Re: RFC 237 (v1) hashes should interpolate in double-quoted strings
On Sun, 17 Sep 2000 21:59:47 -0700, Nathan Wiger wrote:
Yeah, I for one think %hashes should be interpolated exactly like
@arrays. It's simple and consistent.
Simple and consistent would be behaviour like
"@{[%hash]}"
However, convenient it is not, getting all key/value pairs in one row.
It's not what was proposed, anyway.
--
Bart.
Re: RFC 237 (v1) hashes should interpolate in double-quoted strings
Chaim Frenkel writes:
What about formating the output as a value that can be used by eval?
%hash = (a = 1, b = 'the world');
print "%{hash}\n";
('a' = 1, 'b'= 'the world')
Interesting.
And as for having to escape % in printf strings. Why not enable the
interpolation if the %{ is seen?
Too inconsistent. People often write dollar amounts, but we don't
only enable scalar interpolation for ${varname}.
Nat
Re: RFC 237 (v1) hashes should interpolate in double-quoted strings
On 17 Sep 2000 23:54:05 -0400, Chaim Frenkel wrote:
What about formating the output as a value that can be used by eval?
%hash = (a = 1, b = 'the world');
print "%{hash}\n";
('a' = 1, 'b'= 'the world')
So, what about arrays? Or scalars?
We have Data::Dumper for that.
--
Bart.
Re: RFC 237 (v1) hashes should interpolate in double-quoted strings
The idea of interpolating a hash is cool... but is seperating each pair by $/ really useful? A comma or $" sees to make more sense. Yeah, I for one think %hashes should be interpolated exactly like @arrays. It's simple and consistent. -Nate
Re: RFC 237 (v1) hashes should interpolate in double-quoted strings
On Sat, Sep 16, 2000 at 03:37:33AM -, Perl6 RFC Librarian wrote:
"%hash" should expand to:
join( $/, map { qq($_$"$hash{$_}) } keys %hash )
So let me get this straight...
%hash = (foo = 42, bar = 13);
print "%hash";
should come out to:
foo 42
bar 13
The idea of interpolating a hash is cool... but is seperating each
pair by $/ really useful? A comma or $" sees to make more sense.
Could you show some examples of practical usage?
--
Michael G Schwern http://www.pobox.com/~schwern/ [EMAIL PROTECTED]
Just Another Stupid Consultant Perl6 Kwalitee Ashuranse
Plus I remember being impressed with Ada because you could write an
infinite loop without a faked up condition. The idea being that in Ada
the typical infinite loop would be normally be terminated by detonation.
-- Larry Wall in [EMAIL PROTECTED]
RFC 237 (v1) hashes should interpolate in double-quoted strings
This and other RFCs are available on the web at
http://dev.perl.org/rfc/
=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 Binput 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 Bthe 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.
