# = ERB -- Ruby Templating
#
# Author:: Masatoshi SEKI
# Documentation:: James Edward Gray II, Gavin Sinclair, and Simon Chiang
#
# See ERB for primary documentation and ERB::Util for a couple of utility
# routines.
#
# Copyright (c) 1999-2000,2002,2003 Masatoshi SEKI
#
# You can redistribute it and/or modify it under the same terms as Ruby.

#
# = ERB -- Ruby Templating
#
# == Introduction
#
# ERB provides an easy to use but powerful templating system for Ruby.  Using
# ERB, actual Ruby code can be added to any plain text document for the
# purposes of generating document information details and/or flow control.
#
# A very simple example is this:
#
#   require 'erb'
#
#   x = 42
#   template = ERB.new <<-EOF
#     The value of x is: <%= x %>
#   EOF
#   puts template.result(binding)
#
# <em>Prints:</em> The value of x is: 42
#
# More complex examples are given below.
#
#
# == Recognized Tags
#
# ERB recognizes certain tags in the provided template and converts them based
# on the rules below:
#
#   <% Ruby code -- inline with output %>
#   <%= Ruby expression -- replace with result %>
#   <%# comment -- ignored -- useful in testing %>
#   % a line of Ruby code -- treated as <% line %> (optional -- see ERB.new)
#   %% replaced with % if first thing on a line and % processing is used
#   <%% or %%> -- replace with <% or %> respectively
#
# All other text is passed through ERB filtering unchanged.
#
#
# == Options
#
# There are several settings you can change when you use ERB:
# * the nature of the tags that are recognized;
# * the value of <tt>$SAFE</tt> under which the template is run;
# * the binding used to resolve local variables in the template.
#
# See the ERB.new and ERB#result methods for more detail.
#
# == Character encodings
#
# ERB (or ruby code generated by ERB) returns a string in the same
# character encoding as the input string.  When the input string has
# a magic comment, however, it returns a string in the encoding specified
# by the magic comment.
#
#   # -*- coding: UTF-8 -*-
#   require 'erb'
#
#   template = ERB.new <<EOF
#   <%#-*- coding: Big5 -*-%>
#     \_\_ENCODING\_\_ is <%= \_\_ENCODING\_\_ %>.
#   EOF
#   puts template.result
#
# <em>Prints:</em> \_\_ENCODING\_\_ is Big5.
#
#
# == Examples
#
# === Plain Text
#
# ERB is useful for any generic templating situation.  Note that in this example, we use the
# convenient "% at start of line" tag, and we quote the template literally with
# <tt>%q{...}</tt> to avoid trouble with the backslash.
#
#   require "erb"
#
#   # Create template.
#   template = %q{
#     From:  James Edward Gray II <james@grayproductions.net>
#     To:  <%= to %>
#     Subject:  Addressing Needs
#
#     <%= to[/\w+/] %>:
#
#     Just wanted to send a quick note assuring that your needs are being
#     addressed.
#
#     I want you to know that my team will keep working on the issues,
#     especially:
#
#     <%# ignore numerous minor requests -- focus on priorities %>
#     % priorities.each do |priority|
#       * <%= priority %>
#     % end
#
#     Thanks for your patience.
#
#     James Edward Gray II
#   }.gsub(/^  /, '')
#
#   message = ERB.new(template, 0, "%<>")
#
#   # Set up template data.
#   to = "Community Spokesman <spokesman@ruby_community.org>"
#   priorities = [ "Run Ruby Quiz",
#                  "Document Modules",
#                  "Answer Questions on Ruby Talk" ]
#
#   # Produce result.
#   email = message.result
#   puts email
#
# <i>Generates:</i>
#
#   From:  James Edward Gray II <james@grayproductions.net>
#   To:  Community Spokesman <spokesman@ruby_community.org>
#   Subject:  Addressing Needs
#
#   Community:
#
#   Just wanted to send a quick note assuring that your needs are being addressed.
#
#   I want you to know that my team will keep working on the issues, especially:
#
#       * Run Ruby Quiz
#       * Document Modules
#       * Answer Questions on Ruby Talk
#
#   Thanks for your patience.
#
#   James Edward Gray II
#
# === Ruby in HTML
#
# ERB is often used in <tt>.rhtml</tt> files (HTML with embedded Ruby).  Notice the need in
# this example to provide a special binding when the template is run, so that the instance
# variables in the Product object can be resolved.
#
#   require "erb"
#
#   # Build template data class.
#   class Product
#     def initialize( code, name, desc, cost )
#       @code = code
#       @name = name
#       @desc = desc
#       @cost = cost
#
#       @features = [ ]
#     end
#
#     def add_feature( feature )
#       @features << feature
#     end
#
#     # Support templating of member data.
#     def get_binding
#       binding
#     end
#
#     # ...
#   end
#
#   # Create template.
#   template = %{
#     <html>
#       <head><title>Ruby Toys -- <%= @name %></title></head>
#       <body>
#
#         <h1><%= @name %> (<%= @code %>)</h1>
#         <p><%= @desc %></p>
#
#         <ul>
#           <% @features.each do |f| %>
#             <li><b><%= f %></b></li>
#           <% end %>
#         </ul>
#
#         <p>
#           <% if @cost < 10 %>
#             <b>Only <%= @cost %>!!!</b>
#           <% else %>
#              Call for a price, today!
#           <% end %>
#         </p>
#
#       </body>
#     </html>
#   }.gsub(/^  /, '')
#
#   rhtml = ERB.new(template)
#
#   # Set up template data.
#   toy = Product.new( "TZ-1002",
#                      "Rubysapien",
#                      "Geek's Best Friend!  Responds to Ruby commands...",
#                      999.95 )
#   toy.add_feature("Listens for verbal commands in the Ruby language!")
#   toy.add_feature("Ignores Perl, Java, and all C variants.")
#   toy.add_feature("Karate-Chop Action!!!")
#   toy.add_feature("Matz signature on left leg.")
#   toy.add_feature("Gem studded eyes... Rubies, of course!")
#
#   # Produce result.
#   rhtml.run(toy.get_binding)
#
# <i>Generates (some blank lines removed):</i>
#
#    <html>
#      <head><title>Ruby Toys -- Rubysapien</title></head>
#      <body>
#
#        <h1>Rubysapien (TZ-1002)</h1>
#        <p>Geek's Best Friend!  Responds to Ruby commands...</p>
#
#        <ul>
#            <li><b>Listens for verbal commands in the Ruby language!</b></li>
#            <li><b>Ignores Perl, Java, and all C variants.</b></li>
#            <li><b>Karate-Chop Action!!!</b></li>
#            <li><b>Matz signature on left leg.</b></li>
#            <li><b>Gem studded eyes... Rubies, of course!</b></li>
#        </ul>
#
#        <p>
#             Call for a price, today!
#        </p>
#
#      </body>
#    </html>
#
#
# == Notes
#
# There are a variety of templating solutions available in various Ruby projects:
# * ERB's big brother, eRuby, works the same but is written in C for speed;
# * Amrita (smart at producing HTML/XML);
# * cs/Template (written in C for speed);
# * RDoc, distributed with Ruby, uses its own template engine, which can be reused elsewhere;
# * and others; search the RAA.
#
# Rails, the web application framework, uses ERB to create views.
#
class ERB
  Revision = '$Date::                           $'      #'

