indent_and_wrap.rb

# [See the specs at the bottom for a more verbose description of these requirements]
# A) Indent every line except the first (assume something as wide as INDENT
#     has already been printed) to INDENT spaces in.
# B) Visible characters (non-whitespace) must never exceed WIDTH
#   1) Wrap automatically at word boundary, if there is a boundary within
#       MIN_WIDTH
#   2) Wrap automatically at WIDTH, if there is no boundary within MIN_WIDTH
# C) Preserve existing whitespace (but do not include whitespace at EOL for B)

require 'rubygems'
require 'spec'

class String
  def indent spaces
    if spaces.respond_to? :to_s # duck,
      self.split("\n").map {|s| [spaces, s].join }.join("\n")
    elsif spaces.respond_to? :to_i # duck,
      self.split("\n").map {|s| [(' ' * spaces), s].join }.join("\n")
    else # goose!
      raise ArgumentError, "#{spaces} is neither string-ish nor numeric-ish"
    end
  end
  
  def wrap width
    raise ArgumentError, "#{width} is not numeric-ish" unless width.respond_to? :to_i
    # .{1,#{width}} # Any ammount of anything less than +width+ characters...
    # \b            # ... that ends at a word boundary,
    # [^\w]?        # ... including any punctuation, even over +width+ chars,
    # \s*           # ... don't worry about whitespace after +width+
    self.scan(/.{1,#{width}}(\b[^\w]?)\s*/).join("\n")
  end
end

describe String do
  describe '#indent' do
    it "should indent a single-line string" do
      string = 'abcdef'
      indented = string.indent('  ')
      indented.should == '  abcdef'
    end
    
    it "should indent a multi-line string" do
      string = "abcdef\nghijkl"
      indented = string.indent('  ')
      indented.should == "  abcdef\n  ghijkl"
    end
    
    it "should preserve whitespace" do
      string = "begin\n  puts 'whee!'\nend"
      indented = string.indent('  ')
      indented.should == "  begin\n    puts 'whee!'\n  end"
    end
  end
  
  describe '#wrap' do
    it "should wrap a long, continuous string at `width`" do
      string = '0123456789' * 3
      wrapped = string.wrap(10)
      wrapped.should == "0123456789\n0123456789\n0123456789"
    end
    
    it "should wrap a sentence at the last word boundary before `width`" do
      string = 'The quick blue merle Tucker jumped over the mean black and white Jazz.'
      wrapped = string.wrap(30)
      wrapped.should == "The quick blue merle Tucker \njumped over the mean black and \nwhite Jazz."
    end
  end
end

text-format.rb

# Text::Format doesn't work, see EOF.

require 'rubygems'
require 'text/format'

Formatter = Text::Format.new

Test = "\
0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF
abcdefghi
jklmno
 pqr
stuv
wx
yz!
END OF LINE LAWL"

p Formatter.format(Test) #=> "\
#     0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF 0123456789ABCDEF
# 0123456789ABCDEF 0123456789ABCDEF abcdefghi jklmno pqr stuv wx yz! END
# OF LINE LAWL
# "