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✏️ Editing: erb.rb

# -*- coding: us-ascii -*-
# frozen_string_literal: true
# = 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.

require "cgi/util"

#
# = 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)
#
# Prints: 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
#
# Prints: \_\_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
#
# Generates:
#
# 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>
# <%= @desc %>
#
# <ul>
# <% @features.each do |f| %>
# <li><%= f %></li>
# <% end %>
# </ul>
#
# 
# <% if @cost < 10 %>
# Only <%= @cost %>!!!
# <% else %>
# Call for a price, today!
# <% end %>
# 
#
# </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)
#
# Generates (some blank lines removed):
#
# <html>
# <head><title>Ruby Toys -- Rubysapien</title></head>
# <body>
#
# <h1>Rubysapien (TZ-1002)</h1>
# Geek's Best Friend! Responds to Ruby commands...
#
# <ul>
# <li>Listens for verbal commands in the Ruby language!</li>
# <li>Ignores Perl, Java, and all C variants.</li>
# <li>Karate-Chop Action!!!</li>
# <li>Matz signature on left leg.</li>
# <li>Gem studded eyes... Rubies, of course!</li>
# </ul>
#
# 
# Call for a price, today!
# 
#
# </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 {RubyGems.org}[https://rubygems.org/] or
# {The Ruby Toolbox}[https://www.ruby-toolbox.com/].
#
# Rails, the web application framework, uses ERB to create views.
#
class ERB
 Revision = '$Date:: 2018-01-03 18:11:47 +0000#$' # :nodoc: #'

# 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.<<"
 # compiler.insert_cmd = "_erbout.<<"
 # compiler.post_cmd = ["_erbout"]
 #
 # code, enc = compiler.compile("Got <%= obj %>!\n")
 # puts code
 #
 # Generates:
 #
 # #coding:UTF-8
 # _erbout=+''; _erbout.<< "Got ".freeze; _erbout.<<(( obj ).to_s); _erbout.<< "!\n".freeze; _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
 #
 # Generates:
 #
 # #coding:UTF-8
 # print "Got ".freeze; print(( obj ).to_s); print "!\n".freeze
 #
 # == 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
 end

class Scanner # :nodoc:
 @scanner_map = {}
 class << self
 def register_scanner(klass, trim_mode, percent)
 @scanner_map[[trim_mode, percent]] = klass
 end
 alias :regist_scanner :register_scanner
 end

def self.default_scanner=(klass)
        @default_scanner = klass
      end

def self.make_scanner(src, trim_mode, percent)
        klass = @scanner_map.fetch([trim_mode, percent], @default_scanner)
        klass.new(src, trim_mode, percent)
      end

DEFAULT_STAGS = %w(<%% <%= <%# <%).freeze
 DEFAULT_ETAGS = %w(%%> %>).freeze
 def initialize(src, trim_mode, percent)
 @src = src
 @stag = nil
 @stags = DEFAULT_STAGS
 @etags = DEFAULT_ETAGS
 end
 attr_accessor :stag
 attr_reader :stags, :etags

def scan; end
    end

class TrimScanner < Scanner # :nodoc:
 def initialize(src, trim_mode, percent)
 super
 @trim_mode = trim_mode
 @percent = percent
 if @trim_mode == '>'
 @scan_reg = /(.*?)(%>\r?\n|#{(stags + etags).join('|')}|\n|\z)/m
 @scan_line = self.method(:trim_line1)
 elsif @trim_mode == '<>'
 @scan_reg = /(.*?)(%>\r?\n|#{(stags + etags).join('|')}|\n|\z)/m
 @scan_line = self.method(:trim_line2)
 elsif @trim_mode == '-'
 @scan_reg = /(.*?)(^[ \t]*<%\-|<%\-|-%>\r?\n|-%>|#{(stags + etags).join('|')}|\z)/m
 @scan_line = self.method(:explicit_trim_line)
 else
 @scan_reg = /(.*?)(#{(stags + etags).join('|')}|\n|\z)/m
 @scan_line = self.method(:scan_line)
 end
 end

def scan(&block)
        @stag = nil
        if @percent
          @src.each_line do |line|
            percent_line(line, &block)
          end
        else
          @scan_line.call(@src, &block)
        end
        nil
      end

def percent_line(line, &block)
        if @stag || line[0] != ?%
          return @scan_line.call(line, &block)
        end

