From: "Brian Schröder" <ruby.brian@...>
Date: 2005-10-20T22:55:56+09:00
Subject: Re: Unit testing an each function

On 20/10/05, Kevin Ballard <kballard@gmail.com> wrote:
> Brian Schr�der wrote:
> > > [snip]
> > >
> > >   (1..100).reject.even?
> > >
> > > [snip]
> >
> > Just wanted to state that on second reading of this thread it again
> > did hurt in my eyes. If I read (1.100).reject I expect a resulting
> > array. And when I read the above I wondered shortly if even? works on
> > arrays maybe returning true if the array has an even number of
> > entries. Then I remembered the thread topic and started this text. So
> > a
> >   -1
> > from me for proposing this as an addition to the language.
>
> Except that (1..100).reject doesn't return an array at all unless a
> block is supplied - it gives a LocalJumpError. All the enumerating
> methods I've tested except for Enumerable#collect give an error when
> called without a block (#collect without a block is equivalent to
> #to_a). So with this change, the case where no block is supplied
> becomes useful as opposed to useless (and in the #collect case, I can't
> imagine anybody's actually relying on #collect being equivalent to
> #to_a when called without a block, because they should be using #to_a
> directly for that).
>
> In any case, I wasn't proposing this as an addition to the language
> (not that I would mind), I was simply proposing this as something I
> should package up into a gem so people could use it if they wanted.
>

Hello Kevin,

it is clear that reject without a block does not work, it was more a
question of visual parsing. Reject without a block has no meaning,
because we need to tell what to reject. And telling this is done with
a block. Your quite intelligent magic gives IMHO a wrong meaning to
the dot operator. You seem not to call .even? on the result of a
reject.

Well effectively you do, but I read chained methods as doing a chain
of succeding operations on a chain of objects, and that is not what I
read when I read (1..100).reject.even? Therefore I proposed
(1..100).reject :even?, because there it is made clearer that even is
given to reject to do something.

Nonetheless go ahed and package it as a gem. I just wanted to voice
what was disturbing me with this syntax.

Best regards,

Brian

--
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