module Gem::Text - RDoc Documentation

# module Gem::Text

A collection of text-wrangling methods

### Public Instance Methods

clean_text(text) click to toggle source

Remove any non-printable characters and make the text suitable for printing.

    # File lib/rubygems/text.rb, line 11
    def clean_text(text)
      text.gsub(/[\000-\b\v-\f\016-\037\177]/, ".".freeze)
    end

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 25
    def format_text(text, wrap, indent=0)
      result = []
      work = clean_text(text)

      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 54
    def levenshtein_distance str1, str2
      s = str1
      t = str2
      n = s.length
      m = t.length

      return m if (0 == n)
      return n if (0 == m)

      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

truncate_text(text, description, max_length = 100_000) click to toggle source

    # File lib/rubygems/text.rb, line 15
    def truncate_text(text, description, max_length = 100_000)
      raise ArgumentError, "max_length must be positive" unless max_length > 0
      return text if text.size <= max_length
      "Truncating #{description} to #{max_length.to_s.reverse.gsub(/...(?=.)/,'\&,').reverse} characters:\n" + text[0, max_length]
    end