Started implementing output simplifications.

app/main.cpp

@@ -16,6 +16,7 @@ int main(int argc, char **argv)
 		("help,h", "Display this help message")
 		("version,v", "Display version information")
 		("input,i", po::value<std::vector<std::string>>(), "Input files")
+		("simplify,s", po::bool_switch(&context.simplify), "Simplify the output")
 		("color,c", po::value<std::string>()->default_value("auto"), "Colorize output (always, never, auto)")
 		("log-priority,p", po::value<std::string>()->default_value("warning"), "Log messages starting from this priority (debug, info, warning, error)");
 

include/anthem/AST.h

@@ -397,168 +397,168 @@ const auto deepCopyVariantVector =
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-BinaryOperation deepCopy(const BinaryOperation &other)
+inline BinaryOperation deepCopy(const BinaryOperation &other)
 {
 	return BinaryOperation(other.operator_, deepCopy(other.left), deepCopy(other.right));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Boolean deepCopy(const Boolean &other)
+inline Boolean deepCopy(const Boolean &other)
 {
 	return Boolean(other.value);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Comparison deepCopy(const Comparison &other)
+inline Comparison deepCopy(const Comparison &other)
 {
 	return Comparison(other.operator_, deepCopy(other.left), deepCopy(other.right));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Constant deepCopy(const Constant &other)
+inline Constant deepCopy(const Constant &other)
 {
 	return Constant(std::string(other.name));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Function deepCopy(const Function &other)
+inline Function deepCopy(const Function &other)
 {
 	return Function(std::string(other.name), deepCopy(other.arguments));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Integer deepCopy(const Integer &other)
+inline Integer deepCopy(const Integer &other)
 {
 	return Integer(other.value);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Interval deepCopy(const Interval &other)
+inline Interval deepCopy(const Interval &other)
 {
 	return Interval(deepCopy(other.from), deepCopy(other.to));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Predicate deepCopy(const Predicate &other)
+inline Predicate deepCopy(const Predicate &other)
 {
 	return Predicate(std::string(other.name), deepCopy(other.arguments));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-SpecialInteger deepCopy(const SpecialInteger &other)
+inline SpecialInteger deepCopy(const SpecialInteger &other)
 {
 	return SpecialInteger(other.type);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-String deepCopy(const String &other)
+inline String deepCopy(const String &other)
 {
 	return String(std::string(other.text));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Variable deepCopy(const Variable &other)
+inline Variable deepCopy(const Variable &other)
 {
 	return Variable(std::string(other.name), other.type);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-std::vector<VariablePointer> deepCopy(const std::vector<VariablePointer> &other)
+inline std::vector<VariablePointer> deepCopy(const std::vector<VariablePointer> &other)
 {
 	return deepCopyUniquePtrVector(other);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-And deepCopy(const And &other)
+inline And deepCopy(const And &other)
 {
 	return And(deepCopy(other.arguments));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Biconditional deepCopy(const Biconditional &other)
+inline Biconditional deepCopy(const Biconditional &other)
 {
 	return Biconditional(deepCopy(other.left), deepCopy(other.right));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Exists deepCopy(const Exists &other)
+inline Exists deepCopy(const Exists &other)
 {
 	return Exists(deepCopy(other.variables), deepCopy(other.argument));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-ForAll deepCopy(const ForAll &other)
+inline ForAll deepCopy(const ForAll &other)
 {
 	return ForAll(deepCopy(other.variables), deepCopy(other.argument));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-In deepCopy(const In &other)
+inline In deepCopy(const In &other)
 {
 	return In(deepCopy(other.element), deepCopy(other.set));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Implies deepCopy(const Implies &other)
+inline Implies deepCopy(const Implies &other)
 {
 	return Implies(deepCopy(other.antecedent), deepCopy(other.consequent));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Not deepCopy(const Not &other)
+inline Not deepCopy(const Not &other)
 {
 	return Not(deepCopy(other.argument));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Or deepCopy(const Or &other)
+inline Or deepCopy(const Or &other)
 {
 	return Or(deepCopy(other.arguments));
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Formula deepCopy(const Formula &formula)
+inline Formula deepCopy(const Formula &formula)
 {
 	return deepCopyVariant(formula);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-std::vector<Formula> deepCopy(const std::vector<Formula> &formulas)
+inline std::vector<Formula> deepCopy(const std::vector<Formula> &formulas)
 {
 	return deepCopyVariantVector(formulas);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Term deepCopy(const Term &term)
+inline Term deepCopy(const Term &term)
 {
 	return deepCopyVariant(term);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-std::vector<Term> deepCopy(const std::vector<Term> &terms)
+inline std::vector<Term> deepCopy(const std::vector<Term> &terms)
 {
 	return deepCopyVariantVector(terms);
 }

include/anthem/Context.h

@@ -30,6 +30,8 @@ struct Context
 	bool isChoiceRule = false;
 	size_t numberOfHeadLiterals = 0;
 	size_t auxiliaryBodyLiteralID = 1;
+
+	bool simplify = false;
 };
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////

