foliage-rs/src/parse/formulas.rs

551 lines
11 KiB
Rust

use nom::
{
IResult,
branch::alt,
bytes::complete::tag,
character::complete::multispace0,
combinator::{cut, map, map_res},
multi::{many1, separated_list},
sequence::{delimited, pair, preceded, terminated, tuple},
};
use super::{Declarations, boolean, word_boundary};
pub fn predicate<'i>(i: &'i str, d: &Declarations) -> IResult<&'i str, crate::Predicate>
{
map
(
|i| crate::parse::terms::function_or_predicate(i, d),
|(name, arguments)|
{
let arguments = match arguments
{
Some(arguments) => arguments,
None => vec![],
};
let mut predicate_declarations = d.predicate_declarations.borrow_mut();
let declaration = match predicate_declarations.iter()
.find(|x| x.name == name && x.arity == arguments.len())
{
Some(declaration) => std::rc::Rc::clone(&declaration),
None =>
{
let declaration = crate::PredicateDeclaration
{
name: name.to_string(),
arity: arguments.len(),
};
let declaration = std::rc::Rc::new(declaration);
predicate_declarations.insert(std::rc::Rc::clone(&declaration));
declaration
},
};
crate::Predicate::new(declaration, arguments)
},
)(i)
}
fn not<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
map
(
preceded
(
terminated
(
tag("not"),
multispace0,
),
|i| formula_precedence_2(i, d),
),
|x| crate::Formula::not(Box::new(x)),
)(i)
}
fn and<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, Vec<Box<crate::Formula>>>
{
map_res
(
separated_list
(
delimited
(
multispace0,
terminated
(
tag("and"),
word_boundary,
),
multispace0,
),
|i| formula_precedence_2(i, d),
),
|arguments| -> Result<_, (_, _)>
{
if arguments.len() >= 2
{
Ok(arguments.into_iter().map(Box::new).collect())
}
else
{
Err(nom::error::make_error(i, nom::error::ErrorKind::Many1))
}
}
)(i)
}
fn or<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, Vec<Box<crate::Formula>>>
{
map_res
(
separated_list
(
delimited
(
multispace0,
terminated
(
tag("or"),
word_boundary,
),
multispace0,
),
|i| formula_precedence_3(i, d),
),
|arguments| -> Result<_, (_, _)>
{
if arguments.len() >= 2
{
Ok(arguments.into_iter().map(Box::new).collect())
}
else
{
Err(nom::error::make_error(i, nom::error::ErrorKind::Many1))
}
}
)(i)
}
fn implication_left_to_right<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
map
(
pair
(
many1
(
terminated
(
|i| formula_precedence_4(i, d),
delimited
(
multispace0,
tag("->"),
multispace0,
),
)
),
|i| formula_precedence_4(i, d),
),
|(arguments, last_argument)| arguments.into_iter().rev().fold(last_argument,
|accumulator, argument|
crate::Formula::implies(crate::ImplicationDirection::LeftToRight,
Box::new(accumulator), Box::new(argument)))
)(i)
}
fn implication_right_to_left<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
map
(
pair
(
|i| formula_precedence_4(i, d),
many1
(
preceded
(
delimited
(
multispace0,
tag("<-"),
multispace0,
),
|i| formula_precedence_4(i, d),
)
),
),
|(first_argument, arguments)| arguments.into_iter().fold(first_argument,
|accumulator, argument|
crate::Formula::implies(crate::ImplicationDirection::RightToLeft,
Box::new(accumulator), Box::new(argument)))
)(i)
}
fn if_and_only_if<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, Vec<Box<crate::Formula>>>
{
map_res
(
separated_list
(
delimited
(
multispace0,
tag("<->"),
multispace0,
),
|i| formula_precedence_5(i, d),
),
|arguments| -> Result<_, (_, _)>
{
if arguments.len() >= 2
