Index: src/Common/utility.h
===================================================================
--- src/Common/utility.h	(revision 712348a6bab746947dbfecacd0d8d02b9ce19734)
+++ src/Common/utility.h	(revision d66e7b7b110efcf99370d5d03e97d25793df250a)
@@ -463,12 +463,18 @@
 std::pair<long long int, bool> eval(Expression * expr);
 
-// -----------------------------------------------------------------------------
-/// Reorders the input range in-place so that the minimal-value elements according to the 
-/// comparator are in front; 
+namespace ast {
+	class Expr;
+}
+
+std::pair<long long int, bool> eval(const ast::Expr * expr);
+
+// -----------------------------------------------------------------------------
+/// Reorders the input range in-place so that the minimal-value elements according to the
+/// comparator are in front;
 /// returns the iterator after the last minimal-value element.
 template<typename Iter, typename Compare>
 Iter sort_mins( Iter begin, Iter end, Compare& lt ) {
 	if ( begin == end ) return end;
-	
+
 	Iter min_pos = begin;
 	for ( Iter i = begin + 1; i != end; ++i ) {