From e0e72209f085334819000467d1dcdcaaa5570c17 Mon Sep 17 00:00:00 2001
From: Andreas Lind Petersen <andreas@one.com>
Date: Sun, 31 Mar 2013 18:30:28 +0200
Subject: [PATCH] Declare JS_Parse_Error and DefaultsError the same way, make
 both instanceof Error, and also capture a stack trace in the DefaultsError
 constructor.

---
 lib/parse.js | 9 ++++-----
 lib/utils.js | 8 ++++++--
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/lib/parse.js b/lib/parse.js
index da39b5b1..22c0aa8d 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -178,16 +178,15 @@ function parse_js_number(num) {
 };
 
 function JS_Parse_Error(message, line, col, pos) {
-    this.message = message;
+    this.message = message + " (line: " + line + ", col: " + col + ", pos: " + pos + ")";
     this.line = line;
     this.col = col;
     this.pos = pos;
-    this.stack = new Error().stack;
+    // The second parameter omits the JS_Parse_Error constructor from the captured stack trace:
+    Error.captureStackTrace(this, JS_Parse_Error);
 };
 
-JS_Parse_Error.prototype.toString = function() {
-    return this.message + " (line: " + this.line + ", col: " + this.col + ", pos: " + this.pos + ")" + "\n\n" + this.stack;
-};
+JS_Parse_Error.prototype = Error.prototype;
 
 function js_error(message, filename, line, col, pos) {
     throw new JS_Parse_Error(message, line, col, pos);
diff --git a/lib/utils.js b/lib/utils.js
index c95b9824..42bd5ffa 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -81,11 +81,15 @@ function repeat_string(str, i) {
     return d;
 };
 
-function DefaultsError(msg, defs) {
-    this.msg = msg;
+function DefaultsError(message, defs) {
+    this.message = message + "(defs: " + JSON.stringify(defs) + ")";
     this.defs = defs;
+    // The second parameter omits the DefaultError constructor from the captured stack trace:
+    Error.captureStackTrace(this, DefaultsError);
 };
 
+DefaultsError.prototype = Error.prototype;
+
 function defaults(args, defs, croak) {
     if (args === true)
         args = {};