From 78cc56dc46b92ff8562c751e187cf84516d4862c Mon Sep 17 00:00:00 2001
From: Ian Gulliver <ian@isinglasstheater.org>
Date: Sun, 29 Jun 2014 17:39:24 -0700
Subject: [PATCH] Make ZeroOrMore non-greedy to make it nestable without
 exponential behavior.

---
 grammars/mediawiki.js |  2 +-
 recentrunes.js        | 18 +++++++++---------
 test.js               |  5 +++--
 3 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/grammars/mediawiki.js b/grammars/mediawiki.js
index 02675b1..63e63aa 100644
--- a/grammars/mediawiki.js
+++ b/grammars/mediawiki.js
@@ -23,5 +23,5 @@ var mediawiki = {
       rr.Ref('nowiki'),
       rr.Ref('text')
    ),
-  'wikidoc': rr.Node('wikidoc', rr.ZeroOrMore(rr.Ref('wikichunk'))),
+  'wikidoc': rr.Node('wikidoc', rr.Sequence(rr.ZeroOrMore(rr.Ref('wikichunk')), rr.EndOfText())),
 };
diff --git a/recentrunes.js b/recentrunes.js
index 5f45b22..bab93bb 100644
--- a/recentrunes.js
+++ b/recentrunes.js
@@ -493,22 +493,18 @@ rr.ZeroOrMore_ = function(child) {
  */
 rr.ZeroOrMore_.prototype.match = function(context) {
   // Yield:
-  // 1) The results of SequentialPair(child, this)
-  // 2) An empty result
+  // 1) An empty result
+  // 2) The results of SequentialPair(child, this)
   // 3) Done
   //
-  // We must check for results from 1 that don't reduce context.remaining();
+  // We must check for results from 2 that don't reduce context.remaining();
   // that means infinite recursion.
 
-  var iterator = this.pair_.match(context);
+  var iterator = null;
   return {
     'next': function() {
       if (!iterator) {
-        return { 'done': true };
-      }
-      var next = iterator.next();
-      if (next['done']) {
-        iterator = null;
+        iterator = this.pair_.match(context);
         return {
           'done': false,
           'value': {
@@ -517,6 +513,10 @@ rr.ZeroOrMore_.prototype.match = function(context) {
           }
         };
       }
+      var next = iterator.next();
+      if (next['done']) {
+        return { 'done': true };
+      }
       if (next['value']['context'].remaining() == context.remaining()) {
         throw "Child of ZeroOrMore didn't consume input; grammar bug?";
       }
diff --git a/test.js b/test.js
index 89500fd..0dcb8a5 100644
--- a/test.js
+++ b/test.js
@@ -8,7 +8,7 @@ QUnit.test('Simple', function(assert) {
   var iterable = context.rules['wikidoc'].match(context);
   assert.equal(iterable.next().value.nodes[0].innerHTML,
       '<h3>Heading</h3>This is a wiki doc.\n' +
-      'How about some <b>bold and &lt;i&gt;bold italic&lt;/i&gt;</b>.\n' +
+      "How about some <b>bold and ''bold italic</b>''.\n" +
       'I would also love some nowiki &lt;b&gt;foo&lt;/b&gt;');
 });
 
@@ -16,7 +16,8 @@ QUnit.test('Simple', function(assert) {
 QUnit.test('ZeroOrMore', function(assert) {
   assert.expect(1);
   var rules = {
-    'test': rr.Node('test', rr.ZeroOrMore(rr.MultiLineText()))
+    'test': rr.Node('test',
+      rr.Sequence(rr.ZeroOrMore(rr.MultiLineText()), rr.EndOfText()))
   };
   var context = new rr.Context(rules, 'foobar');
   var iterable = context.rules['test'].match(context);