From a64afe61622094e1eee160d231dbdba18584d844 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas <jashkenas@gmail.com>
Date: Mon, 22 Feb 2010 19:22:09 -0500
Subject: [PATCH] fixing the trailing-else-in-switch-getting-sucked-in-bug,
 Issue 195.

---
 lib/grammar.js          |  2 +-
 lib/nodes.js            | 12 +++++++++---
 lib/parser.js           |  2 +-
 src/grammar.coffee      |  2 +-
 src/nodes.coffee        |  9 ++++++---
 test/test_switch.coffee | 10 ++++++++++
 6 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/lib/grammar.js b/lib/grammar.js
index 4ff0021a..f8537eb9 100644
--- a/lib/grammar.js
+++ b/lib/grammar.js
@@ -462,7 +462,7 @@
     Switch: [o("SWITCH Expression INDENT Whens OUTDENT", function() {
         return $4.rewrite_condition($2);
       }), o("SWITCH Expression INDENT Whens ELSE Block OUTDENT", function() {
-        return $4.rewrite_condition($2).add_else($6);
+        return $4.rewrite_condition($2).add_else($6, true);
       })
     ],
     // The inner list of whens.
diff --git a/lib/nodes.js b/lib/nodes.js
index b28879b5..9374746e 100644
--- a/lib/nodes.js
+++ b/lib/nodes.js
@@ -1246,9 +1246,15 @@
       return this;
     },
     // Rewrite a chain of IfNodes to add a default case as the final else.
-    add_else: function add_else(exprs) {
-      this.is_chain() ? this.else_body.add_else(exprs) : (this.else_body = exprs && exprs.unwrap());
-      this.children.push(exprs);
+    add_else: function add_else(exprs, statement) {
+      if (this.is_chain()) {
+        this.else_body.add_else(exprs);
+      } else {
+        if (!(statement)) {
+          exprs = exprs.unwrap();
+        }
+        this.children.push((this.else_body = exprs));
+      }
       return this;
     },
     // If the else_body is an IfNode itself, then we've got an if-else chain.
diff --git a/lib/parser.js b/lib/parser.js
index 6eeb5cf2..9bd10a12 100755
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -356,7 +356,7 @@ case 167:this.$ = (function () {
 break;
 case 168:this.$ = $$[$0-5+4-1].rewrite_condition($$[$0-5+2-1]);
 break;
-case 169:this.$ = $$[$0-7+4-1].rewrite_condition($$[$0-7+2-1]).add_else($$[$0-7+6-1]);
+case 169:this.$ = $$[$0-7+4-1].rewrite_condition($$[$0-7+2-1]).add_else($$[$0-7+6-1], true);
 break;
 case 170:this.$ = $$[$0-1+1-1];
 break;
diff --git a/src/grammar.coffee b/src/grammar.coffee
index 6fb430d5..ce8b99e1 100644
--- a/src/grammar.coffee
+++ b/src/grammar.coffee
@@ -394,7 +394,7 @@ grammar: {
   # Switch/When blocks.
   Switch: [
     o "SWITCH Expression INDENT Whens OUTDENT", -> $4.rewrite_condition($2)
-    o "SWITCH Expression INDENT Whens ELSE Block OUTDENT", -> $4.rewrite_condition($2).add_else($6)
+    o "SWITCH Expression INDENT Whens ELSE Block OUTDENT", -> $4.rewrite_condition($2).add_else($6, true)
   ]
 
   # The inner list of whens.
diff --git a/src/nodes.coffee b/src/nodes.coffee
index bcd7ecd8..d47a4e9e 100644
--- a/src/nodes.coffee
+++ b/src/nodes.coffee
@@ -985,9 +985,12 @@ IfNode: exports.IfNode: inherit Node, {
     this
 
   # Rewrite a chain of IfNodes to add a default case as the final else.
-  add_else: (exprs) ->
-    if @is_chain() then @else_body.add_else(exprs) else @else_body: exprs and exprs.unwrap()
-    @children.push(exprs)
+  add_else: (exprs, statement) ->
+    if @is_chain()
+      @else_body.add_else exprs
+    else
+      exprs: exprs.unwrap() unless statement
+      @children.push @else_body: exprs
     this
 
   # If the else_body is an IfNode itself, then we've got an if-else chain.
diff --git a/test/test_switch.coffee b/test/test_switch.coffee
index 7f2fc000..549a1ddc 100644
--- a/test/test_switch.coffee
+++ b/test/test_switch.coffee
@@ -41,3 +41,13 @@ result: switch num += 5
 
 ok result
 
+
+# Ensure that trailing switch elses don't get rewritten.
+result: false
+switch "word"
+  when "one thing"
+    do_something()
+  else
+    result: true unless false
+
+ok result