Larry Wall wrote: > On the other hand, -<> makes a pretty pathetic fish operator. So for > the sake of argument, let's keep it =<> for the moment. But ignoring the > tail leads us to the head end of the fish. What do we do about $ARGS? > We could say this: > > =$fh : *$fh :: =<> : *<> > > Now if you analyze *<> as a unary * plus a null list, it's obviously > stupid to be interpolating 0 arguments at this point, so pragmatically > speaking something else is meant by this utterance, and we could make > it mean "read all the lines of $ARGV" easily enough.
On the other hand, maybe * plus a null list, namely *(), has a higher
purpose, where it can mean *$/, which is very very very useful. To wit:
grammar Java;
rule statement {
| <block>
{ Block.new(*()) } # Java::Block.new(block => $<block>)
| if \( $<cond> := <expr> \) <statement>
[ else $<else_statement> := <statement> ]?
{ If.new(*()) }
| for \(
<init> ;
$<cont> := <expr>? ;
$<next> := <expr>
\)
<statement>
{ For.new(*()) }
| ...
}
I think *() above is more visually distinct than *$/.
> (Presumably the @ forms would be for rvalue use only--at least till MJD
> gets ahold of them--but I don't think that's terribly important one way
> or the other in a huffman fight.)
Lvalue @$fh can be fun too indeed, but I guess it depends on how the $fh
is constructed. :-)
> Another option is to just give up on the <> meme. We just invented the
> Whatever token *, so maybe in an iterator context Whatever means $ARGS.
> Then we get =* as reading a line from $ARGS, and @* perhaps as reading
> all the lines, or @(*) if you're worried about the twigilhood of *.
I think I like this alternative best. The <> meme never really felt
comfortable to me, as the empty string-list "magic" may be too much magic.
> If we do say that $fh.as(Array) pulls all the lines from the
> iterator destructively (though lazily), then it logically follows
> that $fh.as(Scalar) pulls one line. Which means instead of
>
> say(=$fh, =$fh, =$fh); # print three lines
>
> you'd just say
>
> say($$fh, $$fh, $$fh); # print three lines
One problem is that while repeated @$fh conceptually returns the same
thing, $$fh here would iterate instead of merely dereference, which
makes it carry its own state. If "=" means something like "each(%kv)"
in Perl 5, and we get [EMAIL PROTECTED] as well for iterating over elements,
then
it makes more sense for that purpose for =$fh as well.
Thanks,
Audrey
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