				this->translatePredicate(predicate);
+				m_outputStream << ", " << utils::Boolean("true") << ")";
+			}
 			// Assuming that "not" expression may only contain a predicate
 			else if (fact->expressionType() == Expression::Type::Not)
 			{
@@ -457,7 +520,17 @@ void TranslatorASP::translateInitialState() const
 			m_outputStream << ").";
 		});
 
-	m_outputStream << std::endl;
+	m_outputStream
+		<< std::endl << std::endl
+		<< utils::RuleName("initialState") << "("
+		<< utils::Keyword("variable") << "(" << utils::Variable("X") << "), "
+		<< utils::Keyword("value") << "(" << utils::Variable("X") << ", " << utils::Boolean("false") << ")) :- "
+		<< utils::RuleName("variable") << "(" << utils::Keyword("variable") << "(" << utils::Variable("X") << ")), "
+		<< utils::Keyword("not") << " "
+		<< utils::RuleName("initialState") << "("
+		<< utils::Keyword("variable") << "(" << utils::Variable("X") << "), "
+		<< utils::Keyword("value") << "(" << utils::Variable("X") << ", " << utils::Boolean("true") << "))."
+		<< std::endl;
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -473,7 +546,7 @@ void TranslatorASP::translateGoal() const
 	if (goal.expressionType() == Expression::Type::Predicate
 		|| goal.expressionType() == Expression::Type::Not)
 	{
-		m_outputStream << std::endl << utils::Keyword("goal") << "(";
+		m_outputStream << std::endl << utils::RuleName("goal") << "(";
 
 		translateLiteral(goal);
 
@@ -486,7 +559,7 @@ void TranslatorASP::translateGoal() const
 		std::for_each(andExpression.arguments().cbegin(), andExpression.arguments().cend(),
 			[&](const auto *argument)
 			{
-				m_outputStream << std::endl << utils::Keyword("goal") << "(";
+				m_outputStream << std::endl << utils::RuleName("goal") << "(";
 
 				this->translateLiteral(*argument);
 

src/plasp/pddl/expressions/Constant.cpp

@@ -37,7 +37,7 @@ ConstantPointer Constant::parseDeclaration(Context &context)
 
 	auto constant = std::make_unique<Constant>(Constant());
 
-	constant->m_name = context.parser.parseIdentifier(isIdentifier);
+	constant->m_name = context.parser.parseIdentifier();
 
 	BOOST_ASSERT(constant->m_name != "-");
 
@@ -71,7 +71,7 @@ void Constant::parseTypedDeclaration(Context &context, Domain &domain, Constants
 	context.parser.skipWhiteSpace();
 
 	// Check for typing information
-	if (!context.parser.probe('-'))
+	if (!context.parser.testAndSkip<char>('-'))
 		return;
 
 	// If existing, parse and store parent type
@@ -113,7 +113,7 @@ void Constant::parseTypedDeclarations(Context &context, Domain &domain)
 		domain.checkRequirement(Requirement::Type::Typing);
 	// If no types are given, check that typing is not a requirement
 	else if (domain.hasRequirement(Requirement::Type::Typing))
-		throw utils::ParserException(parser, "constant has undeclared type");
+		throw utils::ParserException(parser.coordinate(), "constant has undeclared type");
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -140,32 +140,36 @@ void Constant::parseTypedDeclarations(Context &context, Problem &problem)
 		problem.checkRequirement(Requirement::Type::Typing);
 	// If no types are given, check that typing is not a requirement
 	else if (problem.hasRequirement(Requirement::Type::Typing))
-		throw utils::ParserException(context.parser, "constant has undeclared type");
+		throw utils::ParserException(parser.coordinate(), "constant has undeclared type");
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 Constant *Constant::parseAndFind(Context &context, const Domain &domain)
 {
-	context.parser.skipWhiteSpace();
+	auto &parser = context.parser;
 
-	const auto constantName = context.parser.parseIdentifier(isIdentifier);
+	parser.skipWhiteSpace();
+
+	const auto constantName = parser.parseIdentifier();
 
 	auto *constant = parseAndFind(constantName, domain.constants());
 
 	if (constant != nullptr)
 		return constant;
 
