module Gem::Text

A collection of text-wrangling methods

Public Instance Methods

format_text(text, wrap, indent=0) click to toggle source

Wraps text to wrap characters and optionally indents by indent characters

# File lib/rubygems/text.rb, line 12
def format_text(text, wrap, indent=0)
  result = []
  work = text.dup

  while work.length > wrap do
    if work =~ /^(.{0,#{wrap}})[ \n]/ then
      result << $1.rstrip
      work.slice!(0, $&.length)
    else
      result << work.slice!(0, wrap)
    end
  end

  result << work if work.length.nonzero?
  result.join("\n").gsub(/^/, " " * indent)
end
levenshtein_distance(str1, str2) click to toggle source

This code is based directly on the Text gem implementation Returns a value representing the “cost” of transforming str1 into str2

# File lib/rubygems/text.rb, line 41
def levenshtein_distance str1, str2
  s = str1
  t = str2
  n = s.length
  m = t.length
  max = n/2

  return m if (0 == n)
  return n if (0 == m)
  return n if (n - m).abs > max

  d = (0..m).to_a
  x = nil

  str1.each_char.each_with_index do |char1,i|
    e = i+1

    str2.each_char.each_with_index do |char2,j|
      cost = (char1 == char2) ? 0 : 1
      x = min3(
           d[j+1] + 1, # insertion
           e + 1,      # deletion
           d[j] + cost # substitution
          )
      d[j] = e
      e = x
    end

    d[m] = x
  end

  return x
end