Replace SimplificationResult with OperationResult

This replaces the SimplificationResult enum class with OperationResult.
The rationale is that this type, which just reports whether or not an
operation actually changed the input data, is not simplification-
specific and will be used for integer variable detection as well.

include/anthem/Simplification.h

@@ -12,14 +12,6 @@ namespace anthem
 //
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-enum class SimplificationResult
-{
-	Simplified,
-	Unchanged,
-};
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
 void simplify(ast::Formula &formula);
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////

include/anthem/SimplificationVisitors.h

@@ -3,6 +3,7 @@
 
 #include <anthem/AST.h>
 #include <anthem/Simplification.h>
+#include <anthem/Utils.h>
 
 namespace anthem
 {
@@ -19,96 +20,96 @@ template<class T>
 struct FormulaSimplificationVisitor
 {
 	template <class... Arguments>
-	SimplificationResult visit(And &and_, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(And &and_, Formula &formula, Arguments &&... arguments)
 	{
 		for (auto &argument : and_.arguments)
-			if (argument.accept(*this, argument, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+			if (argument.accept(*this, argument, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-				return SimplificationResult::Simplified;
+				return OperationResult::Changed;
 
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Biconditional &biconditional, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(Biconditional &biconditional, Formula &formula, Arguments &&... arguments)
 	{
-		if (biconditional.left.accept(*this, biconditional.left, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (biconditional.left.accept(*this, biconditional.left, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
-		if (biconditional.right.accept(*this, biconditional.right, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (biconditional.right.accept(*this, biconditional.right, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Boolean &, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(Boolean &, Formula &formula, Arguments &&... arguments)
 	{
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Comparison &, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(Comparison &, Formula &formula, Arguments &&... arguments)
 	{
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Exists &exists, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(Exists &exists, Formula &formula, Arguments &&... arguments)
 	{
-		if (exists.argument.accept(*this, exists.argument, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (exists.argument.accept(*this, exists.argument, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(ForAll &forAll, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(ForAll &forAll, Formula &formula, Arguments &&... arguments)
 	{
-		if (forAll.argument.accept(*this, forAll.argument, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (forAll.argument.accept(*this, forAll.argument, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Implies &implies, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(Implies &implies, Formula &formula, Arguments &&... arguments)
 	{
-		if (implies.antecedent.accept(*this, implies.antecedent, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (implies.antecedent.accept(*this, implies.antecedent, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
-		if (implies.consequent.accept(*this, implies.consequent, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (implies.consequent.accept(*this, implies.consequent, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(In &, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(In &, Formula &formula, Arguments &&... arguments)
 	{
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Not &not_, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(Not &not_, Formula &formula, Arguments &&... arguments)
 	{
-		if (not_.argument.accept(*this, not_.argument, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (not_.argument.accept(*this, not_.argument, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Or &or_, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(Or &or_, Formula &formula, Arguments &&... arguments)
 	{
 		for (auto &argument : or_.arguments)
-			if (argument.accept(*this, argument, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+			if (argument.accept(*this, argument, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-				return SimplificationResult::Simplified;
+				return OperationResult::Changed;
 
