Smullyan's birds in Ruby
Ruby
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Failed to load latest commit information.
README.md
chap9.rb

README.md

"To Mock A Mockingbird" combinators in Ruby

To Mock a Mockingbird is a puzzle book by Raymond Smullyan which explains combinatory logic using a metphor of birds in a forest. The birds, which respond when called out to, are used as analogues to combinators.

The code in this repository is an attempt to implement the definitions of combinator birds in Ruby, as an educational excercise.

The book, after defining certain specific birds, provides puzzles to prove various theorems of combinatory logic, culminating in the proof of Godel's incompleteness theorem. It should be obvious that this code makes no attempt to prove any such theorems. It merely implements the combinators, providing opportunities for learning and fun when combining them (pun intended).

The code is structured according to the book, the idea being to follow alongside the chapters.

References http://en.wikipedia.org/wiki/Special:BookSources/0192801422 : The book http://dkeenan.com/Lambda/index.htm : A graphical notation for the birds http://www.cs.virginia.edu/~gms2w/theory/Mockingbird.html : Applet demonstrating the birds, implements beta reduction

License

Copyright (c) 2012 Avik Sengupta All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.