  # Returns revision information for the erb.rb module.
  def self.version
    "erb.rb [2.1.0 #{ERB::Revision.split[1]}]"
  end
end

#--
# ERB::Compiler
class ERB
  # = ERB::Compiler
  #
  # Compiles ERB templates into Ruby code; the compiled code produces the
  # template result when evaluated. ERB::Compiler provides hooks to define how
  # generated output is handled.
  #
  # Internally ERB does something like this to generate the code returned by
  # ERB#src:
  #
  #   compiler = ERB::Compiler.new('<>')
  #   compiler.pre_cmd    = ["_erbout=''"]
  #   compiler.put_cmd    = "_erbout.concat"
  #   compiler.insert_cmd = "_erbout.concat"
  #   compiler.post_cmd   = ["_erbout"]
  #
  #   code, enc = compiler.compile("Got <%= obj %>!\n")
  #   puts code
  #
  # <i>Generates</i>:
  #
  #   #coding:UTF-8
  #   _erbout=''; _erbout.concat "Got "; _erbout.concat(( obj ).to_s); _erbout.concat "!\n"; _erbout
  #
  # By default the output is sent to the print method.  For example:
  #
  #   compiler = ERB::Compiler.new('<>')
  #   code, enc = compiler.compile("Got <%= obj %>!\n")
  #   puts code
  #
  # <i>Generates</i>:
  #
  #   #coding:UTF-8
  #   print "Got "; print(( obj ).to_s); print "!\n"
  #
  # == Evaluation
  #
  # The compiled code can be used in any context where the names in the code
  # correctly resolve. Using the last example, each of these print 'Got It!'
  #
  # Evaluate using a variable:
  #
  #   obj = 'It'
  #   eval code
  #
  # Evaluate using an input:
  #
  #   mod = Module.new
  #   mod.module_eval %{
  #     def get(obj)
  #       #{code}
  #     end
  #   }
  #   extend mod
  #   get('It')
  #
  # Evaluate using an accessor:
  #
  #   klass = Class.new Object
  #   klass.class_eval %{
  #     attr_accessor :obj
  #     def initialize(obj)
  #       @obj = obj
  #     end
  #     def get_it
  #       #{code}
  #     end
  #   }
  #   klass.new('It').get_it
  #
  # Good! See also ERB#def_method, ERB#def_module, and ERB#def_class.
  class Compiler # :nodoc:
    class PercentLine # :nodoc:
      def initialize(str)
        @value = str
      end
      attr_reader :value
      alias :to_s :value