From f76bab512f8094e157cf283d8d689f57b2af74ee Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Sun, 23 Dec 2012 13:19:20 -0700
Subject: [PATCH] Most recently added scoped properties win in case of a
 specificity tie

This makes the scoped property system mimic the behavior of CSS. When
there is a tie, the scoped properties loaded later in the cascade win.
I also optimize the scanning of all the properties, checking only those
sets of properties that have a value for the desired key path, to reduce
the need to match a ton of scope selectors.
---
 spec/app/syntax-spec.coffee |  7 ++++++
 src/app/syntax.coffee       | 46 ++++++++++++++++++++++---------------
 2 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/spec/app/syntax-spec.coffee b/spec/app/syntax-spec.coffee
index 722d6db91..c3117fb46 100644
--- a/spec/app/syntax-spec.coffee
+++ b/spec/app/syntax-spec.coffee
@@ -10,3 +10,10 @@ describe "the `syntax` global", ->
       expect(syntax.getProperty([".source.js", ".string.quoted.double.js"], "foo.bar.baz")).toBe 22
       expect(syntax.getProperty([".source.js", ".variable.assignment.js"], "foo.bar.baz")).toBe 11
       expect(syntax.getProperty([".text"], "foo.bar.baz")).toBe 1
+
+    it "favors the most recently added properties in the event of a specificity tie", ->
+      syntax.addProperties(".source.coffee .string.quoted.single", foo: bar: baz: 42)
+      syntax.addProperties(".source.coffee .string.quoted.double", foo: bar: baz: 22)
+
+      expect(syntax.getProperty([".source.coffee", ".string.quoted.single"], "foo.bar.baz")).toBe 42
+      expect(syntax.getProperty([".source.coffee", ".string.quoted.single.double"], "foo.bar.baz")).toBe 22
diff --git a/src/app/syntax.coffee b/src/app/syntax.coffee
index bccf22e3c..f54b3f3da 100644
--- a/src/app/syntax.coffee
+++ b/src/app/syntax.coffee
@@ -7,38 +7,48 @@ module.exports =
 class Syntax
   constructor: ->
     @globalProperties = {}
+    @scopedPropertiesIndex = 0
+    @scopedProperties = []
     @propertiesBySelector = {}
 
   addProperties: (args...) ->
-    scopeSelector = args.shift() if args.length > 1
+    selector = args.shift() if args.length > 1
     properties = args.shift()
 
-    if scopeSelector
-      @propertiesBySelector[scopeSelector] ?= {}
-      _.extend(@propertiesBySelector[scopeSelector], properties)
+    if selector
+      @scopedProperties.unshift(
+        selector: selector,
+        properties: properties,
+        specificity: Specificity(selector),
+        index: @scopedPropertiesIndex++
+      )
     else
       _.extend(@globalProperties, properties)
 
   getProperty: (scope, keyPath) ->
-    for object in @propertiesForScope(scope)
+    for object in @propertiesForScope(scope, keyPath)
       value = _.valueForKeyPath(object, keyPath)
       return value if value?
     undefined
 
-  propertiesForScope: (scope) ->
-    matchingSelectors = []
-    element = @buildScopeElement(scope)
-    while element
-      matchingSelectors.push(@matchingSelectorsForElement(element)...)
-      element = element.parentNode
-    properties = matchingSelectors.map (selector) => @propertiesBySelector[selector]
-    properties.concat([@globalProperties])
+  propertiesForScope: (scope, keyPath) ->
+    matchingProperties = []
+    candidates = @scopedProperties.filter ({properties}) -> _.valueForKeyPath(properties, keyPath)?
+    if candidates.length
+      element = @buildScopeElement(scope)
+      while element
+        matchingProperties.push(@matchingPropertiesForElement(element, candidates)...)
+        element = element.parentNode
+    matchingProperties.concat([@globalProperties])
 
-  matchingSelectorsForElement: (element) ->
-    matchingSelectors = []
-    for selector of @propertiesBySelector
-      matchingSelectors.push(selector) if jQuery.find.matchesSelector(element, selector)
-    matchingSelectors.sort (a, b) -> Specificity(b) - Specificity(a)
+  matchingPropertiesForElement: (element, candidates) ->
+    matchingScopedProperties = candidates.filter ({selector}) -> jQuery.find.matchesSelector(element, selector)
+    matchingScopedProperties.sort (a, b) ->
+      if a.specificity == b.specificity
+        b.index - a.index
+      else
+        b.specificity - a.specificity
+    _.pluck matchingScopedProperties, 'properties'
 
   buildScopeElement: (scope) ->
     scope = new Array(scope...)