From: Eero Saynatkari <ruby-ml@...>
Date: 2006-02-07T11:09:20+09:00
Subject: Re: ANDCALL / iff? / &? (was Re: ruby-dev summary 28206-28273)

On 2006.02.07 10:03, Evan Webb wrote:
> I'm not sure we even need the 'with' syntax. Even if we do, it breaks
> the programmers context in a way that we might not want to have to
> explain constantly. I can just hear the questions now...
> 
> "Why are my method calls inside a with being executed on the wrong object?"
> 
> "Well, thats because with changes self for it's body, and so you have
> to be careful what you call in there."
> 
> repeat..
> 
> While the more hardcore of us are use to using blocks to enter into
> new and strange contexts (module_eval/class_eval/instance_eval oh
> my!), pushing this to the normal user is not a decision that should be
> made lightly.
> 
> As for the original syntax "&?" I'm against it. It adds a significant
> new level of unreadability. At this stage of the game, any syntax
> changes need to really thought out. We've already got a great,
> expressive syntax. If you want to do away with the duplication of
> effort, use a local variable, thats what there there for:
> 
> if t = a[0] and t.strip.empty?
>    # jump off a bridge
> end
> 
> On a regular basis I write:
> 
> if a = something_long
>    a.another_operation
> end
> 
> The local variable a gets the value "cached" and then we get to do a
> conditional on it's value right away. We've got a language where
> everything is an expression, lets use it!

A minor nitpick, you need

  if (t = something.first) and t.strip.empty?
    # ...
  end

Otherwise a warning will be emitted (sensible behaviour).

>  - Evan
> 
> On 2/3/06, James Britt <ruby@jamesbritt.com> wrote:
> > mathew wrote:
> > >...
> >
> >
> > > with a[1]
> > >  strip!
> > >  empty?
> > > end
> > >
> > > or similar. Hopefully you get the basic idea anyway, and someone can
> > > refine the semantics if they like it...
> >
> >
> > I'm not too keen on terse syntax; clarity for the read takes precedence
> > over ease for the writer.  The 'with' syntax is more expressive.
> >
> >
> > James
> >
> >
> >
> 
> 
> --
> When I do good, I feel good;  when I do bad, I feel bad,
> and that is my religion.
>     -- Abraham Lincoln (1809 - 1865)


E