From 664a57ec688840950db9010f7474d87898210ae6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Patrick=20L=C3=BChne?= <patrick-github@luehne.de>
Date: Tue, 30 May 2017 18:09:33 +0200
Subject: [PATCH] Fixed issue with multi-layer variable stacks.

---
 include/anthem/Body.h     |  7 +++++--
 src/anthem/ASTUtils.cpp   |  4 ++--
 tests/TestTranslation.cpp | 16 ++++++++++++++++
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/include/anthem/Body.h b/include/anthem/Body.h
index 8c78ef7..003cd49 100644
--- a/include/anthem/Body.h
+++ b/include/anthem/Body.h
@@ -62,11 +62,12 @@ struct BodyTermTranslateVisitor
 		std::vector<std::unique_ptr<ast::VariableDeclaration>> parameters;
 		parameters.reserve(function.arguments.size());
 
-		variableStack.push(&parameters);
-
 		for (size_t i = 0; i < function.arguments.size(); i++)
 			parameters.emplace_back(std::make_unique<ast::VariableDeclaration>(ast::VariableDeclaration::Type::Body));
 
+		// TODO: implement pushing with scoped guards to avoid bugs
+		variableStack.push(&parameters);
+
 		ast::And conjunction;
 
 		for (size_t i = 0; i < function.arguments.size(); i++)
@@ -75,6 +76,8 @@ struct BodyTermTranslateVisitor
 			conjunction.arguments.emplace_back(ast::Formula::make<ast::In>(ast::Variable(parameters[i].get()), translate(argument, context, ruleContext, variableStack)));
 		}
 
+		variableStack.pop();
+
 		ast::Predicate predicate(std::string(function.name));
 		predicate.arguments.reserve(function.arguments.size());
 
diff --git a/src/anthem/ASTUtils.cpp b/src/anthem/ASTUtils.cpp
index 4ae6d4d..0cc7c86 100644
--- a/src/anthem/ASTUtils.cpp
+++ b/src/anthem/ASTUtils.cpp
@@ -29,7 +29,7 @@ void VariableStack::pop()
 
 std::experimental::optional<ast::VariableDeclaration *> VariableStack::findUserVariableDeclaration(const char *variableName) const
 {
-	const auto variableNameMatches =
+	const auto variableDeclarationMatches =
 		[&variableName](const auto &variableDeclaration)
 		{
 			return variableDeclaration->type == VariableDeclaration::Type::UserDefined
@@ -39,7 +39,7 @@ std::experimental::optional<ast::VariableDeclaration *> VariableStack::findUserV
 	for (auto i = m_layers.rbegin(); i != m_layers.rend(); i++)
 	{
 		auto &layer = **i;
-		const auto matchingVariableDeclaration = std::find_if(layer.begin(), layer.end(), variableNameMatches);
+		const auto matchingVariableDeclaration = std::find_if(layer.begin(), layer.end(), variableDeclarationMatches);
 
 		if (matchingVariableDeclaration != layer.end())
 			return matchingVariableDeclaration->get();
diff --git a/tests/TestTranslation.cpp b/tests/TestTranslation.cpp
index e2355b6..38bd4d0 100644
--- a/tests/TestTranslation.cpp
+++ b/tests/TestTranslation.cpp
@@ -181,6 +181,22 @@ TEST_CASE("[translation] Rules are translated correctly", "[translation]")
 		CHECK(output.str() == "((V1 in U1 and V2 in 1..10 and exists X1, X2 (X1 in U1 and X2 in 6..12 and q(X1, X2))) -> p(V1, V2))\n");
 	}
 
+	SECTION("intervals with variable")
+	{
+		input << ":- q(N), 1 = 1..N.";
+		anthem::translate("input", input, context);
+
+		CHECK(output.str() == "((exists X1 (X1 in U1 and q(X1)) and exists X2, X3 (X2 in 1 and X3 in 1..U1 and X2 = X3)) -> #false)\n");
+	}
+
+	SECTION("intervals with two variables")
+	{
+		input << ":- q(M, N), M = 1..N.";
+		anthem::translate("input", input, context);
+
+		CHECK(output.str() == "((exists X1, X2 (X1 in U1 and X2 in U2 and q(X1, X2)) and exists X3, X4 (X3 in U1 and X4 in 1..U2 and X3 = X4)) -> #false)\n");
+	}
+
 	SECTION("comparisons")
 	{
 		input << "p(M, N, O, P) :- M < N, P != O.";