From: Chris Pine <nemo@...>
Date: 2002-12-30T03:22:31+09:00
Subject: capturing puts in mod_ruby

Hello,

In order to run code samples for the tutorial I am writing, I essentially do
the following:

  strIO = StringIO.new
  if !input.empty?
    input = input.join("\n")+"\n"
    input = StringIO.new (input, "r")
    class << strIO; self; end.class_eval do
      ['gets', 'getc', 'read'].each do |meth|
        define_method(meth) do
          inStr = input.method(meth).call
          puts inStr.chomp  #  Echo input.
          inStr
        end
      end
    end
  end

  strIO.instance_eval code

This works pretty well.  However, what if the code I was trying to run did
something like this?

  class Foo
    def foo
      puts 'Foo#foo was called.'
    end
  end

  Foo.new.foo

This is not doing the StringIO puts, but the Kernel puts instead.
(Actually, it does some sort of special mod_ruby puts which spits the output
straight to the browser, which REALLY screws things up for me.)  Anyone know
how to fix something like this?  Perhaps I can do something like mod_ruby
does (redefining puts), but how is mod_ruby doing it?

Many thanks for any help,

Chris