line[0] = ''
        if line[0] == ?%
          @scan_line.call(line, &block)
        else
          yield(PercentLine.new(line.chomp))
        end
      end

def scan_line(line)
        line.scan(@scan_reg) do |tokens|
          tokens.each do |token|
            next if token.empty?
            yield(token)
          end
        end
      end

def trim_line1(line)
        line.scan(@scan_reg) do |tokens|
          tokens.each do |token|
            next if token.empty?
            if token == "%>\n" || token == "%>\r\n"
              yield('%>')
              yield(:cr)
            else
              yield(token)
            end
          end
        end
      end

def trim_line2(line)
        head = nil
        line.scan(@scan_reg) do |tokens|
          tokens.each do |token|
            next if token.empty?
            head = token unless head
            if token == "%>\n" || token == "%>\r\n"
              yield('%>')
              if is_erb_stag?(head)
                yield(:cr)
              else
                yield("\n")
              end
              head = nil
            else
              yield(token)
              head = nil if token == "\n"
            end
          end
        end
      end

def explicit_trim_line(line)
 line.scan(@scan_reg) do |tokens|
 tokens.each do |token|
 next if token.empty?
 if @stag.nil? && /[ \t]*<%-/ =~ token
 yield('<%')
 elsif @stag && (token == "-%>\n" || token == "-%>\r\n")
 yield('%>')
 yield(:cr)
 elsif @stag && token == '-%>'
 yield('%>')
 else
 yield(token)
 end
 end
 end
 end

ERB_STAG = %w(<%= <%# <%)
 def is_erb_stag?(s)
 ERB_STAG.member?(s)
 end
 end

Scanner.default_scanner = TrimScanner

begin
 require 'strscan'
 rescue LoadError
 else
 class SimpleScanner < Scanner # :nodoc:
 def scan
 stag_reg = (stags == DEFAULT_STAGS) ? /(.*?)(<%[%=#]?|\z)/m : /(.*?)(#{stags.join('|')}|\z)/m
 etag_reg = (etags == DEFAULT_ETAGS) ? /(.*?)(%%?>|\z)/m : /(.*?)(#{etags.join('|')}|\z)/m
 scanner = StringScanner.new(@src)
 while ! scanner.eos?
 scanner.scan(@stag ? etag_reg : stag_reg)
 yield(scanner[1])
 yield(scanner[2])
 end
 end
 end
 Scanner.register_scanner(SimpleScanner, nil, false)

# Deprecated. Kept for backward compatibility.
      SimpleScanner2 = SimpleScanner # :nodoc:
      deprecate_constant :SimpleScanner2

class ExplicitScanner < Scanner # :nodoc:
 def scan
 stag_reg = /(.*?)(^[ \t]*<%-|<%-|#{stags.join('|')}|\z)/m
 etag_reg = /(.*?)(-%>|#{etags.join('|')}|\z)/m
 scanner = StringScanner.new(@src)
 while ! scanner.eos?
 scanner.scan(@stag ? etag_reg : stag_reg)
 yield(scanner[1])

elem = scanner[2]
 if /[ \t]*<%-/ =~ elem
 yield('<%')
 elsif elem == '-%>'
 yield('%>')
 yield(:cr) if scanner.scan(/(\r?\n|\z)/)
 else
 yield(elem)
 end
 end
 end
 end
 Scanner.register_scanner(ExplicitScanner, '-', false)
 end

class Buffer # :nodoc:
 def initialize(compiler, enc=nil, frozen=nil)
 @compiler = compiler
 @line = []
 @script = +''
 @script << "#coding:#{enc}\n" if enc
 @script << "#frozen-string-literal:#{frozen}\n" unless frozen.nil?
 @compiler.pre_cmd.each do |x|
 push(x)
 end
 end
 attr_reader :script

def push(cmd)
 @line << cmd
 end

def cr
 @script << (@line.join('; '))
 @line = []
 @script << "\n"
 end

def close
 return unless @line
 @compiler.post_cmd.each do |x|
 push(x)
 end
 @script << (@line.join('; '))
 @line = nil
 end
 end

def add_put_cmd(out, content)
      out.push("#{@put_cmd} #{content.dump}.freeze#{"\n" * content.count("\n")}")
    end

def add_insert_cmd(out, content)
      out.push("#{@insert_cmd}((#{content}).to_s)")
    end

