From ead9b1041c55a9d2518ab6ec2d6d30b028c74efa Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas <jashkenas@gmail.com>
Date: Sat, 14 Aug 2010 11:29:10 -0400
Subject: [PATCH] tweaking existential compilation.

---
 lib/nodes.js               | 18 ++----------------
 src/nodes.coffee           | 16 +++++-----------
 test/test_existence.coffee |  5 +++++
 3 files changed, 12 insertions(+), 27 deletions(-)

diff --git a/lib/nodes.js b/lib/nodes.js
index 007a8c9a..61f5ec65 100644
--- a/lib/nodes.js
+++ b/lib/nodes.js
@@ -322,7 +322,6 @@
       return this;
     };
     __extends(ValueNode, BaseNode);
-    ValueNode.prototype.SOAK = " == undefined ? undefined : ";
     ValueNode.prototype["class"] = 'ValueNode';
     ValueNode.prototype.children = ['base', 'properties'];
     ValueNode.prototype.push = function(prop) {
@@ -353,17 +352,6 @@
     ValueNode.prototype.isNumber = function() {
       return this.base instanceof LiteralNode && this.base.value.match(NUMBER);
     };
-    ValueNode.prototype.isStart = function(o) {
-      var node;
-      if (this === o.chainRoot && this.properties[0] instanceof AccessorNode) {
-        return true;
-      }
-      node = o.chainRoot.base || o.chainRoot.variable;
-      while (node instanceof CallNode) {
-        node = node.variable;
-      }
-      return node === this;
-    };
     ValueNode.prototype.cacheIndexes = function(o) {
       var _b, _c, _d, copy, i;
       copy = new ValueNode(this.base, this.properties.slice(0));
@@ -414,10 +402,8 @@
               temp = o.scope.freeVariable();
               complete = ("(" + (baseline = temp) + " = (" + (complete) + "))");
             }
-            if (i === 0 && this.isStart(o)) {
-              complete = ("typeof " + (complete) + " === \"undefined\" || " + (baseline));
-            }
-            return complete += this.SOAK + (baseline += prop.compile(o));
+            complete = i === 0 ? ("(typeof " + (complete) + " === \"undefined\" || " + (baseline) + " === null) ? undefined : ") : ("" + (complete) + " == undefined ? undefined : ");
+            return complete += (baseline += prop.compile(o));
           } else {
             part = prop.compile(o);
             baseline += part;
diff --git a/src/nodes.coffee b/src/nodes.coffee
index 29bb40c2..deba0ee9 100644
--- a/src/nodes.coffee
+++ b/src/nodes.coffee
@@ -288,8 +288,6 @@ exports.ReturnNode = class ReturnNode extends BaseNode
 # or vanilla.
 exports.ValueNode = class ValueNode extends BaseNode
 
-  SOAK:     " == undefined ? undefined : "
-
   class:     'ValueNode'
   children: ['base', 'properties']
 
@@ -331,13 +329,6 @@ exports.ValueNode = class ValueNode extends BaseNode
   isNumber: ->
     @base instanceof LiteralNode and @base.value.match NUMBER
 
-  # Works out if the value is the start of a chain.
-  isStart: (o) ->
-    return true if this is o.chainRoot and @properties[0] instanceof AccessorNode
-    node = o.chainRoot.base or o.chainRoot.variable
-    while node instanceof CallNode then node = node.variable
-    node is this
-
   # If the value node has indexes containing function calls, and the value node
   # needs to be used twice, in compound assignment ... then we need to cache
   # the value of the indexes.
@@ -373,8 +364,11 @@ exports.ValueNode = class ValueNode extends BaseNode
         if @base instanceof CallNode or @base.contains((n) -> n instanceof CallNode) and i is 0
           temp = o.scope.freeVariable()
           complete = "(#{ baseline = temp } = (#{complete}))"
-        complete = "typeof #{complete} === \"undefined\" || #{baseline}" if i is 0 and @isStart(o)
-        complete += @SOAK + (baseline += prop.compile(o))
+        complete = if i is 0
+          "(typeof #{complete} === \"undefined\" || #{baseline} === null) ? undefined : "
+        else
+          "#{complete} == undefined ? undefined : "
+        complete += (baseline += prop.compile(o))
       else
         part = prop.compile(o)
         baseline += part
diff --git a/test/test_existence.coffee b/test/test_existence.coffee
index 85c1cf86..c54d7f5e 100644
--- a/test/test_existence.coffee
+++ b/test/test_existence.coffee
@@ -70,6 +70,11 @@ result = value?.toString().toLowerCase()
 ok result is '10'
 
 
+# Soaks inner values.
+ident = (obj) -> obj
+ok ident(non?.existent().method()) is undefined
+
+
 # Soaks constructor invocations.
 a = 0
 class Foo