Making sure to evaluate a functions args even if it's just being passed through.

eval_apply.cpp

@@ -291,8 +291,16 @@ namespace Sass {
       case Node::function_call: {
         // TO DO: default-constructed Function should be a generic callback (maybe)
         pair<string, size_t> sig(expr[0].token().to_string(), expr[1].size());
-        if (!f_env.count(sig)) return expr; // TO DO: EVAL THE ARGUMENTS
-        else                   return apply_function(f_env[sig], expr[1], prefix, env, f_env, new_Node, ctx);
+        if (!f_env.count(sig)) {
+          Node args(expr[1]);
+          for (size_t i = 0, S = args.size(); i < S; ++i) {
+            args[i] = eval(args[i], prefix, env, f_env, new_Node, ctx);
+          }
+          return expr;
+        }
+        else {
+          return apply_function(f_env[sig], expr[1], prefix, env, f_env, new_Node, ctx);
+        }
       } break;
       
       case Node::unary_plus: {