-	throw utils::ParserException(context.parser, "constant “" + constantName + "” used but never declared");
+	throw utils::ParserException(parser.coordinate(), "constant “" + constantName + "” used but never declared");
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 Constant *Constant::parseAndFind(Context &context, const Problem &problem)
 {
-	context.parser.skipWhiteSpace();
+	auto &parser = context.parser;
 
-	const auto constantName = context.parser.parseIdentifier(isIdentifier);
+	parser.skipWhiteSpace();
+
+	const auto constantName = parser.parseIdentifier();
 
 	auto *constant = parseAndFind(constantName, problem.domain().constants());
 
@@ -177,7 +181,7 @@ Constant *Constant::parseAndFind(Context &context, const Problem &problem)
 	if (constant)
 		return constant;
 
-	throw utils::ParserException(context.parser, "constant “" + constantName + "” used but never declared");
+	throw utils::ParserException(parser.coordinate(), "constant “" + constantName + "” used but never declared");
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////

src/plasp/pddl/expressions/Imply.cpp

@@ -13,6 +13,7 @@ namespace expressions
 //
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+// TODO: make static character string literal
 const std::string Imply::Identifier = "imply";
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////

src/plasp/pddl/expressions/Predicate.cpp

@@ -3,7 +3,6 @@
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Domain.h>
 #include <plasp/pddl/ExpressionContext.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/Problem.h>
 #include <plasp/pddl/expressions/Constant.h>
 #include <plasp/pddl/expressions/Variable.h>
@@ -34,13 +33,13 @@ PredicatePointer Predicate::parse(Context &context, ExpressionContext &expressio
 
 	const auto position = parser.position();
 
-	if (!parser.probe<std::string>("("))
+	if (!parser.testAndSkip<std::string>("("))
 	{
 		parser.seek(position);
 		return nullptr;
 	}
 
-	const auto predicateName = parser.parseIdentifier(isIdentifier);
+	const auto predicateName = parser.parseIdentifier();
 	const auto &predicates = expressionContext.domain.predicates();
 
 	const auto matchingPredicate = std::find_if(predicates.cbegin(), predicates.cend(),
@@ -97,13 +96,13 @@ PredicatePointer Predicate::parse(Context &context, const Problem &problem)
 
 	const auto position = parser.position();
 
-	if (!parser.probe<std::string>("("))
+	if (!parser.testAndSkip<std::string>("("))
 	{
 		parser.seek(position);
 		return nullptr;
 	}
 
-	const auto predicateName = parser.parseIdentifier(isIdentifier);
+	const auto predicateName = parser.parseIdentifier();
 	const auto &predicates = problem.domain().predicates();
 
 	const auto matchingPredicate = std::find_if(predicates.cbegin(), predicates.cend(),
@@ -122,12 +121,12 @@ PredicatePointer Predicate::parse(Context &context, const Problem &problem)
 
 	predicate->m_name = predicateName;
 
-	context.parser.skipWhiteSpace();
+	parser.skipWhiteSpace();
 
-	while (context.parser.currentCharacter() != ')')
+	while (parser.currentCharacter() != ')')
 	{
-		if (context.parser.currentCharacter() == '?')
-			throw utils::ParserException(context.parser, "variables not allowed in this context");
+		if (parser.currentCharacter() == '?')
+			throw utils::ParserException(parser.coordinate(), "variables not allowed in this context");
 
 		// Parse objects and constants
 		const auto *constant = Constant::parseAndFind(context, problem);

src/plasp/pddl/expressions/PredicateDeclaration.cpp

@@ -3,7 +3,6 @@
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Domain.h>
 #include <plasp/pddl/ExpressionContext.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/expressions/Constant.h>
 #include <plasp/pddl/expressions/Variable.h>
 
@@ -33,7 +32,7 @@ void PredicateDeclaration::parse(Context &context, Domain &domain)
 
 	auto predicate = std::make_unique<PredicateDeclaration>(PredicateDeclaration());
 
-	predicate->m_name = context.parser.parseIdentifier(isIdentifier);
+	predicate->m_name = context.parser.parseIdentifier();
 
