It's here, it's groovy, it's the subject of a lightning talk.
http://unixbeard.net/~richardc/lab/Sub-Parameters/Sub-Parameters-0.01.tar.gz
--
Richard Clamp <[EMAIL PROTECTED]>
NAME
Sub::Parameters - enhanced parmeter handling
SYNOPSIS
use Sub::Parameters;
sub foo : WantParam {
my $foo : Parameter;
my $bar : Parameter(rw);
$bar = 'foo';
print "the foo parameter was '$foo'\n";
}
my $foo = 'bar';
print "foo is '$foo'; # prints bar
foo(1, $foo);
print "foo is now '$foo'; # prints foo
DESCRIPTION
Sub::Parameters provides a syntactic sugar for parameter parsing.
It's primary interface is via attributes, you first apply notation to
the subroutine that you wish it to use extended parameter passing, and
of what style with the WantParams attribute. You can then annotate which
lexicals within that subroutine are to be used to receive parameters.
There are currently two styles of argument parsing supported
"positional" and "named".
Positional parameters
With the "positional" scheme parameters are assigned from @_ in the same
order as in the program text, as we see in the following example.
sub example : WantParams(positional) {
my $baz : Parameter;
my $bar : Parameter;
print $bar; # prints 'first value'
print $baz; # prints 'second value'
}
example( 'first value', 'second value' );
Positional is the default scheme.
Named parameters
With the "named" scheme parameters are assigned from @_ as though it was
an arguments hash, with the variable names as keys.
sub demonstration : WantParams(named) {
my $bar : Parameter;
my $baz : Parameter;
print $bar; # prints 'bar value'
print $baz; # prints 'baz value'
}
demonstration( foo => 'foo value',
baz => 'baz value',
bar => 'bar value' );
Readwrite parameters
Both positional and named parameters may be marked as readwrite ("rw" in
the code.) A readwrite parameter is passed by reference so modifying the
value within the subroutine modifies the original.
sub specimen : WantParams {
my $foo : Parameter(rw);
print $foo; # prints 'foo value'
$foo = "new value";
}
my $variable = "foo value";
specimen( $variable );
print $variable; # prints 'new value'
Alternate parameter syntax
For versions of perl older than 5.7.3 or 5.8.0 lexical attributes have
an implementation flaw. In this case there is an alternative syntax for
identifying parameters:
use Sub::Parameters 'Param';
sub illustration: WantParams {
Param( my $foo );
Param( my $bar, 'rw' );
...
}
TODO
Think about positional @foo:Parameter slurp rather than @foo = []
semantics
think about methods
SEE ALSO
"Attribute::Handlers", "PadWalker", "Hook::LexWrap", "Devel::LexAlias"
AUTHOR
Richard Clamp <[EMAIL PROTECTED]>
COPYRIGHT
Copyright (c) 2002, Richard Clamp. All Rights Reserved. This module is
free software. It may be used, redistributed and/or modified under the
same terms as Perl itself.
