This and other RFCs are available on the web at
http://dev.perl.org/rfc/
=head1 TITLE
Add new C<empty> keyword to DWIM for clearing values
=head1 VERSION
Maintainer: Nathan Wiger <[EMAIL PROTECTED]>
Date: 16 Sep 2000
Mailing List: [EMAIL PROTECTED]
Number: 245
Version: 1
Status: Developing
=head1 ABSTRACT
Most beginners and even intermediate users expect this:
my @array = undef;
undef @array;
To initialize an empty array. It doesn't, and shouldn't. This RFC
proposes a new keyword, C<empty>, which does the "right thing", and can
be used as both a noun and verb:
my @array = empty;
empty @array;
The idea is to make this process more intuitive. It also makes a few
things easier.
=head1 DESCRIPTION
Currently, initializing values so that warnings are spewed out or
confusion doesn't arise is not as easy as it could be. These:
my $name = undef;
my($a, $b, $c, $d, $e, $f) = undef;
my(@name, $age, %attrs) = undef;
Don't do what many (most?) people expect them to. Getting the
corresponding effects that most people want can be cumbersome and not
always intuitive:
my $name = '';
my($a, $b, $c, $d, $e, $f) = ( '' x 6 );
my @name = (); my $age = ''; my %attrs = ();
With the new C<empty> keyword, this becomes easier and more readable,
with a nice parallel to C<undef>:
my $name = empty;
my($a, $b, $c, $d, $e, $f) = empty;
my(@name, $age, %attrs) = empty;
Like C<undef>, it also has the benefit of being usable on values
themselves as a verb:
empty @array; # @array = ();
empty %hash; # %hash = ();
empty @array, $name; # @array = (); $name = '';
And its purpose is intuitive: It causes a value to become C<empty>,
without being undefined. Note that it can also shorten code in some
situations.
=head1 NOTES
I'm throwing this out there. It seems to me to make easy things easier,
and seems to potentially make the teaching of undef easier as well,
since the usage of C<undef> and C<empty> are parallel. The point of
debate I'm sure will be whether or not it hides implicit contexts, but
it doesn't seem that it would have to assuming that it was properly
integrated into the undef/context part of a course.
Nonetheless, feel free to point out why this is a bad idea and I'll
gladly retract it.
=head1 IMPLEMENTATION
See here in v2, assuming this doesn't get ripped apart.
=head1 MIGRATION
None. New functionality.
=head1 REFERENCES
http://www.mail-archive.com/perl6-language@perl.org/msg03703.html
And a previous, humorous yet poignant one from Tom C which appears to
have vanished