 	// Flag predicate as correctly declared in the types section
 	predicate->setDeclared();
@@ -80,6 +79,14 @@ const Variables &PredicateDeclaration::arguments() const
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+void PredicateDeclaration::normalizeParameterNames()
+{
+	for (size_t i = 0; i < m_parameters.size(); i++)
+		m_parameters[i]->setName("X" + std::to_string(i));
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 }
 }
 }

src/plasp/pddl/expressions/PrimitiveType.cpp

@@ -43,7 +43,7 @@ void PrimitiveType::parseDeclaration(Context &context, Domain &domain)
 
 	context.parser.skipWhiteSpace();
 
-	const auto typeName = context.parser.parseIdentifier(isIdentifier);
+	const auto typeName = context.parser.parseIdentifier();
 
 	const auto match = std::find_if(types.cbegin(), types.cend(),
 		[&](const auto &primitiveType)
@@ -76,7 +76,7 @@ void PrimitiveType::parseTypedDeclaration(Context &context, Domain &domain)
 	context.parser.skipWhiteSpace();
 
 	// Check for type inheritance
-	if (!context.parser.probe('-'))
+	if (!context.parser.testAndSkip<char>('-'))
 		return;
 
 	domain.checkRequirement(Requirement::Type::Typing);
@@ -102,14 +102,16 @@ void PrimitiveType::parseTypedDeclaration(Context &context, Domain &domain)
 
 PrimitiveType *PrimitiveType::parseAndFind(Context &context, Domain &domain)
 {
+	auto &parser = context.parser;
+
 	auto &types = domain.types();
 
-	context.parser.skipWhiteSpace();
+	parser.skipWhiteSpace();
 
-	const auto typeName = context.parser.parseIdentifier(isIdentifier);
+	const auto typeName = parser.parseIdentifier();
 
 	if (typeName.empty())
-		throw utils::ParserException(context.parser, "no type supplied");
+		throw utils::ParserException(parser.coordinate(), "no type supplied");
 
 	const auto match = std::find_if(types.cbegin(), types.cend(),
 		[&](const auto &primitiveType)
@@ -122,11 +124,11 @@ PrimitiveType *PrimitiveType::parseAndFind(Context &context, Domain &domain)
 		// Only "object" is allowed as an implicit type
 		if (typeName == "object" || typeName == "objects")
 		{
-			context.logger.logWarning(context.parser, "primitive type “" + typeName + "” should be declared");
+			context.logger.logWarning(parser.coordinate(), "primitive type “" + typeName + "” should be declared");
 			types.emplace_back(std::make_unique<expressions::PrimitiveType>(typeName));
 		}
 		else
-			throw utils::ParserException(context.parser, "type “" + typeName + "” used but never declared");
+			throw utils::ParserException(parser.coordinate(), "type “" + typeName + "” used but never declared");
 
 		return types.back().get();
 	}

src/plasp/pddl/expressions/Unsupported.cpp

@@ -1,6 +1,5 @@
 #include <plasp/pddl/expressions/Unsupported.h>
 
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/IO.h>
 
 namespace plasp
@@ -24,9 +23,9 @@ UnsupportedPointer Unsupported::parse(Context &context)
 
 	parser.expect<std::string>("(");
 
-	expression->m_type = parser.parseIdentifier(isIdentifier);
+	expression->m_type = parser.parseIdentifier();
 
-	context.logger.logWarning(context.parser, "expression type “" + expression->m_type + "” currently unsupported in this context");
+	context.logger.logWarning(parser.coordinate(), "expression type “" + expression->m_type + "” currently unsupported in this context");
 
 	skipSection(parser);
 

src/plasp/pddl/expressions/Variable.cpp

@@ -7,7 +7,6 @@
 #include <plasp/pddl/Context.h>
 #include <plasp/pddl/Domain.h>
 #include <plasp/pddl/ExpressionContext.h>
-#include <plasp/pddl/Identifier.h>
 #include <plasp/pddl/expressions/Either.h>
 #include <plasp/pddl/expressions/PrimitiveType.h>
 #include <plasp/pddl/expressions/Type.h>
@@ -36,13 +35,15 @@ Variable::Variable()
 
 void Variable::parseDeclaration(Context &context, Variables &parameters)
 {
-	context.parser.skipWhiteSpace();
+	auto &parser = context.parser;
 