{
Ok(arguments.into_iter().map(Box::new).collect())
}
else
{
Err(nom::error::make_error(i, nom::error::ErrorKind::Many1))
}
}
)(i)
}
fn quantified_expression<'a, 'b, T, N>(i: &'a str, d: &Declarations, keyword: &'b str,
new_functor: N)
-> IResult<&'a str, T>
where
N: Fn(std::rc::Rc<crate::VariableDeclarations>, Box<crate::Formula>) -> T
{
preceded
(
terminated
(
tag(keyword),
word_boundary,
),
cut
(
|i| -> IResult<&'a str, T>
{
let (i, variable_declarations) =
map
(
delimited
(
multispace0,
separated_list
(
delimited
(
multispace0,
tag(","),
multispace0,
),
map
(
crate::parse::terms::variable_declaration,
std::rc::Rc::new,
),
),
multispace0,
),
std::rc::Rc::new,
)(i)?;
if variable_declarations.is_empty()
{
return Err(nom::Err::Failure((i, nom::error::ErrorKind::Many1)));
}
d.variable_declaration_stack.borrow_mut().push(std::rc::Rc::clone(&variable_declarations));
let (i, argument) = formula_parenthesized(i, d)?;
// TODO: report logic errors more appropriately
d.variable_declaration_stack.borrow_mut().pop()
.map_err(|_| nom::Err::Failure((i, nom::error::ErrorKind::Verify)))?;
Ok((i, new_functor(variable_declarations, Box::new(argument))))
}
),
)(i)
}
fn compare<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Compare>
{
map
(
tuple
((
|i| crate::parse::term(i, d),
delimited
(
multispace0,
alt
((
map
(
tag(">"),
|_| crate::ComparisonOperator::Greater,
),
map
(
tag("<"),
|_| crate::ComparisonOperator::Less,
),
map
(
tag("<="),
|_| crate::ComparisonOperator::LessOrEqual,
),
map
(
tag(">="),
|_| crate::ComparisonOperator::GreaterOrEqual,
),
map
(
tag("!="),
|_| crate::ComparisonOperator::NotEqual,
),
map
(
tag("="),
|_| crate::ComparisonOperator::Equal,
),
)),
multispace0,
),
|i| crate::parse::term(i, d),
)),
|(left, operator, right)|
{
crate::Compare::new(operator, Box::new(left), Box::new(right))
}
)(i)
}
fn exists<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Exists>
{
quantified_expression::<crate::Exists, _>(i, d, "exists", crate::Exists::new)
}
fn for_all<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::ForAll>
{
quantified_expression::<crate::ForAll, _>(i, d, "forall", crate::ForAll::new)
}
fn formula_parenthesized<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
delimited
(
terminated
(
tag("("),
multispace0,
),
|i| formula(i, d),
preceded
(
multispace0,
tag(")"),
),
)(i)
}
fn formula_precedence_0<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
alt
((
map
(
boolean,
crate::Formula::Boolean,
),
map
(
|i| predicate(i, d),
crate::Formula::Predicate,
),
map
(
|i| compare(i, d),
crate::Formula::Compare,
),
|i| formula_parenthesized(i, d),
))(i)
}
fn formula_precedence_1<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
alt
((
map
(
|i| exists(i, d),
crate::Formula::Exists,
),
map
(
|i| for_all(i, d),
crate::Formula::ForAll,
),
|i| formula_precedence_0(i, d),
))(i)
}
fn formula_precedence_2<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
alt
((
|i| not(i, d),
|i| formula_precedence_1(i, d),
))(i)
}
fn formula_precedence_3<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
alt
((
map
(
|i| and(i, d),
crate::Formula::And,
),
|i| formula_precedence_2(i, d),
))(i)
}
fn formula_precedence_4<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
alt
((
map
(
|i| or(i, d),
crate::Formula::Or,
),
|i| formula_precedence_3(i, d),
))(i)
}
