method

abbrev

v1_8_7_330 - Show latest stable - 0 notes - Class: Abbrev

abbrev(words, pattern = nil) public

Given a set of strings, calculate the set of unambiguous abbreviations for those strings, and return a hash where the keys are all the possible abbreviations and the values are the full strings. Thus, given input of “car” and “cone”, the keys pointing to “car” would be “ca” and “car”, while those pointing to “cone” would be “co”, “con”, and “cone”.

The optional pattern parameter is a pattern or a string. Only those input strings matching the pattern, or begging the string, are considered for inclusion in the output hash

Show source

# File lib/abbrev.rb, line 44
  def abbrev(words, pattern = nil)
    table = {}
    seen = Hash.new(0)

    if pattern.is_a?(String)
      pattern = /^#{Regexp.quote(pattern)}/     # regard as a prefix
    end

    words.each do |word|
      next if (abbrev = word).empty?
      while (len = abbrev.rindex(/[\w\W]\z/)) > 0
        abbrev = word[0,len]

        next if pattern && pattern !~ abbrev

        case seen[abbrev] += 1
        when 1
          table[abbrev] = word
        when 2
          table.delete(abbrev)
        else
          break
        end
      end
    end

    words.each do |word|
      next if pattern && pattern !~ word

      table[word] = word
    end

    table
  end

abbrev

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