From 188ad03c1739d1b72343f20d707bfb6e78980f6d Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas <jashkenas@gmail.com>
Date: Tue, 9 Nov 2010 00:36:13 -0500
Subject: [PATCH] coco b615379: optimized @ensureBalance

---
 lib/rewriter.js     | 40 +++++++++++++++-------------------------
 src/rewriter.coffee | 17 +++++++----------
 2 files changed, 22 insertions(+), 35 deletions(-)

diff --git a/lib/rewriter.js b/lib/rewriter.js
index 14a3b644..30c818cf 100644
--- a/lib/rewriter.js
+++ b/lib/rewriter.js
@@ -253,42 +253,32 @@
     });
   };
   exports.Rewriter.prototype.ensureBalance = function(pairs) {
-    var key, levels, open, openLine, unclosed, value, _results;
+    var close, level, levels, open, openLine, tag, token, _i, _j, _len, _len2, _ref, _ref2;
     levels = {};
     openLine = {};
-    this.scanTokens(function(token, i) {
-      var close, open, tag, _i, _len, _ref;
+    _ref = this.tokens;
+    for (_i = 0, _len = _ref.length; _i < _len; _i++) {
+      token = _ref[_i];
       tag = token[0];
-      for (_i = 0, _len = pairs.length; _i < _len; _i++) {
-        _ref = pairs[_i], open = _ref[0], close = _ref[1];
+      for (_j = 0, _len2 = pairs.length; _j < _len2; _j++) {
+        _ref2 = pairs[_j], open = _ref2[0], close = _ref2[1];
         levels[open] |= 0;
         if (tag === open) {
-          if (levels[open] === 0) {
+          if (levels[open]++ === 0) {
             openLine[open] = token[2];
           }
-          levels[open] += 1;
-        } else if (tag === close) {
-          levels[open] -= 1;
-        }
-        if (levels[open] < 0) {
+        } else if (tag === close && --levels[open] < 0) {
           throw Error("too many " + token[1] + " on line " + (token[2] + 1));
         }
       }
-      return 1;
-    });
-    unclosed = ((function() {
-      _results = [];
-      for (key in levels) {
-        value = levels[key];
-        if (value > 0) {
-          _results.push(key);
-        }
-      }
-      return _results;
-    })());
-    if (unclosed.length) {
-      throw Error("unclosed " + (open = unclosed[0]) + " on line " + (openLine[open] + 1));
     }
+    for (open in levels) {
+      level = levels[open];
+      if (level > 0) {
+        throw Error("unclosed " + open + " on line " + (openLine[open] + 1));
+      }
+    }
+    return this;
   };
   exports.Rewriter.prototype.rewriteClosingParens = function() {
     var debt, key, stack;
diff --git a/src/rewriter.coffee b/src/rewriter.coffee
index 41cd3fc7..50e9ec77 100644
--- a/src/rewriter.coffee
+++ b/src/rewriter.coffee
@@ -204,20 +204,17 @@ class exports.Rewriter
   ensureBalance: (pairs) ->
     levels   = {}
     openLine = {}
-    @scanTokens (token, i) ->
+    for token in @tokens
       [tag] = token
       for [open, close] in pairs
         levels[open] |= 0
         if tag is open
-          openLine[open] = token[2] if levels[open] is 0
-          levels[open] += 1
-        else if tag is close
-          levels[open] -= 1
-        throw Error "too many #{token[1]} on line #{token[2] + 1}" if levels[open] < 0
-      1
-    unclosed = (key for all key, value of levels when value > 0)
-    if unclosed.length
-      throw Error "unclosed #{ open = unclosed[0] } on line #{openLine[open] + 1}"
+          openLine[open] = token[2] if levels[open]++ is 0
+        else if tag is close and --levels[open] < 0
+          throw Error "too many #{token[1]} on line #{token[2] + 1}"
+    for all open, level of levels when level > 0
+      throw Error "unclosed #{ open } on line #{openLine[open] + 1}"
+    this
 
   # We'd like to support syntax like this:
   #