Enable frozen_string_literal pragma if possible

Close #862

lib/haml.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'haml/version'
 
 # The module that contains everything Haml-related:

lib/haml/attribute_compiler.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'haml/attribute_parser'
 
 module Haml

lib/haml/attribute_parser.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 begin
   require 'ripper'
 rescue LoadError

lib/haml/buffer.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   # This class is used only internally. It holds the buffer of HTML that
   # is eventually output as the resulting document.

lib/haml/compiler.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require 'haml/attribute_builder'
 require 'haml/attribute_compiler'
 require 'haml/temple_line_counter'

lib/haml/engine.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require 'forwardable'
 
 require 'haml/parser'

lib/haml/error.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   # An exception raised by Haml code.
   class Error < StandardError

lib/haml/escapable.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   # Like Temple::Filters::Escapable, but with support for escaping by
   # Haml::Herlpers.html_escape and Haml::Herlpers.escape_once.

lib/haml/exec.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'optparse'
 require 'rbconfig'
 require 'pp'

lib/haml/filters.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "tilt"
 
 module Haml

lib/haml/generator.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   # Ruby code generator, which is a limited version of Temple::Generator.
   # Limit methods since Haml doesn't need most of them.

lib/haml/helpers.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require 'erb'
 
 module Haml

lib/haml/helpers/action_view_extensions.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   module Helpers
     @@action_view_defined = true

lib/haml/helpers/action_view_mods.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   module Helpers
     module ActionViewMods

lib/haml/helpers/action_view_xss_mods.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActionView
   module Helpers
     module CaptureHelper

lib/haml/helpers/safe_erubi_template.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'action_view'
 
 module Haml

lib/haml/helpers/safe_erubis_template.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'action_view'
 
 module Haml
@@ -28,4 +29,4 @@ module Haml
       [super, '@output_buffer.to_s'].join("\n")
     end
   end
-end
+end

lib/haml/helpers/xss_mods.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   module Helpers
     # This module overrides Haml helpers to work properly

lib/haml/options.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   # This class encapsulates all of the configuration options that Haml
   # understands. Please see the {file:REFERENCE.md#options Haml Reference} to

lib/haml/parser.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require 'strscan'
 
 module Haml

lib/haml/plugin.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
 
   # This module makes Haml work with Rails using the template handler API.

lib/haml/railtie.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'haml/template/options'
 
 # check for a compatible Rails version when Haml is loaded

lib/haml/sass_rails_filter.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   module Filters
     # This is an extension of Sass::Rails's SassTemplate class that allows

lib/haml/template.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'haml/template/options'
 if defined?(ActiveSupport)
   ActiveSupport.on_load(:action_view) do

lib/haml/template/options.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 # We keep options in its own self-contained file
 # so that we can load it independently in Rails 3,
 # where the full template stuff is lazy-loaded.

lib/haml/temple_engine.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require 'temple'
 require 'haml/escapable'
 require 'haml/generator'

lib/haml/temple_line_counter.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   # A module to count lines of expected code. This would be faster than actual code generation
   # and counting newlines in it.

lib/haml/util.rb

@@ -1,4 +1,4 @@
-# encoding: utf-8
+# frozen_string_literal: false
 
 begin
   require 'erubis/tiny'

lib/haml/version.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Haml
   VERSION = "5.0.0.beta.2"
 end