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Predicate &, Formula &formula, Arguments &&... arguments)
+	OperationResult visit(Predicate &, Formula &formula, Arguments &&... arguments)
 	{
 		return T::accept(formula, std::forward<Arguments>(arguments)...);
 	}
@@ -116,69 +117,69 @@ struct FormulaSimplificationVisitor
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-template<class T, class SimplificationResult = void>
+template<class T, class OperationResult = void>
 struct TermSimplificationVisitor
 {
 	template <class... Arguments>
-	SimplificationResult visit(BinaryOperation &binaryOperation, Term &term, Arguments &&... arguments)
+	OperationResult visit(BinaryOperation &binaryOperation, Term &term, Arguments &&... arguments)
 	{
-		if (binaryOperation.left.accept(*this, binaryOperation.left, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (binaryOperation.left.accept(*this, binaryOperation.left, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
-		if (binaryOperation.right.accept(*this, binaryOperation.right, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (binaryOperation.right.accept(*this, binaryOperation.right, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
 		return T::accept(term, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Boolean &, Term &term, Arguments &&... arguments)
+	OperationResult visit(Boolean &, Term &term, Arguments &&... arguments)
 	{
 		return T::accept(term, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Function &function, Term &term, Arguments &&... arguments)
+	OperationResult visit(Function &function, Term &term, Arguments &&... arguments)
 	{
 		for (auto &argument : function.arguments)
-			if (argument.accept(*this, argument, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+			if (argument.accept(*this, argument, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-				return SimplificationResult::Simplified;
+				return OperationResult::Changed;
 
 		return T::accept(term, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Integer &, Term &term, Arguments &&... arguments)
+	OperationResult visit(Integer &, Term &term, Arguments &&... arguments)
 	{
 		return T::accept(term, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Interval &interval, Term &term, Arguments &&... arguments)
+	OperationResult visit(Interval &interval, Term &term, Arguments &&... arguments)
 	{
-		if (interval.from.accept(*this, interval.from, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (interval.from.accept(*this, interval.from, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
-		if (interval.to.accept(*this, interval.to, std::forward<Arguments>(arguments)...) == SimplificationResult::Simplified)
+		if (interval.to.accept(*this, interval.to, std::forward<Arguments>(arguments)...) == OperationResult::Changed)
-			return SimplificationResult::Simplified;
+			return OperationResult::Changed;
 
 		return T::accept(term, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(SpecialInteger &, Term &term, Arguments &&... arguments)
+	OperationResult visit(SpecialInteger &, Term &term, Arguments &&... arguments)
 	{
 		return T::accept(term, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(String &, Term &term, Arguments &&... arguments)
+	OperationResult visit(String &, Term &term, Arguments &&... arguments)
 	{
 		return T::accept(term, std::forward<Arguments>(arguments)...);
 	}
 
 	template <class... Arguments>
-	SimplificationResult visit(Variable &, Term &term, Arguments &&... arguments)
+	OperationResult visit(Variable &, Term &term, Arguments &&... arguments)
 	{
 		return T::accept(term, std::forward<Arguments>(arguments)...);
 	}

include/anthem/Utils.h

@@ -32,6 +32,14 @@ enum class Tristate
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+enum class OperationResult
+{
+	Unchanged,
+	Changed,
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 }
 
 #endif

src/anthem/Simplification.cpp

@@ -100,7 +100,7 @@ struct ReplaceVariableInFormulaVisitor : public ast::RecursiveFormulaVisitor<Rep
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 template<class SimplificationRule>
-SimplificationResult simplify(ast::Formula &formula)
+OperationResult simplify(ast::Formula &formula)
 {
 	return SimplificationRule::apply(formula);
 }
@@ -108,10 +108,10 @@ SimplificationResult simplify(ast::Formula &formula)
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 template<class FirstSimplificationRule, class SecondSimplificationRule, class... OtherSimplificationRules>
-SimplificationResult simplify(ast::Formula &formula)
+OperationResult simplify(ast::Formula &formula)
 {
-	if (simplify<FirstSimplificationRule>(formula) == SimplificationResult::Simplified)
+	if (simplify<FirstSimplificationRule>(formula) == OperationResult::Changed)
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 
 	return simplify<SecondSimplificationRule, OtherSimplificationRules...>(formula);
 }
@@ -122,19 +122,19 @@ struct SimplificationRuleExistsWithoutQuantifiedVariables
 {
 	static constexpr const auto Description = "exists () (F) === F";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::Exists>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &exists = formula.get<ast::Exists>();
 