include/anthem/Simplification.h

@@ -0,0 +1,21 @@
+#ifndef __ANTHEM__SIMPLIFICATION_H
+#define __ANTHEM__SIMPLIFICATION_H
+
+#include <anthem/AST.h>
+
+namespace anthem
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// Simplification
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+ast::Formula simplify(ast::Formula &&formula);
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}
+
+#endif

src/anthem/Simplification.cpp

@@ -0,0 +1,127 @@
+#include <anthem/Simplification.h>
+
+namespace anthem
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// Simplification
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+bool isPrimitiveTerm(const ast::Term &term)
+{
+	const auto binaryOperationIsNotPrimitiveTerm =
+		[](const ast::BinaryOperationPointer &)
+		{
+			return false;
+		};
+
+	const auto intervalIsNotPrimitiveTerm =
+		[](const ast::IntervalPointer &)
+		{
+			return false;
+		};
+
+	const auto defaultIsPrimitiveTerm =
+		[](const auto &)
+		{
+			return true;
+		};
+
+	return term.match(binaryOperationIsNotPrimitiveTerm, intervalIsNotPrimitiveTerm, defaultIsPrimitiveTerm);
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+ast::Formula simplifyFormula(ast::Formula &&formula)
+{
+	const auto simplifyAnd =
+		[&](ast::AndPointer &and_) -> ast::Formula
+		{
+			for (auto &argument : and_->arguments)
+				argument = simplifyFormula(std::move(argument));
+
+			return std::move(and_);
+		};
+
+	const auto simplifyBiconditional =
+		[&](ast::BiconditionalPointer &biconditional) -> ast::Formula
+		{
+			biconditional->left = simplifyFormula(std::move(biconditional->left));
+			biconditional->right = simplifyFormula(std::move(biconditional->right));
+
+			return std::move(biconditional);
+		};
+
+	const auto simplifyExists =
+		[&](ast::ExistsPointer &exists) -> ast::Formula
+		{
+			exists->argument = simplifyFormula(std::move(exists->argument));
+
+			return std::move(exists);
+		};
+
+	const auto simplifyForAll =
+		[&](ast::ForAllPointer &forAll) -> ast::Formula
+		{
+			forAll->argument = simplifyFormula(std::move(forAll->argument));
+
+			return std::move(forAll);
+		};
+
+	const auto simplifyImplies =
+		[&](ast::ImpliesPointer &implies) -> ast::Formula
+		{
+			implies->antecedent = simplifyFormula(std::move(implies->antecedent));
+			implies->consequent = simplifyFormula(std::move(implies->consequent));
+
+			return std::move(implies);
+		};
+
+	const auto simplifyIn =
+		[](ast::InPointer &in) -> ast::Formula
+		{
+			if (!isPrimitiveTerm(in->element) || !isPrimitiveTerm(in->set))
+				return std::move(in);
+
+			// Simplify formulas of type “A in B” to “A = B” if A and B are primitive
+			return std::make_unique<ast::Comparison>(ast::Comparison::Operator::Equal, std::move(in->element), std::move(in->set));
+		};
+
+	const auto simplifyNot =
+		[&](ast::NotPointer &not_) -> ast::Formula
+		{
+			not_->argument = simplifyFormula(std::move(not_->argument));
+
+			return std::move(not_);
+		};
+
+	const auto simplifyOr =
+		[&](ast::OrPointer &or_) -> ast::Formula
+		{
+			for (auto &argument : or_->arguments)
+				argument = simplifyFormula(std::move(argument));
+
+			return std::move(or_);
+		};
+
+	const auto defaultDoNothing =
+		[&](auto &x) -> ast::Formula
+		{
+			return std::move(x);
+		};
+
+	return formula.match(simplifyAnd, simplifyBiconditional, simplifyExists, simplifyForAll, simplifyImplies, simplifyIn, simplifyNot, simplifyOr, defaultDoNothing);
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+ast::Formula simplify(ast::Formula &&formula)
+{
+	return simplifyFormula(std::move(formula));
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}

src/anthem/Translation.cpp

@@ -7,6 +7,7 @@
 #include <clingo.hh>
 
 #include <anthem/Context.h>
+#include <anthem/Simplification.h>
 #include <anthem/StatementVisitor.h>
 #include <anthem/output/AST.h>
 
@@ -41,12 +42,19 @@ void translate(const char *fileName, std::istream &stream, Context &context)
 	const auto translateStatement =
 		[&context](const Clingo::AST::Statement &statement)
 		{
-			const auto formula = statement.data.accept(StatementVisitor(), statement, context);
+			auto formula = statement.data.accept(StatementVisitor(), statement, context);
 
 			if (!formula)
 				return;
 
-			context.logger.outputStream() << formula.value() << std::endl;
+			if (!context.simplify)
+			{
+				context.logger.outputStream() << formula.value() << std::endl;
+				return;
+			}
+
+			auto simplifiedFormula = simplify(std::move(formula.value()));
+			context.logger.outputStream() << simplifiedFormula << std::endl;
 		};
 
 	const auto logger =