Class RegexList
In: lib/regex_list.rb
Parent: Object
Copyright:Copyright (c) 2005 Nicolas Pouillard. All rights reserved.
Author:Nicolas Pouillard <ertai@lrde.epita.fr>.
License:Gnu General Public License.
Revision:$Id: /w/fey/ruby_ex/trunk/lib/regex_list.rb 21865 2006-02-18T17:13:28.680350Z pouillar $

Methods

[]   new   score   score   score_without_cache  

Classes and Modules

Module RegexList::Assertions
Module RegexList::PathListExtension

Public Class methods

new( *args )

[Source]

# File lib/regex_list.rb, line 8
  def initialize ( *args )
    @regexps = args.flatten
    @regexps.map! { |re| (re.is_a? Regexp)? re : Regexp.new(re) }
    @regexps.reverse!
    @scores = {}
  end

Public Instance methods

[]( score )

[Source]

# File lib/regex_list.rb, line 61
  def [] ( score )
    @regexps[score]
  end
score( aString )

[Source]

# File lib/regex_list.rb, line 19
    def score ( aString )
      if @scores.has_key? aString
        result = @scores[aString]
        action = '<%= color "Hit ", :green %>'
      else
        result = score_without_cache(aString)
        action = '<%= color "Miss", :red %>'
        @scores[aString] = result
      end
      @@h.say "#{action}: #{aString} -> #{result.inspect}"
      result
    end
score( aString )

Perform a cache over score_without_cache

[Source]

# File lib/regex_list.rb, line 35
    def score ( aString )
      return @scores[aString] if @scores.has_key? aString
      return @scores[aString] = score_without_cache(aString)
    end
score_without_cache( aString )

Score represent a weighted sum of the match result with each regexp.

0: Not matched at all 1: Just the last regexp matches (the Nth regexp) 2: Just the (N - 1)th matches 3: The Nth and the (N - 1)th 2^(N - 1): Just the first one matches

Formula: 

  U(i <- 0 .. N - 1) is a vector with 1 when it matches and 0 otherwise
  Score = U(N - 1) * 2^(N - 1) + U(N - 2) * 2^(N - 2) + ... + U(0) * 2^0

[Source]

# File lib/regex_list.rb, line 53
  def score_without_cache ( aString )
    result = 0
    @regexps.each_with_index do |re, i|
      result += 2 ** i if aString =~ re
    end
    return result
  end

[Validate]