 		if (!exists.variables.empty())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		formula = std::move(exists.argument);
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -144,20 +144,20 @@ struct SimplificationRuleTrivialAssignmentInExists
 {
 	static constexpr const auto Description = "exists X (X = Y) === #true";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::Exists>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		const auto &exists = formula.get<ast::Exists>();
 
 		if (!exists.argument.is<ast::Comparison>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		const auto &comparison = exists.argument.get<ast::Comparison>();
 
 		if (comparison.operator_ != ast::Comparison::Operator::Equal)
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		const auto matchingAssignment = std::find_if(exists.variables.cbegin(), exists.variables.cend(),
 			[&](const auto &variableDeclaration)
@@ -167,11 +167,11 @@ struct SimplificationRuleTrivialAssignmentInExists
 			});
 
 		if (matchingAssignment == exists.variables.cend())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		formula = ast::Formula::make<ast::Boolean>(true);
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -181,20 +181,20 @@ struct SimplificationRuleAssignmentInExists
 {
 	static constexpr const auto Description = "exists X (X = t and F(X)) === exists () (F(t))";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::Exists>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &exists = formula.get<ast::Exists>();
 
 		if (!exists.argument.is<ast::And>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &and_ = exists.argument.get<ast::And>();
 		auto &arguments = and_.arguments;
 
-		auto simplificationResult = SimplificationResult::Unchanged;
+		auto simplificationResult = OperationResult::Unchanged;
 
 		for (auto i = exists.variables.begin(); i != exists.variables.end();)
 		{
@@ -225,7 +225,7 @@ struct SimplificationRuleAssignmentInExists
 				arguments.erase(j);
 
 				wasVariableReplaced = true;
-				simplificationResult = SimplificationResult::Simplified;
+				simplificationResult = OperationResult::Changed;
 
 				break;
 			}
@@ -249,19 +249,19 @@ struct SimplificationRuleEmptyConjunction
 {
 	static constexpr const auto Description = "[empty conjunction] === #true";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::And>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &and_ = formula.get<ast::And>();
 
 		if (!and_.arguments.empty())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		formula = ast::Formula::make<ast::Boolean>(true);
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -271,19 +271,19 @@ struct SimplificationRuleOneElementConjunction
 {
 	static constexpr const auto Description = "[conjunction of only F] === F";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::And>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &and_ = formula.get<ast::And>();
 
 		if (and_.arguments.size() != 1)
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		formula = std::move(and_.arguments.front());
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -293,19 +293,19 @@ struct SimplificationRuleTrivialExists
 {
 	static constexpr const auto Description = "exists ... ([#true/#false]) === [#true/#false]";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::Exists>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &exists = formula.get<ast::Exists>();
 
 		if (!exists.argument.is<ast::Boolean>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		formula = std::move(exists.argument);
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -315,21 +315,21 @@ struct SimplificationRuleInWithPrimitiveArguments
 {
 	static constexpr const auto Description = "[primitive A] in [primitive B] === A = B";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::In>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &in = formula.get<ast::In>();
 
 		assert(ast::isPrimitive(in.element));
 
 		if (!ast::isPrimitive(in.element) || !ast::isPrimitive(in.set))
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		formula = ast::Comparison(ast::Comparison::Operator::Equal, std::move(in.element), std::move(in.set));
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -339,10 +339,10 @@ struct SimplificationRuleSubsumptionInBiconditionals
 {
 	static constexpr const auto Description = "(F <-> (F and G)) === (F -> G)";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::Biconditional>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &biconditional = formula.get<ast::Biconditional>();
 
