Hacky completion class in Ruby. Useful for automatically abbreviating commands etc.

completion.rb

require 'fuzzy_match'
require 'amatch'
require 'text'

class Completion
  attr_accessor :keywords

  def initialize( keywords=[] )
    self.keywords = keywords.map(&:downcase)
    ambiguous = true
  end

  def find( s )
    s = s.downcase
    find_partial(s).first     ||
    find_fuzzy(s).first       ||
    find_levenshtein(s).first
  end

  # find by partial matching, taken from goruby
  def find_partial( s )
    regexp = Regexp.new "^#{ s.gsub(/./){ '(.*?)' + Regexp.escape($&) } }"
    keywords.grep(regexp).sort_by do |x|
      x.match(regexp).captures.map(&:size) << x
    end
  end

  # find string with FuzzyMatch
  def find_fuzzy( s )
    FuzzyMatch.new(keywords).find_all(s)
  end

  # find by levenshtein distance
  def find_levenshtein( s )
    keywords.sort_by do |x|
      Text::Levenshtein::distance(s, x)
    end
  end
end