Add Lexer class

lib/linguist/lexer.rb

@@ -0,0 +1,39 @@
+require 'yaml'
+
+module Linguist
+  class Lexer < Struct.new(:name, :aliases, :filenames, :mimetypes)
+    @name_index  = {}
+    @alias_index = {}
+
+    def self.find_by_name(name)
+      @name_index[name.downcase]
+    end
+
+    def self.find_by_alias(name)
+      @alias_index[name.downcase]
+    end
+
+    def self.[](name)
+      find_by_name(name) || find_by_alias(name)
+    end
+
+    def to_s
+      aliases.first
+    end
+
+    def ==(other)
+      eql?(other)
+    end
+
+    def eql?(other)
+      equal?(other)
+    end
+
+    YAML.load_file(File.expand_path("../lexers.yml", __FILE__)).each do |lexer|
+      @name_index[lexer.name.downcase] = lexer
+      lexer.aliases.each do |name|
+        @alias_index[name.downcase] = lexer
+      end
+    end
+  end
+end