# Compiles an ERB template into Ruby code.  Returns an array of the code
    # and encoding like ["code", Encoding].
    def compile(s)
      enc = s.encoding
      raise ArgumentError, "#{enc} is not ASCII compatible" if enc.dummy?
      s = s.b # see String#b
      magic_comment = detect_magic_comment(s, enc)
      out = Buffer.new(self, *magic_comment)

self.content = +''
      scanner = make_scanner(s)
      scanner.scan do |token|
        next if token.nil?
        next if token == ''
        if scanner.stag.nil?
          compile_stag(token, out, scanner)
        else
          compile_etag(token, out, scanner)
        end
      end
      add_put_cmd(out, content) if content.size > 0
      out.close
      return out.script, *magic_comment
    end

def compile_stag(stag, out, scanner)
 case stag
 when PercentLine
 add_put_cmd(out, content) if content.size > 0
 self.content = +''
 out.push(stag.to_s)
 out.cr
 when :cr
 out.cr
 when '<%', '<%=', '<%#'
 scanner.stag = stag
 add_put_cmd(out, content) if content.size > 0
 self.content = +''
 when "\n"
 content << "\n"
 add_put_cmd(out, content)
 self.content = +''
 when '<%%'
 content << '<%'
 else
 content << stag
 end
 end

def compile_etag(etag, out, scanner)
 case etag
 when '%>'
 compile_content(scanner.stag, out)
 scanner.stag = nil
 self.content = +''
 when '%%>'
 content << '%>'
 else
 content << etag
 end
 end

def compile_content(stag, out)
 case stag
 when '<%'
 if content[-1] == ?\n
 content.chop!
 out.push(content)
 out.cr
 else
 out.push(content)
 end
 when '<%='
 add_insert_cmd(out, content)
 when '<%#'
 # commented out
 end
 end

def prepare_trim_mode(mode) # :nodoc:
 case mode
 when 1
 return [false, '>']
 when 2
 return [false, '<>']
 when 0
 return [false, nil]
 when String
 perc = mode.include?('%')
 if mode.include?('-')
 return [perc, '-']
 elsif mode.include?('<>')
 return [perc, '<>']
 elsif mode.include?('>')
 return [perc, '>']
 else
 [perc, nil]
 end
 else
 return [false, nil]
 end
 end

def make_scanner(src) # :nodoc:
      Scanner.make_scanner(src, @trim_mode, @percent)
    end

# Construct a new compiler using the trim_mode. See ERB::new for available
    # trim modes.
    def initialize(trim_mode)
      @percent, @trim_mode = prepare_trim_mode(trim_mode)
      @put_cmd = 'print'
      @insert_cmd = @put_cmd
      @pre_cmd = []
      @post_cmd = []
    end
    attr_reader :percent, :trim_mode

# The command to handle text that ends with a newline
    attr_accessor :put_cmd

# The command to handle text that is inserted prior to a newline
    attr_accessor :insert_cmd

# An array of commands prepended to compiled code
    attr_accessor :pre_cmd

# An array of commands appended to compiled code
    attr_accessor :post_cmd

private

# A buffered text in #compile
    attr_accessor :content

def detect_magic_comment(s, enc = nil)
 re = @percent ? /\G(?:<%#(.*)%>|%#(.*)\n)/ : /\G<%#(.*)%>/
 frozen = nil
 s.scan(re) do
 comment = $+
 comment = $1 if comment[/-\*-\s*(.*?)\s*-*-$/]
 case comment
 when %r"coding\s*[=:]\s*([[:alnum:]\-_]+)"
 enc = Encoding.find($1.sub(/-(?:mac|dos|unix)/i, ''))
 when %r"frozen[-_]string[-_]literal\s*:\s*([[:alnum:]]+)"
 frozen = $1
 end
 end
 return enc, frozen
 end
 end
end

