From: stesch@... (Stefan Scholl)
Date: 2001-08-04T20:51:20+09:00
Subject: [ruby-talk:19125] My 1st look @ ruby: No prototypes and problem with String#gsub

My first ruby program:

ruby 1.6.4 (2001-06-04) [i586-linux]
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#! /usr/bin/env ruby

class Shuffle
	def initialize(data)
		raise(TypeError, "not an array") if data.type != Array
		@store = data
		@mark = Array.new
		@marked = 0
	end

	def each
		while @marked < @store.length
			while @mark[i = rand(@store.length)]
			end
			@mark[i] = true
			@marked += 1
			yield @store[i].gsub(/ /, '\\ ')
		end
	end
end

Shuffle.new(ARGV).each {|s| print "#{s} " }
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Is there no way to prototype Shuffle.new()? I've to handle the
wrong type on my own.


And String#gsub seems to have a strange sense of humor regarding
the priorities in the replacement string.
I'd like to use something like

        astr.gsub(/\s/, '\\\&')

irb(main):001:0> astr='abc xzy'
"abc xzy"
irb(main):002:0> astr.gsub(/\s/, '\\\&')
"abc\\&xzy"
irb(main):003:0> astr.gsub(/(\s)/, '\\\1')
"abc\\1xzy"
irb(main):004:0> astr.gsub(/(\s)/, '\\1')
"abc xzy"


In Perl you can write
        $a =~ s/(\s)/\\$1/g;