From: Martin DeMello <martindemello@...>
Date: 2003-02-13T21:48:40+09:00
Subject: Re: Should substrings be modifiable in-place??

Chris Pine <nemo@hellotree.com> wrote:
 
> Why not just str.reverse!(x,y) or str.reverse!(x..y) or something?  We could
> do this for reverse (no `!'), too, and probably lots of other String
> methods, to suggest 'only operate on substring'.

class String
  instance_methods.select {|i| i =~ /!$/}.each {|m|
    module_eval <<-here
    def s#{m}(*args)
      a = args.shift
      if (Range === a)
        a, b = a.first, a.last
      else
        b = args.shift
      end
      c = self[a,b]
      self[a,b] = c.send(:#{m},*args)
    end
    here
  }
end

a = "hello world"
a.sreverse!(3,7)
p a #==> "hellrow old"
a.sgsub!(0,5,/l/,'p')
p a #==> "hepprow old"