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=head1 TITLE
hashes should interpolate in double-quoted strings
=head1 VERSION
Maintainer: Nathan Torkington <[EMAIL PROTECTED]>
Date: 15 Sep 2000
Mailing List: [EMAIL PROTECTED]
Number: 237
Version: 1
Status: Developing
=head1 ABSTRACT
"%hash" should expand to:
join( $/, map { qq($_$"$hash{$_}) } keys %hash )
=head1 DESCRIPTION
Hashes do not interpolate in double-quote context in perl5. They
should, because (a) scalars and arrays do, (b) it is a useful
thing.
The problem has always been: how to separate the keys and values? I
say use $" (the value that gets put between array elements in
double-quote interpolation) between key and value, and $/ between each
hash record.
A thorn is that $/ is the B<input> record separator. It seems wrong
to use it for output. But $\ is not set by default, and it seems
unreasonable to have to set $\ (which affects the end of every print)
just to interpolate hashes. I didn't relish making yet another
special variable just for this, though.
When global variables like $" and $/ go away, I imagine they'll be
replaced with lexically-scoped variations. This will work then, too.
The big problem is that % is heavily used in double-quoted strings
with printf. I don't have a solution to this. In the end, this may
be B<the> definitive reason why hashes do not interpolate. And that's
fine by me.
=head1 IMPLEMENTATION
A simple change to the tokenizer.
The perl526 translator could backslash every % in a double-quoted
string.
=head1 REFERENCES
None.
