----------------------------------------------------------------------------- | Want v0.23 - Robin Houston, 2014-03-24 ----------------------------------------------------------------------------- For full documentation, see the POD included with the module. Below is a brief extract of the documentation, to give you an idea of what this module does. It requires Perl version 5.6 or later. NAME Want - Implement the `want' command SYNOPSIS use Want; sub foo :lvalue { if (want(qw'LVALUE ASSIGN')) { print "We have been assigned ", want('ASSIGN'); lnoreturn; } elsif (want('LIST')) { rreturn (1, 2, 3); } elsif (want('BOOL')) { rreturn 0; } elsif (want(qw'SCALAR !REF')) { rreturn 23; } elsif (want('HASH')) { rreturn { foo => 17, bar => 23 }; } return } DESCRIPTION This module generalises the mechanism of the wantarray function, allowing a function to determine in some detail how its return value is going to be immediately used. ... EXAMPLES use Carp 'croak'; use Want 'howmany'; sub numbers { my $count = howmany(); croak("Can't make an infinite list") if !defined($count); return (1..$count); } my ($one, $two, $three) = numbers(); use Want 'want'; sub pi () { if (want('ARRAY')) { return [3, 1, 4, 1, 5, 9]; } elsif (want('LIST')) { return (3, 1, 4, 1, 5, 9); } else { return 3; } } print pi->[2]; # prints 4 print ((pi)[3]); # prints 1 use Want; use strict; sub backstr :lvalue { if (want(qw'LVALUE ASSIGN')) { my ($a) = want('ASSIGN'); $_[0] = reverse $a; lnoreturn; } elsif (want('RVALUE')) { rreturn scalar reverse $_[0]; } else { carp("Not in ASSIGN context"); } return } print "foo -> ", backstr("foo"), "\n"; # foo -> oof backstr(my $robin) = "nibor"; print "\$robin is now $robin\n"; # $robin is now robin AUTHOR Robin Houston, Thanks to Damian Conway for encouragement and good suggestions, and to Father Chrysostomos and Matthew Horsfall for patches. SEE ALSO o the wantarray entry in the perlfunc manpage o Perl6 RFC 21, by Damian Conway. http://dev.perl.org/rfc/21.html COPYRIGHT Copyright (c) 2001-2012, Robin Houston. All Rights Reserved. This module is free software. It may be used, redistributed and/or modified under the same terms as Perl itself.