prefer to load from languages.json if it exists

Rakefile

@@ -1,5 +1,7 @@
 require 'rake/clean'
 require 'rake/testtask'
+require 'yaml'
+require 'json'
 
 task :default => :test
 
@@ -13,6 +15,13 @@ task :samples do
   File.open('lib/linguist/samples.json', 'w') { |io| io.write json }
 end
 
+task :build_gem do
+  languages = YAML.load_file("lib/linguist/languages.yml")
+  File.write("lib/linguist/languages.json", JSON.dump(languages))
+  `gem build github-linguist.gemspec`
+  File.delete("lib/linguist/languages.json")
+end
+
 namespace :classifier do
   LIMIT = 1_000
 

lib/linguist/language.rb

@@ -1,6 +1,10 @@
 require 'escape_utils'
 require 'pygments'
 require 'yaml'
+begin
+  require 'json'
+rescue LoadError
+end
 
 require 'linguist/classifier'
 require 'linguist/samples'
@@ -455,7 +459,16 @@ module Linguist
   filenames = Samples::DATA['filenames']
   popular = YAML.load_file(File.expand_path("../popular.yml", __FILE__))
 
-  YAML.load_file(File.expand_path("../languages.yml", __FILE__)).each do |name, options|
+  languages_yml = File.expand_path("../languages.yml", __FILE__)
+  languages_json = File.expand_path("../languages.json", __FILE__)
+
+  if File.exist?(languages_json) && defined?(JSON)
+    languages = JSON.load(File.read(languages_json))
+  else
+    languages = YAML.load_file(languages_yml)
+  end
+
+  languages.each do |name, options|
     options['extensions'] ||= []
     options['filenames'] ||= []