#--
# ERB
class ERB
 #
 # Constructs a new ERB object with the template specified in _str_.
 #
 # An ERB object works by building a chunk of Ruby code that will output
 # the completed template when run. If _safe_level_ is set to a non-nil value,
 # ERB code will be run in a separate thread with $SAFE set to the
 # provided level.
 #
 # If _trim_mode_ is passed a String containing one or more of the following
 # modifiers, ERB will adjust its code generation as listed:
 #
 # % enables Ruby code processing for lines beginning with %
 # <> omit newline for lines starting with <% and ending in %>
 # > omit newline for lines ending in %>
 # - omit blank lines ending in -%>
 #
 # _eoutvar_ can be used to set the name of the variable ERB will build up
 # its output in. This is useful when you need to run multiple ERB
 # templates through the same binding and/or when you want to control where
 # output ends up. Pass the name of the variable to be used inside a String.
 #
 # === Example
 #
 # require "erb"
 #
 # # build data class
 # class Listings
 # PRODUCT = { :name => "Chicken Fried Steak",
 # :desc => "A well messages pattie, breaded and fried.",
 # :cost => 9.95 }
 #
 # attr_reader :product, :price
 #
 # def initialize( product = "", price = "" )
 # @product = product
 # @price = price
 # end
 #
 # def build
 # b = binding
 # # create and run templates, filling member data variables
 # ERB.new(<<-'END_PRODUCT'.gsub(/^\s+/, ""), 0, "", "@product").result b
 # <%= PRODUCT[:name] %>
 # <%= PRODUCT[:desc] %>
 # END_PRODUCT
 # ERB.new(<<-'END_PRICE'.gsub(/^\s+/, ""), 0, "", "@price").result b
 # <%= PRODUCT[:name] %> -- <%= PRODUCT[:cost] %>
 # <%= PRODUCT[:desc] %>
 # END_PRICE
 # end
 # end
 #
 # # setup template data
 # listings = Listings.new
 # listings.build
 #
 # puts listings.product + "\n" + listings.price
 #
 # _Generates_
 #
 # Chicken Fried Steak
 # A well messages pattie, breaded and fried.
 #
 # Chicken Fried Steak -- 9.95
 # A well messages pattie, breaded and fried.
 #
 def initialize(str, safe_level=nil, trim_mode=nil, eoutvar='_erbout')
 @safe_level = safe_level
 compiler = make_compiler(trim_mode)
 set_eoutvar(compiler, eoutvar)
 @src, @encoding, @frozen_string = *compiler.compile(str)
 @filename = nil
 @lineno = 0
 end

##
  # Creates a new compiler for ERB.  See ERB::Compiler.new for details

def make_compiler(trim_mode)
    ERB::Compiler.new(trim_mode)
  end

# The Ruby code generated by ERB
  attr_reader :src

# The encoding to eval
  attr_reader :encoding

# The optional _filename_ argument passed to Kernel#eval when the ERB code
  # is run
  attr_accessor :filename

# The optional _lineno_ argument passed to Kernel#eval when the ERB code
  # is run
  attr_accessor :lineno

def location=((filename, lineno))
    @filename = filename
    @lineno = lineno if lineno
  end

#
 # Can be used to set _eoutvar_ as described in ERB::new. It's probably
 # easier to just use the constructor though, since calling this method
 # requires the setup of an ERB _compiler_ object.
 #
 def set_eoutvar(compiler, eoutvar = '_erbout')
 compiler.put_cmd = "#{eoutvar}.<<"
 compiler.insert_cmd = "#{eoutvar}.<<"
 compiler.pre_cmd = ["#{eoutvar} = +''"]
 compiler.post_cmd = [eoutvar]
 end

# Generate results and print them. (see ERB#result)
  def run(b=new_toplevel)
    print self.result(b)
  end

#
  # Executes the generated ERB code to produce a completed template, returning
  # the results of that code.  (See ERB::new for details on how this process
  # can be affected by _safe_level_.)
  #
  # _b_ accepts a Binding object which is used to set the context of
  # code evaluation.
  #
  def result(b=new_toplevel)
    if @safe_level
      proc {
        $SAFE = @safe_level
        eval(@src, b, (@filename || '(erb)'), @lineno)
      }.call
    else
      eval(@src, b, (@filename || '(erb)'), @lineno)
    end
  end

# Render a template on a new toplevel binding with local variables specified
  # by a Hash object.
  def result_with_hash(hash)
    b = new_toplevel(hash.keys)
    hash.each_pair do |key, value|
      b.local_variable_set(key, value)
    end
    result(b)
  end

##
  # Returns a new binding each time *near* TOPLEVEL_BINDING for runs that do
  # not specify a binding.

def new_toplevel(vars = nil)
    b = TOPLEVEL_BINDING
    if vars
      vars = vars.select {|v| b.local_variable_defined?(v)}
      unless vars.empty?
        return b.eval("tap {|;#{vars.join(',')}| break binding}")
      end
    end
    b.dup
  end
  private :new_toplevel

