CoffeeScript JS guessing

lib/linguist/blob_helper.rb

@@ -150,6 +150,8 @@ module Linguist
     # Generated source code is supressed in diffs and is ignored by
     # langauge statistics.
     #
+    # Requires Blob#data
+    #
     # Includes:
     # - XCode project XML files
     # - Minified JavaScript
@@ -158,6 +160,8 @@ module Linguist
     def generated?
       if ['.xib', '.nib', '.pbxproj'].include?(pathname.extname)
         true
+      elsif generated_coffeescript?
+        true
       elsif pathname.extname == '.js'
         # JS is minified if any lines are longer than 1000c
         lines.any? { |l| l.length > 1000 }
@@ -166,6 +170,42 @@ module Linguist
       end
     end
 
+    # Internal: Is the blob JS generated by CoffeeScript?
+    #
+    # Requires Blob#data
+    #
+    # CoffeScript is meant to output JS that would be difficult to
+    # tell if it was generated or not. Look for a number of patterns
+    # outputed by the CS compiler.
+    #
+    # Return true or false
+    def generated_coffeescript?
+      return unless pathname.extname == '.js'
+
+      if lines[0] == '(function() {' &&     # First line is module closure opening
+          lines[-2] == '}).call(this);' &&  # Second to last line closes module closure
+          lines[-1] == ''                   # Last line is blank
+
+        score = 0
+
+        lines.each do |line|
+          if line =~ /var /
+            # Underscored temp vars are likely to be Coffee
+            score += 1 * line.gsub(/(_fn|_i|_len|_ref|_results)/).count
+
+            # bind and extend functions are very Coffee specific
+            score += 3 * line.gsub(/(__bind|__extends|__hasProp|__indexOf|__slice)/).count
+          end
+        end
+
+        # Require a score of 3. This is fairly arbitrary. Consider
+        # tweaking later.
+        score >= 3
+      else
+        false
+      end
+    end
+
     # Public: Should the blob be indexed for searching?
     #
     # Excluded:

test/fixtures/blob/coffee/classes.coffee

@@ -0,0 +1,21 @@
+class Animal
+  constructor: (@name) ->
+
+  move: (meters) ->
+    alert @name + " moved " + meters + "m."
+
+class Snake extends Animal
+  move: ->
+    alert "Slithering..."
+    super 5
+
+class Horse extends Animal
+  move: ->
+    alert "Galloping..."
+    super 45
+
+sam = new Snake "Sammy the Python"
+tom = new Horse "Tommy the Palomino"
+
+sam.move()
+tom.move()

test/fixtures/blob/coffee/classes.js

@@ -0,0 +1,46 @@
+(function() {
+  var Animal, Horse, Snake, sam, tom;
+  var __hasProp = Object.prototype.hasOwnProperty, __extends = function(child, parent) {
+    for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; }
+    function ctor() { this.constructor = child; }
+    ctor.prototype = parent.prototype;
+    child.prototype = new ctor;
+    child.__super__ = parent.prototype;
+    return child;
+  };
+  Animal = (function() {
+    function Animal(name) {
+      this.name = name;
+    }
+    Animal.prototype.move = function(meters) {
+      return alert(this.name + " moved " + meters + "m.");
+    };
+    return Animal;
+  })();
+  Snake = (function() {
+    __extends(Snake, Animal);
+    function Snake() {
+      Snake.__super__.constructor.apply(this, arguments);
+    }
+    Snake.prototype.move = function() {
+      alert("Slithering...");
+      return Snake.__super__.move.call(this, 5);
+    };
+    return Snake;
+  })();
+  Horse = (function() {
+    __extends(Horse, Animal);
+    function Horse() {
+      Horse.__super__.constructor.apply(this, arguments);
+    }
+    Horse.prototype.move = function() {
+      alert("Galloping...");
+      return Horse.__super__.move.call(this, 45);
+    };
+    return Horse;
+  })();
+  sam = new Snake("Sammy the Python");
+  tom = new Horse("Tommy the Palomino");
+  sam.move();
+  tom.move();
+}).call(this);

test/fixtures/blob/coffee/empty.js

@@ -0,0 +1,3 @@
+(function() {
+
+}).call(this);

test/fixtures/blob/coffee/hello.coffee

@@ -0,0 +1 @@
+console.log "Hello, World!"

test/fixtures/blob/coffee/hello.js

@@ -0,0 +1,3 @@
+(function() {
+  console.log("Hello, World!");
+}).call(this);

test/fixtures/blob/coffee/intro.coffee

@@ -0,0 +1,28 @@
+# Assignment:
+number   = 42
+opposite = true
+
+# Conditions:
+number = -42 if opposite
+
+# Functions:
+square = (x) -> x * x
+
+# Arrays:
+list = [1, 2, 3, 4, 5]
+
+# Objects:
+math =
+  root:   Math.sqrt
+  square: square
+  cube:   (x) -> x * square x
+
+# Splats:
+race = (winner, runners...) ->
+  print winner, runners
+
+# Existence:
+alert "I knew it!" if elvis?
+
+# Array comprehensions:
+cubes = (math.cube num for num in list)

test/fixtures/blob/coffee/intro.js

@@ -0,0 +1,37 @@
+(function() {
+  var cubes, list, math, num, number, opposite, race, square;
+  var __slice = Array.prototype.slice;
+  number = 42;
+  opposite = true;
+  if (opposite) {
+    number = -42;
+  }
+  square = function(x) {
+    return x * x;
+  };
+  list = [1, 2, 3, 4, 5];
+  math = {
+    root: Math.sqrt,
+    square: square,
+    cube: function(x) {
+      return x * square(x);
+    }
+  };
+  race = function() {
+    var runners, winner;
+    winner = arguments[0], runners = 2 <= arguments.length ? __slice.call(arguments, 1) : [];
+    return print(winner, runners);
+  };
+  if (typeof elvis !== "undefined" && elvis !== null) {
+    alert("I knew it!");
+  }
+  cubes = (function() {
+    var _i, _len, _results;
+    _results = [];
+    for (_i = 0, _len = list.length; _i < _len; _i++) {
+      num = list[_i];
+      _results.push(math.cube(num));
+    }
+    return _results;
+  })();
+}).call(this);

test/test_blob.rb

@@ -116,6 +116,15 @@ class TestBlob < Test::Unit::TestCase
     # Minified JS
     assert !blob("jquery-1.6.1.js").generated?
     assert blob("jquery-1.6.1.min.js").generated?
+
+    # CoffeScript JS
+
+    # These examples are to basic to tell
+    assert !blob("coffee/empty.js").generated?
+    assert !blob("coffee/hello.js").generated?
+
+    assert blob("coffee/intro.js").generated?
+    assert blob("coffee/classes.js").generated?
   end
 
   def test_vendored