From: Charles Oliver Nutter <charles.nutter@...>
Date: 2008-08-01T08:33:15+09:00
Subject: [ruby-core:18036] Re: New array methods cycle, choice, shuffle (plus bug in cycle)

Restarting this thread because I missed it the first time around and 
because I agree it should be "choose" rather than "choice" if it's going 
to be in. Also, it doesn't appear to have been settled the first time.

choice is a noun. choose, map, select, collect, etc are imperative 
verbs. So choose much more consistent with the others. Also, choice 
implies to me that it's already been made...since you can't have a 
choice unless you've already made a "choice". In essence, a "choice" is 
the product of "choosing" something. So ary.choose produces a choice.

- Charlie

David Flanagan wrote:
> Four new methods have been added to Array the Ruby 1.9 trunk.  I've got 
> a couple of questions and comments and one bug report:
> 
> cycle is an iterator that is like calling each on the array within an 
> infinite loop. Matz: have you considered generalizing this to be a 
> method of Enumerable?
> 
> cycle has what I'd consider a bug: call it on an empty array and it will 
> never return and will never invoke the associated block.
> 
>     ruby1.9 -e '[].cycle {}'
> 
> When I do this I can't even ^C to stop ruby. I have to kill -9 the 
> process. I'd suggest that cycle simply return when the array is empty. 
> That is, it cycles until the array becomes empty (which will be forever 
> in most cases).  The patch I propose is at the bottom of this message.
> 
> choice returns a random element from the array.  I don't like the name 
> of this method: neither the word "choice" nor it verb form "choose" 
> imply randomness--instead they suggest the opposite.  I suggest just 
> using the name "rand", "random" or "random_element". Most array methods 
> are verbs, but a noun here would match the existing methods first and 
> last.  Also, may I suggest a random! variant of the method that returns 
> *and removes* a random element from the array?  first and last already 
> have shift and pop to serve this purpose.
> 
> shuffle and shuffle! randomly permute an array and seem worth having.  I 
> think I remember Josh Bloch (author of the Java collections library) 
> writing somewhere that shuffling an array correctly is actually kind of 
> hard to do, so I think it is great to have these methods, even if I 
> can't think of a use case right now :-)
> 
>     David
> 
> --- array.c.orig        2007-09-06 15:00:02.000000000 -0700
> +++ array.c     2007-09-06 15:03:30.000000000 -0700
> @@ -2940,6 +2940,7 @@
> 
>      RETURN_ENUMERATOR(ary, 0, 0);
>      for (;;) {
> +       if (RARRAY_LEN(ary) == 0) return Qnil;
>         for (i=0; i<RARRAY_LEN(ary); i++) {
>             rb_yield(RARRAY_PTR(ary)[i]);
>         }
> 
>