From: Christian Neukirchen <chneukirchen@...>
Date: 2005-09-11T20:38:08+09:00
Subject: Re: r4 - the simplest ruby pre-processor

"Ara.T.Howard" <Ara.T.Howard@noaa.gov> writes:

> all this talk about pre-processors and erb got me thinking : what would it
> take to code up a ruby pre-procssors that could be used for any laguange.  my
> first crack is 38 lines of ruby that pre-process any files on the command line
> (or stdin) using ruby as the macro language and a convenience function 'macro'
> which can be used to define ruby methods which return test that is used as
> output.  functions declared this way need not do any explicit io.

Alternative implementation ("r5"):

    def macro(name, &block)
      Kernel.send(:define_method, name) { |*args|
        puts block.call(args)
      }
    end

    send(($DEBUG ? "puts" : "eval"), ARGF.readlines.map { |line|
      if line[0] == ?|
        line[1..-1]
      else
        "puts #{line.chomp.dump}\n"
      end
    }.join)

Happy hacking,
-- 
Christian Neukirchen  <chneukirchen@gmail.com>  http://chneukirchen.org