From: Robert Dober <robert.dober@...>
Date: 2007-05-31T18:51:53+09:00
Subject: Re: Underscore

On 5/31/07, Robert Klemme <shortcutter@googlemail.com> wrote:
> On 30.05.2007 22:36, Robert Dober wrote:
> > On 5/30/07, Logan Capaldo <logancapaldo@gmail.com> wrote:
> >> On 5/30/07, Robert Dober <robert.dober@gmail.com> wrote:
> >> >
> >> > On 5/30/07, Brian Candler <B.Candler@pobox.com> wrote:
> >> > > On Wed, May 30, 2007 at 07:50:05AM +0900, Logan Capaldo wrote:
> >> > > > On 5/29/07, Robert Klemme <shortcutter@googlemail.com> wrote:
> >> > > > >
> >> > > > >
> >> > > > >I was too fast (again).  Even though the return value is used, I'd
> >> > rather
> >> > > > >do
> >> > > > >
> >> > > > >n.times { x = yield x }
> >> > > > >
> >> > > > >than using #inject which does more than needed in this case.  :-)
> >> > > > >
> >> > > > >Now, did I look at all aspects...?
> >> > > >
> >> > > >
> >> > > > Almost.
> >> > > > you'd actually need
> >> > > > n.times { x = yield x }
> >> > > > x
> >> > >
> >> > > Almost almost :-)
> >> > >
> >> > > x = nil
> >> > > n.times { x = yield x }
> >> > > x
> >> > >
> >> > >
> >> > Robert was very quick indeed, he did not repeat the context of the
> >> > expression which was
> >> >
> >> > def forgot_the_name(x,...)
> >> >     n.times{ x = yield x }
> >>
> >>
> >>       Still need x here
> >>
> >> end
> >> >
> >> > Now it works ;)
> >>
> >>
> >> No it doesn't ;)  n.times {  ... } returns n.
> > Obviously I am too stupid to test, sorry, I did test it, who knows how ;)
> > Seriously I do know now, n just was the expected result of the block :(
> >
> > def anyhow(count, x)
> >  count.times{x=yield x}
> >  x
> > end
> >
> > Maybe we can still agree that this is better than inspect ;)
> > And yes thanks for the Ruby classes I got.
>
> Hm...  Thinking a bit more about this I am not sure I'd stick with my
> proposal.  I think I'd probably do
>
> irb(main):001:0> require 'enumerator'
> => true
> irb(main):002:0> def rep(n,init=nil) n.to_enum(:times).inject(init)
> {|x,| yield x} end
> => nil
> irb(main):003:0> rep(5,"x") {|s| puts s; s<<"."}
> x
> x.
> x..
> x...
> x....
> => "x....."
>
> Hmm...
As we are fooling around ;)

class Integer
  alias_method :good_old_times, :times
  def times
    r = nil
    good_old_times do
      |n|
      r = Proc.new.call n
    end
    r
  end

  def rep init = nil
    times do
       init = Proc.new.call init
    end
  end
end


puts 5.times{ |x| 2*x }
puts 5.rep(12){ |x| x+1 }
BTW what is this good for anyway ;) for loops???

Cheers
Robert


-- 
You see things; and you say Why?
But I dream things that never were; and I say Why not?
-- George Bernard Shaw