Simple Implementation of Chinese Whispers. Supports varying iterations and percent change.

chinese-whispers.rb

# Chinese Whispers
#
# author: Calum Gilchrist
#
# Experiment to distort a string based on the number of nodes between the 
# sender and recipient
#

require 'raspell'
require 'optparse'

# Take a string and return a malformed string
#
# Each word in the string has a percentage chance of being replaced with a 
# similar word.
#
# str - Input string
# percent - (float) How often the word is altered
#
# Example:
#       pass_and_receive('There's a sniper over the top of the hill.', 0.05)
#       => 'There a sander over the top's of the hill.'
# Returns a string that might not be quite the same as the original
def pass_and_receive(str, percent)

    speller = Aspell.new("en_GB")
    speller.suggestion_mode = Aspell::NORMAL

    words = str.split

    trans_words = []
    
    rand = Random.new
    words.each do |word|
        if rand.rand > percent
            trans_words.push word 
        else
            # Use a suggested word as a replacement
            suggested = speller.suggest(word)
            trans_words.push suggested.sample
        end
    end

    new_str = trans_words.join ' '
end

options = {}

OptionParser.new do |opts|

    opts.banner = 'Usage: chinese-whsipers.rb string [-p PERCENT]'

    options[:percent] = 0.05
    opts.on('-p', '--percent PERCENT', 'Percent word transformation') do |percent|
        options[:percent] = percent.to_f / 100
    end

    options[:count] = 9
    opts.on('-c', '--count COUNT', 'Number of Iterations') do |count|
        # Subtract 1 for counting from 0
        options[:count] = count.to_i - 1
    end
end.parse!

if ARGV.empty?
    puts "Not enough arguments"
    exit(2)
end

message = ARGV.join ' '

(0..options[:count]).each do |i|
    puts message

    message = pass_and_receive(message, options[:percent])
end