Simple implentation for embedding mustache template in a script

own-mustache.rb

#!/usr/bin/ruby
# Copyright (c) 2010 Jonathan Stott, unless otherwise noted
#
# Permission  is  hereby granted, free of charge, to any person ob-
# taining a copy of  this  software  and  associated  documentation
# files  (the "Software"), to deal in the Software without restric-
# tion, including without limitation the rights to use, copy, modi-
# fy, merge, publish, distribute, sublicense, and/or sell copies of
# the Software, and to permit persons to whom the Software is  fur-
# nished to do so, subject to the following conditions:
#
# The  above  copyright  notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF  ANY  KIND,
# EXPRESS  OR  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE  AND  NONIN-
# FRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER  IN  AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN  THE
# SOFTWARE.
require 'mustache'

class Mustache

  class OwnMustacheNotFound < StandardError
    def initialize(message="Have you shaved today?")
      super(message)
    end
  end

  def self.own(context={})
    own_template = find_own_template
    raise OwnMustacheNotFound if own_template.nil?
    own_template.strip! # oh my!
    render(own_template, context)
  end

#  The following methods are flat out lifted, or heavily based on methods
#  taken from sinatra/base.rb
#
#  Copyright (c) 2007, 2008, 2009 Blake Mizerany
#
#  Permission is hereby granted, free of charge, to any person
#  obtaining a copy of this software and associated documentation
#  files (the "Software"), to deal in the Software without
#  restriction, including without limitation the rights to use,
#  copy, modify, merge, publish, distribute, sublicense, and/or sell
#  copies of the Software, and to permit persons to whom the
#  Software is furnished to do so, subject to the following
#  conditions:
#
#  The above copyright notice and this permission notice shall be
#  included in all copies or substantial portions of the Software.
#
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
#  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
#  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
#  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
#  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
#  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
#  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
#  OTHER DEALINGS IN THE SOFTWARE.
  def self.find_own_template
    file = caller_files.first

    begin
      app, data =
        ::IO.read(file).gsub("\r\n", "\n").split(/^__END__$/, 2)
    rescue Errno::ENOENT
      app, data = nil
    end
    data
  end

  CALLERS_TO_IGNORE = [
    /own-mustache\.rb$/,   # ourself.
    /\(.*\)/,              # generated code
    /custom_require\.rb$/, # rubygems require hacks
    /active_support/,      # active_support require hacks
  ]

  # add rubinius (and hopefully other VM impls) ignore patterns ...
  CALLERS_TO_IGNORE.concat(RUBY_IGNORE_CALLERS) if defined?(RUBY_IGNORE_CALLERS)

  # Like Kernel#caller but excluding certain magic entries and without
  # line / method information; the resulting array contains filenames only.
  def self.caller_files
    caller_locations.
      map { |file,line| file }
  end

  def self.caller_locations
    caller(1).
      map    { |line| line.split(/:(?=\d|in )/)[0,2] }.
      reject { |file,line| CALLERS_TO_IGNORE.any? { |pattern| file =~ pattern } }
  end
end