@@ -353,7 +353,7 @@ struct SimplificationRuleSubsumptionInBiconditionals
 		const auto rightIsAnd = biconditional.right.is<ast::And>();
 
 		if (!(leftIsPredicate && rightIsAnd) && !(rightIsPredicate && leftIsAnd))
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &predicateSide = (leftIsPredicate ? biconditional.left : biconditional.right);
 		auto &andSide = (leftIsPredicate ? biconditional.right : biconditional.left);
@@ -367,13 +367,13 @@ struct SimplificationRuleSubsumptionInBiconditionals
 			});
 
 		if (matchingPredicate == and_.arguments.cend())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		and_.arguments.erase(matchingPredicate);
 
 		formula = ast::Formula::make<ast::Implies>(std::move(predicateSide), std::move(andSide));
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -383,21 +383,21 @@ struct SimplificationRuleDoubleNegation
 {
 	static constexpr const auto Description = "not not F === F";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::Not>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &not_ = formula.get<ast::Not>();
 
 		if (!not_.argument.is<ast::Not>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &notNot = not_.argument.get<ast::Not>();
 
 		formula = std::move(notNot.argument);
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -407,15 +407,15 @@ struct SimplificationRuleDeMorganForConjunctions
 {
 	static constexpr const auto Description = "(not (F and G)) === (not F or not G)";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::Not>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &not_ = formula.get<ast::Not>();
 
 		if (!not_.argument.is<ast::And>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &and_ = not_.argument.get<ast::And>();
 
@@ -424,7 +424,7 @@ struct SimplificationRuleDeMorganForConjunctions
 
 		formula = ast::Formula::make<ast::Or>(std::move(and_.arguments));
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -434,21 +434,21 @@ struct SimplificationRuleImplicationFromDisjunction
 {
 	static constexpr const auto Description = "(not F or G) === (F -> G)";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::Or>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &or_ = formula.get<ast::Or>();
 
 		if (or_.arguments.size() != 2)
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		const auto leftIsNot = or_.arguments[0].is<ast::Not>();
 		const auto rightIsNot = or_.arguments[1].is<ast::Not>();
 
 		if (leftIsNot == rightIsNot)
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &negativeSide = leftIsNot ? or_.arguments[0] : or_.arguments[1];
 		auto &positiveSide = leftIsNot ? or_.arguments[1] : or_.arguments[0];
@@ -460,7 +460,7 @@ struct SimplificationRuleImplicationFromDisjunction
 
 		formula = ast::Formula::make<ast::Implies>(std::move(negativeSideArgument), std::move(positiveSide));
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -470,15 +470,15 @@ struct SimplificationRuleNegatedComparison
 {
 	static constexpr const auto Description = "(not F [comparison] G) === (F [negated comparison] G)";
 
-	static SimplificationResult apply(ast::Formula &formula)
+	static OperationResult apply(ast::Formula &formula)
 	{
 		if (!formula.is<ast::Not>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &not_ = formula.get<ast::Not>();
 
 		if (!not_.argument.is<ast::Comparison>())
-			return SimplificationResult::Unchanged;
+			return OperationResult::Unchanged;
 
 		auto &comparison = not_.argument.get<ast::Comparison>();
 
@@ -506,7 +506,7 @@ struct SimplificationRuleNegatedComparison
 
 		formula = std::move(comparison);
 
-		return SimplificationResult::Simplified;
+		return OperationResult::Changed;
 	}
 };
 
@@ -535,7 +535,7 @@ const auto simplifyWithDefaultRules =
 struct SimplifyFormulaVisitor : public ast::FormulaSimplificationVisitor<SimplifyFormulaVisitor>
 {
 	// Do nothing for all other types of expressions
-	static SimplificationResult accept(ast::Formula &formula)
+	static OperationResult accept(ast::Formula &formula)
 	{
 		return simplifyWithDefaultRules(formula);
 	}
@@ -545,7 +545,7 @@ struct SimplifyFormulaVisitor : public ast::FormulaSimplificationVisitor<Simplif
 
 void simplify(ast::Formula &formula)
 {
-	while (formula.accept(SimplifyFormulaVisitor(), formula) == SimplificationResult::Simplified);
+	while (formula.accept(SimplifyFormulaVisitor(), formula) == OperationResult::Changed);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////