# Define _methodname_ as instance method of _mod_ from compiled Ruby source.
 #
 # example:
 # filename = 'example.rhtml' # 'arg1' and 'arg2' are used in example.rhtml
 # erb = ERB.new(File.read(filename))
 # erb.def_method(MyClass, 'render(arg1, arg2)', filename)
 # print MyClass.new.render('foo', 123)
 def def_method(mod, methodname, fname='(ERB)')
 src = self.src.sub(/^(?!#|$)/) {"def #{methodname}\n"} << "\nend\n"
 mod.module_eval do
 eval(src, binding, fname, -1)
 end
 end

# Create unnamed module, define _methodname_ as instance method of it, and return it.
  #
  # example:
  #   filename = 'example.rhtml'   # 'arg1' and 'arg2' are used in example.rhtml
  #   erb = ERB.new(File.read(filename))
  #   erb.filename = filename
  #   MyModule = erb.def_module('render(arg1, arg2)')
  #   class MyClass
  #     include MyModule
  #   end
  def def_module(methodname='erb')
    mod = Module.new
    def_method(mod, methodname, @filename || '(ERB)')
    mod
  end

# Define unnamed class which has _methodname_ as instance method, and return it.
  #
  # example:
  #   class MyClass_
  #     def initialize(arg1, arg2)
  #       @arg1 = arg1;  @arg2 = arg2
  #     end
  #   end
  #   filename = 'example.rhtml'  # @arg1 and @arg2 are used in example.rhtml
  #   erb = ERB.new(File.read(filename))
  #   erb.filename = filename
  #   MyClass = erb.def_class(MyClass_, 'render()')
  #   print MyClass.new('foo', 123).render()
  def def_class(superklass=Object, methodname='result')
    cls = Class.new(superklass)
    def_method(cls, methodname, @filename || '(ERB)')
    cls
  end
end

#--
# ERB::Util
class ERB
 # A utility module for conversion routines, often handy in HTML generation.
 module Util
 public
 #
 # A utility method for escaping HTML tag characters in _s_.
 #
 # require "erb"
 # include ERB::Util
 #
 # puts html_escape("is a > 0 & a < 10?")
 #
 # _Generates_
 #
 # is a &gt; 0 &amp; a &lt; 10?
 #
 def html_escape(s)
 CGI.escapeHTML(s.to_s)
 end
 alias h html_escape
 module_function :h
 module_function :html_escape

#
    # A utility method for encoding the String _s_ as a URL.
    #
    #   require "erb"
    #   include ERB::Util
    #
    #   puts url_encode("Programming Ruby:  The Pragmatic Programmer's Guide")
    #
    # _Generates_
    #
    #   Programming%20Ruby%3A%20%20The%20Pragmatic%20Programmer%27s%20Guide
    #
    def url_encode(s)
      s.to_s.b.gsub(/[^a-zA-Z0-9_\-.~]/n) { |m|
        sprintf("%%%02X", m.unpack1("C"))
      }
    end
    alias u url_encode
    module_function :u
    module_function :url_encode
  end
end

#--
# ERB::DefMethod
class ERB
 # Utility module to define eRuby script as instance method.
 #
 # === Example
 #
 # example.rhtml:
 # <% for item in @items %>
 # <%= item %>
 # <% end %>
 #
 # example.rb:
 # require 'erb'
 # class MyClass
 # extend ERB::DefMethod
 # def_erb_method('render()', 'example.rhtml')
 # def initialize(items)
 # @items = items
 # end
 # end
 # print MyClass.new([10,20,30]).render()
 #
 # result:
 #
 # 10
 #
 # 20
 #
 # 30
 #
 module DefMethod
 public
 # define _methodname_ as instance method of current module, using ERB
 # object or eRuby file
 def def_erb_method(methodname, erb_or_fname)
 if erb_or_fname.kind_of? String
 fname = erb_or_fname
 erb = ERB.new(File.read(fname))
 erb.def_method(self, methodname, fname)
 else
 erb = erb_or_fname
 erb.def_method(self, methodname, erb.filename || '(ERB)')
 end
 end
 module_function :def_erb_method
 end
end

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