From: Trans <transfire@...>
Date: 2005-08-06T00:51:06+09:00
Subject: Re: new block notation


David A. Black wrote:
> > Nah, just use the _collection_ brackets for both array and hash. The
> > parser can tell them apart:
> >
> >  # array
> >  [ a, b, c ]
> >
> >  # hash
> >  [ a=>x, b=>y, c=>z ]
> >  [ a: x, b: y, c: z ]
>
> I don't like to have to scan visually for a separator in order to know
> what the [ meant.  That seems ad hoc and fragile.
>

David,

Yes, contrary to you other post, there are already "scanning" to be
done. Eg.

  def ameth(n=nil,&b)
    # ...
  end

Is it a hash or a block?

  ameth {[1032,12,34,89].collect{|x|x*7+3}.join('->');7+15**2}

  ameth {[1032,12,34,89].collect{|x|x*7+3}.join('->'),7+15**2}

I'm sure others can provide even better examples. But the point really
is that the "=>" (or ": ") is a equally as important visual cue that
stands out in the scanning, and is usually just a few charactes in.
Personally I have never written a hash without it. Thus using [ ... ]
in place of { ... } would at the least be no more or less difficult.
But would prove better in one respect --that the purely comma hash
noation would no longer be valid and a "=>" or ":" has to always be
used. That's a readability improvement in my mind.

T.

P.S. Might it help clear up ambiguity of '(1,2,3)' which is currently a
syntax error? Why can't that be parsed as an array?