From: Gavin Sinclair <gsinclair@...>
Date: 2002-08-04T22:31:02+09:00
Subject: Re: Should this work?


----- Original Message -----
From: "Hal E. Fulton" <hal9000@hypermetrics.com>

[Discussion about += etc. snipped as it's deallt with by other posts.]

> >
> > x, y, z = [], [], []
> > x, y, z << nil        # [nil], [nil], [nil]
> >
> > x, y, z == [nil]      # [true, true, true]
> >
> > (x, y, z).method(arg) # hmm...
>
> Well, = and += are both considered
> assignment operations. That's enough
> rationale (for me) to draw the line
> with +=, -=, and the others.
>
> Truthfully, though, some of your constructs
> above look almost tempting.
>
> I would *not* go for ==, but for << and
> .method  I *might* be persuaded.
>
>
> Hal


The "almost tempting" options are only a "map" away (I prefer :map over
:collect, but don't see much code using it...).

# Sugar:
# x, y, z = [], [], []
# x, y, z << nil            # [nil, nil, nil]

[x, y, z].map { |arr| arr << nil }   # Can also use :each

# Sugar:
# x, y, z == nil            # [true, true, true]

[x, y, z].map { |arr| arr == [nil] }

# Sugar:
# (x, y, z).method(arg)     # hmm...

[x, y, z].map { |obj| obj.method(arg) }

# EOF


Now, I love the "map" method, but sometimes its use is more verbose than it
could be.  It "would be nice" if one could do the following things:

names = %w(john mary adam jacky)
names.map { capitalize }          # -> ["John", "Mary", "Adam", "Jacky"]

x, y, z = [], [], []
[x, y, z].map { $_ << [nil] }     # -> [nil, nil, nil]
[x, y, z].map { $_ == [nil] }     # -> [true, true, true]

Obviously there are limits, but I think that there could be a way to do this
without exposing the language to ambiguity, contradiction, slothfulness or
confused identity (!)  The "capitalize" example may be stretching it a bit
far, but surely the other two examples are good?

What do people think?

--Gavin