From b043fd4507db4a8cbdd67f9ccd5a0b7dba19ea21 Mon Sep 17 00:00:00 2001
From: cloudhead <alexis@cloudhead.io>
Date: Tue, 24 May 2011 17:05:17 -0400
Subject: [PATCH] catch errors on css function calls

---
 lib/less/parser.js    |  4 ++--
 lib/less/tree/call.js | 10 ++++++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/less/parser.js b/lib/less/parser.js
index 6d0da7b5..d83bb458 100644
--- a/lib/less/parser.js
+++ b/lib/less/parser.js
@@ -490,7 +490,7 @@ less.Parser = function Parser(env) {
                 // The arguments are parsed with the `entities.arguments` parser.
                 //
                 call: function () {
-                    var name, args;
+                    var name, args, index = i;
 
                     if (! (name = /^([\w-]+|%)\(/.exec(chunks[j]))) return;
 
@@ -507,7 +507,7 @@ less.Parser = function Parser(env) {
 
                     if (! $(')')) return;
 
-                    if (name) { return new(tree.Call)(name, args) }
+                    if (name) { return new(tree.Call)(name, args, index) }
                 },
                 arguments: function () {
                     var args = [], arg;
diff --git a/lib/less/tree/call.js b/lib/less/tree/call.js
index c2353e54..4a72932b 100644
--- a/lib/less/tree/call.js
+++ b/lib/less/tree/call.js
@@ -3,9 +3,10 @@
 //
 // A function call node.
 //
-tree.Call = function (name, args) {
+tree.Call = function (name, args, index) {
     this.name = name;
     this.args = args;
+    this.index = index;
 };
 tree.Call.prototype = {
     //
@@ -24,7 +25,12 @@ tree.Call.prototype = {
         var args = this.args.map(function (a) { return a.eval(env) });
 
         if (this.name in tree.functions) { // 1.
-            return tree.functions[this.name].apply(tree.functions, args);
+            try {
+                return tree.functions[this.name].apply(tree.functions, args);
+            } catch (e) {
+                throw { message: "error evaluating function `" + this.name + "`",
+                        index: this.index };
+            }
         } else { // 2.
             return new(tree.Anonymous)(this.name +
                    "(" + args.map(function (a) { return a.toCSS() }).join(', ') + ")");