-	context.parser.expect<std::string>("?");
+	parser.skipWhiteSpace();
+
+	parser.expect<std::string>("?");
 
 	auto variable = std::make_unique<Variable>(Variable());
 
-	variable->m_name = context.parser.parseIdentifier(isIdentifier);
+	variable->m_name = parser.parseIdentifier();
 
 	// Check if variable of that name already exists in the current scope
 	const auto match = std::find_if(parameters.cbegin(), parameters.cend(),
@@ -52,7 +53,7 @@ void Variable::parseDeclaration(Context &context, Variables &parameters)
 		});
 
 	if (match != parameters.cend())
-		throw utils::ParserException(context.parser, "variable “" + variable->m_name + "” already declared in this scope");
+		throw utils::ParserException(parser.coordinate(), "variable “" + variable->m_name + "” already declared in this scope");
 
 	// Flag variable for potentially upcoming type declaration
 	variable->setDirty();
@@ -75,7 +76,7 @@ void Variable::parseTypedDeclaration(Context &context, ExpressionContext &expres
 	parser.skipWhiteSpace();
 
 	// Check if the variable has a type declaration
-	if (!parser.probe('-'))
+	if (!parser.testAndSkip<char>('-'))
 		return;
 
 	const auto setType =
@@ -132,18 +133,20 @@ void Variable::parseTypedDeclarations(Context &context, ExpressionContext &expre
 		expressionContext.checkRequirement(Requirement::Type::Typing);
 	// If no types are given, check that typing is not a requirement
 	else if (expressionContext.hasRequirement(Requirement::Type::Typing))
-		throw utils::ParserException(parser, "variable has undeclared type");
+		throw utils::ParserException(parser.coordinate(), "variable has undeclared type");
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 const Variable *Variable::parseAndFind(Context &context, const ExpressionContext &expressionContext)
 {
-	context.parser.skipWhiteSpace();
+	auto &parser = context.parser;
 
-	context.parser.expect<std::string>("?");
+	parser.skipWhiteSpace();
 
-	const auto variableName = context.parser.parseIdentifier(isIdentifier);
+	parser.expect<std::string>("?");
+
+	const auto variableName = parser.parseIdentifier();
 
 	const auto &variables = expressionContext.parameters;
 
@@ -154,13 +157,20 @@ const Variable *Variable::parseAndFind(Context &context, const ExpressionContext
 		});
 
 	if (match == variables.cend())
-		throw utils::ParserException(context.parser, "parameter “" + variableName + "” used but never declared");
+		throw utils::ParserException(parser.coordinate(), "parameter “" + variableName + "” used but never declared");
 
 	return match->get();
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+void Variable::setName(std::string name)
+{
+	m_name = name;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 const std::string &Variable::name() const
 {
 	return m_name;

src/plasp/sas/AssignedVariable.cpp

@@ -31,7 +31,7 @@ AssignedVariable::AssignedVariable(const Variable &variable, const Value &value)
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-AssignedVariable AssignedVariable::fromSAS(utils::Parser &parser, const Variables &variables)
+AssignedVariable AssignedVariable::fromSAS(utils::Parser<> &parser, const Variables &variables)
 {
 	AssignedVariable assignedVariable;
 
@@ -43,7 +43,7 @@ AssignedVariable AssignedVariable::fromSAS(utils::Parser &parser, const Variable
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-AssignedVariable AssignedVariable::fromSAS(utils::Parser &parser, const Variable &variable)
+AssignedVariable AssignedVariable::fromSAS(utils::Parser<> &parser, const Variable &variable)
 {
 	AssignedVariable assignedVariable;
 

src/plasp/sas/AxiomRule.cpp

@@ -23,7 +23,7 @@ AxiomRule::AxiomRule(AxiomRule::Conditions conditions, AxiomRule::Condition post
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-AxiomRule AxiomRule::fromSAS(utils::Parser &parser, const Variables &variables)
+AxiomRule AxiomRule::fromSAS(utils::Parser<> &parser, const Variables &variables)
 {
 	parser.expect<std::string>("begin_rule");