diff --git a/include/anthem/AST.h b/include/anthem/AST.h
index 41b0865..87c20d1 100644
--- a/include/anthem/AST.h
+++ b/include/anthem/AST.h
@@ -2,6 +2,7 @@
 #define __ANTHEM__AST_H
 
 #include <anthem/ASTForward.h>
+#include <anthem/Utils.h>
 
 namespace anthem
 {
@@ -369,6 +370,7 @@ struct VariableDeclaration
 	VariableDeclaration &operator=(VariableDeclaration &&other) = default;
 
 	Type type;
+	Domain domain{Domain::Unknown};
 	std::string name;
 };
 
diff --git a/include/anthem/Utils.h b/include/anthem/Utils.h
index 0c4f472..58c9dcf 100644
--- a/include/anthem/Utils.h
+++ b/include/anthem/Utils.h
@@ -33,6 +33,15 @@ enum class OperationResult
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+enum class Domain
+{
+	Noninteger,
+	Integer,
+	Unknown,
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 }
 
 #endif