From: blondinet <jblondinet@...>
Date: 2008-01-14T02:24:58+09:00
Subject: Re: Callable class with block

On 13 jan, 10:56, Todd Benson <caduce...@gmail.com> wrote:
> On Jan 12, 2008 11:54 AM, blondinet <jblondi...@yahoo.com> wrote:
>
>
>
> > Hi everyone,
>
> > I would like to know why the following code does not work :
> > -----
> > class A
>
> >   def A.[](*args,&block)
> >     result = self.new( *args )
> >     if block
> >       yield result
> >       result.end
> >     end
> >     return result
> >   end
>
> >   def end()
> >     puts "end"
> >   end
>
> > end
>
> > A[] do |a|
> >   puts "a #{a.inspect}"
> > end
>
> That is interesting.  With 1.8.6, I get results like this...
>
> irb(main):001:0> class C
> irb(main):002:1>   def []
> irb(main):003:2>     yield
> irb(main):004:2>   end
> irb(main):005:1> end
> => nil
> irb(main):006:0 c = C.new
> => #<C:0x2dfac1c>
> irb(main):007:0> c[]
> LocalJumpError: no block given  <<<interesting part
>       from (irb):3:in `[]'
>       from (irb):7
> irb(main):008:0> c[] {}
> SyntaxError: compile error
> (irb):8: syntax error, unexpected '{', expecting $end
> c[] {}
>      ^
>       from(irb):8
> irb(main):009:0> c.[] {}
> => nil
>
> Bug maybe?  I can't think of a reason why the parser would need to
> separate [] from .[]
> Hmm...
>
> Todd

Thanks Todd for your analysis.
Your example is even striking than mine, and I share your opinion on
this strange "feature" : that a block is required and cannot be given
with the same syntax seems to me a bit "ugly".
Any other opinion ? As a beginner on this forum, I do not know yet
what to do with this ...