= irb_callbacks

* http://rubysideshow.rubyforge.org/irb_callbacks

== DESCRIPTION:

This gem adds callbacks to irb, intended for you to
override at your discretion.

== FEATURES:

irb's control flow looks like this:

loop:
* prompt
* eval
* output

This gem adds three callbacks to each phase.

module IRB:

* self.before_prompt
* self.around_prompt (call yield)
* self.after_prompt

* self.before_eval
* self.around_eval (call yield)
* self.after_eval

* self.before_output
* self.around_output (call yield)
* self.after_output

== SYNOPSIS:

# Here's my ~/.irbrc file (which is run at irb startup)

require 'rubygems'
require 'irb_callbacks'
require 'benchmark'

# This little snippet will time each command run via the console.

module IRB
def self.around_eval(&block)
@timing = Benchmark.realtime do
block.call
end
end

def self.after_output
puts "=> #% @timing seconds"
end
end

# And a sample irb session:

$ irb
irb(main):001:0> 1_000_000.times { |x| x + 1 }
=> 1000000
=> 0.330 seconds

== CAVEATS:

The three around_* callbacks all require you to call the
block that's passed in. If you don't do it, undefined
behavior may occur.

== INSTALL:

* sudo gem install irb_callbacks

== LICENSE:

(The MIT License)

Copyright (c) 2008 Mike Judge

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.