From: dblack@...
Date: 2003-05-30T10:41:21+09:00
Subject: Re: Array.extend versus instance.extend

Hi --

On Fri, 30 May 2003, Simon Strandgaard wrote:

> On Fri, 30 May 2003 01:15:32 +0900, Guillaume Marcais wrote:
>
> > module ArrayMisc2
> >   def shift_until(klass)
> >     p = -1
> >     detect { |x| p += 1; klass === x }
> >     slice!(0, p)
> >   end
> >   def pop_until(klass)
> >     p = -1
> >     reverse.detect { |x| p += 1; klass === x }
> >     slice!(-p, p)
> >   end
> > end
>
>
> Sorry your code does not pass all the tests.. it has somekind of
> different behavier. I have never tried using 'Enumable#detect' before
> so I cannot figure out exactly what seems to be the problem.
> Thanks for trying :-)

#detect returns the first element for which the block is true, passing
each element to the block in turn:

  [1,2,3,4].detect {|e| e > 2}    # 3

Here's a modification of Guillaume's code that passes your tests:

  module ArrayMisc2A
    def shift_until(klass)
      p = 0
      detect { |x| p += 1 and klass === x }
      slice!(0, p)
    end

    def pop_until(klass)
      p = 0
      reverse.detect { |x| p += 1 and klass === x }
      slice!(-p, p)
    end
  end


David

-- 
David Alan Black
home: dblack@superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav