Add domain specifier to variable declarations

With this change, the domain of variable declarations can be specified.
While the default is the general domain of all precomputed value, this
adds support for integer variables, for which advanced simplification
rules apply.

include/anthem/AST.h

@@ -343,13 +343,21 @@ struct VariableDeclaration
 		Body
 	};
 
+	enum class Domain
+	{
+		General,
+		Integer
+	};
+
 	explicit VariableDeclaration(Type type)
-	:	type{type}
+	:	type{type},
+		domain{Domain::General}
 	{
 	}
 
 	explicit VariableDeclaration(Type type, std::string &&name)
 	:	type{type},
+		domain{Domain::General},
 		name{std::move(name)}
 	{
 	}
@@ -360,6 +368,7 @@ struct VariableDeclaration
 	VariableDeclaration &operator=(VariableDeclaration &&other) = default;
 
 	Type type;
+	Domain domain;
 	std::string name;
 };
 

include/anthem/output/AST.h

@@ -323,7 +323,7 @@ inline output::ColorStream &print(output::ColorStream &stream, const Variable &v
 inline output::ColorStream &print(output::ColorStream &stream, const VariableDeclaration &variableDeclaration, PrintContext &printContext, bool)
 {
 	const auto printVariableDeclaration =
-		[&stream, &variableDeclaration](const auto *prefix, auto &variableIDs) -> output::ColorStream &
+		[&](const auto *prefix, auto &variableIDs) -> output::ColorStream &
 		{
 			auto matchingVariableID = variableIDs.find(&variableDeclaration);