private void VisitDoubleConstNode(double_const_node expr)
		{
			bw.Write(expr.constant_value);
		}
 public override void visit(SyntaxTree.double_const _double_const)
 {
     expression_node en = new double_const_node(_double_const.val, get_location(_double_const));
     switch (motivation_keeper.motivation)
     {
         case motivation.address_reciving: throw new CompilerInternalError("Addres reciving from constant"); break;
         case motivation.expression_evaluation: return_value(en); break;
         case motivation.semantic_node_reciving: return_semantic_value(en); break;
     }
     //return_value(en);
     return;
 }