Use the file's first line to determine the grammar.

Only when it cannot be determined by the file's extension fails. Fixes #75

spec/app/text-mate-bundle-spec.coffee

@@ -21,3 +21,18 @@ describe "TextMateBundle", ->
       spyOn(console, 'warn')
       expect(-> new TextMateBundle(bundlePath)).not.toThrow()
       expect(console.warn).toHaveBeenCalled()
+
+  describe ".grammarForFilePath(filePath)", ->
+    it "uses the filePath's extension to load the correct grammar", ->
+      expect(TextMateBundle.grammarForFilePath("file.js").name).toBe "JavaScript"
+
+    it "uses the filePath's base name if there is no extension", ->
+      expect(TextMateBundle.grammarForFilePath("Rakefile").name).toBe "Ruby"
+
+    it "uses the filePath's shebang line if the grammar cannot be determined by the extension or basename", ->
+      filePath = require.resolve("fixtures/shebang")
+      expect(TextMateBundle.grammarForFilePath(filePath).name).toBe "Ruby"
+
+    it "uses plain text if no grammar can be found", ->
+      filePath = require.resolve("this-is-not-a-real-file")
+      expect(TextMateBundle.grammarForFilePath(filePath).name).toBe "Plain Text"

spec/fixtures/shebang

@@ -0,0 +1,3 @@
+#!/usr/bin/ruby
+
+puts "America – fuck yeah!"

src/app/text-mate-bundle.coffee

@@ -10,6 +10,7 @@ class TextMateBundle
   @grammarsByScopeName: {}
   @preferencesByScopeSelector: {}
   @bundles: []
+  @grammars: []
 
   @loadAll: ->
     globalBundles = fs.list(require.resolve("bundles"))
@@ -27,6 +28,7 @@ class TextMateBundle
       @preferencesByScopeSelector[scopeSelector] = preferences
 
     for grammar in bundle.grammars
+      @grammars.push(grammar)
       for fileType in grammar.fileTypes
         @grammarsByFileType[fileType] = grammar
         @grammarsByScopeName[grammar.scopeName] = grammar
@@ -36,7 +38,15 @@ class TextMateBundle
     if filePath and extension.length == 0
       extension = fs.base(filePath)
 
-    @grammarsByFileType[extension] or @grammarsByFileType["txt"]
+    @grammarsByFileType[extension] or @grammarByShebang(filePath) or @grammarsByFileType["txt"]
+
+  @grammarByShebang: (filePath) ->
+    try
+      firstLine = fs.read(filePath).match(/.*/)[0]
+    catch e
+      null
+
+    _.find @grammars, (grammar) -> grammar.firstLineRegex?.test(firstLine)
 
   @grammarForScopeName: (scopeName) ->
     @grammarsByScopeName[scopeName]

src/app/text-mate-grammar.coffee

@@ -16,10 +16,12 @@ class TextMateGrammar
   scopeName: null
   repository: null
   initialRule: null
+  firstLineRegex: null
 
-  constructor: ({ @name, @fileTypes, @scopeName, patterns, repository, @foldingStopMarker}) ->
+  constructor: ({ @name, @fileTypes, @scopeName, patterns, repository, @foldingStopMarker, firstLineMatch}) ->
     @initialRule = new Rule(this, {@scopeName, patterns})
     @repository = {}
+    @firstLineRegex = new OnigRegExp(firstLineMatch) if firstLineMatch
 
     for name, data of repository
       @repository[name] = new Rule(this, data)