Provide function for evaluating formulas

This provides a new function that can be used to evaluate formulas under
partial knowledge about the individual variables’ assignments.

This will be useful for testing whether formulas or subformulas become
trivial under specific interpretations.

include/anthem/Type.h

@@ -2,6 +2,7 @@
 #define __ANTHEM__TYPE_H
 
 #include <anthem/AST.h>
+#include <anthem/ASTUtils.h>
 #include <anthem/Utils.h>
 
 namespace anthem
@@ -13,16 +14,6 @@ namespace anthem
 //
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-struct DefaultVariableDomainAccessor
-{
-	Domain operator()(const ast::Variable &variable)
-	{
-		return variable.declaration->domain;
-	}
-};
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
 template <class VariableDomainAccessor = DefaultVariableDomainAccessor, class... Arguments>
 Type type(const ast::Term &term, Arguments &&... arguments);