fn formula_precedence_5<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
alt
((
|i| implication_left_to_right(i, d),
|i| implication_right_to_left(i, d),
|i| formula_precedence_4(i, d),
))(i)
}
fn formula_precedence_6<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
alt
((
map
(
|i| if_and_only_if(i, d),
crate::Formula::IfAndOnlyIf,
),
|i| formula_precedence_5(i, d),
))(i)
}
pub fn formula<'a>(i: &'a str, d: &Declarations) -> IResult<&'a str, crate::Formula>
{
formula_precedence_6(i, d)
}
#[cfg(test)]
mod tests
{
use crate::parse::formulas::*;
use crate::{Formula, Term};
/*fn formula(i: &str) -> Formula
{
crate::parse::formula(i, &Declarations::new()).unwrap().1
}
fn format_formula(i: &str) -> String
{
format!("{}", formula(i))
}
#[test]
fn parse_formula_boolean()
{
assert_eq!(formula("true"), Formula::true_());
assert_eq!(formula("false"), Formula::false_());
}*/
#[test]
fn parse_predicate()
{
assert_eq!(predicate("s", &Declarations::new())
.map(|(i, x)| (i, x.declaration.name.clone())),
Ok(("", "s".to_string())));
assert_eq!(predicate("s", &Declarations::new())
.map(|(i, x)| (i, x.declaration.arity)),
Ok(("", 0)));
assert_eq!(predicate("s ( )", &Declarations::new())
.map(|(i, x)| (i, x.declaration.name.clone())),
Ok(("", "s".to_string())));
assert_eq!(predicate("s ( )", &Declarations::new())
.map(|(i, x)| (i, x.declaration.arity)),
Ok(("", 0)));
assert_eq!(predicate("s ( 1 , 2 , 3 )", &Declarations::new())
.map(|(i, x)| (i, x.declaration.name.clone())),
Ok(("", "s".to_string())));
assert_eq!(predicate("s ( 1 , 2 , 3 )", &Declarations::new())
.map(|(i, x)| (i, x.declaration.arity)),
Ok(("", 3)));
assert_eq!(predicate("s ( 1 , 2 , 3 )", &Declarations::new())
.map(|(i, mut x)| (i, x.arguments.remove(0))),
Ok(("", Box::new(Term::integer(1)))));
assert_eq!(predicate("s ( 1 , 2 , 3 )", &Declarations::new())
.map(|(i, mut x)| (i, x.arguments.remove(2))),
Ok(("", Box::new(Term::integer(3)))));
assert_eq!(predicate("s ( ), rest", &Declarations::new())
.map(|(i, x)| (i, x.declaration.name.clone())),
Ok((", rest", "s".to_string())));
assert_eq!(predicate("s ( ), rest", &Declarations::new())
.map(|(i, x)| (i, x.declaration.arity)),
Ok((", rest", 0)));
assert_eq!(predicate("s ( 1 , 2 , 3 ), rest", &Declarations::new())
.map(|(i, x)| (i, x.declaration.name.clone())),
Ok((", rest", "s".to_string())));
assert_eq!(predicate("s ( 1 , 2 , 3 ), rest", &Declarations::new())
.map(|(i, x)| (i, x.declaration.arity)),
Ok((", rest", 3)));
}
#[test]
fn parse_exists()
{
assert_eq!(exists("exists X (p(X, Y, X, Y)), rest", &Declarations::new())
.map(|(i, x)| (i, x.parameters.len())),
Ok((", rest", 1)));
assert!(exists("exists (p(X, Y, X, Y)), rest", &Declarations::new()).is_err());
assert!(exists("exists X, rest", &Declarations::new()).is_err());
assert!(exists("exists X (), rest", &Declarations::new()).is_err());
assert!(exists("exists X (, true), rest", &Declarations::new()).is_err());
assert!(exists("exists X (true, ), rest", &Declarations::new()).is_err());
assert!(exists("exists X (true false), rest", &Declarations::new()).is_err());
assert!(exists("exists X (true), rest", &Declarations::new()).is_ok());
assert!(exists("exists X p(X), rest", &Declarations::new()).is_err());
}
#[test]
fn parse_formula()
{
assert!(formula("exists X, Y (p(X, Y, X, Y) and X < Y and q(X) <-> r(X)), rest", &Declarations::new()).is_ok());
}
}