100 lines
1.8 KiB
Perl
100 lines
1.8 KiB
Perl
package overloading;
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use warnings;
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our $VERSION = '0.02';
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my $HINT_NO_AMAGIC = 0x01000000; # see perl.h
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require 5.010001;
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sub _ops_to_nums {
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require overload::numbers;
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map { exists $overload::numbers::names{"($_"}
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? $overload::numbers::names{"($_"}
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: do { require Carp; Carp::croak("'$_' is not a valid overload") }
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} @_;
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}
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sub import {
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my ( $class, @ops ) = @_;
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if ( @ops ) {
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if ( $^H{overloading} ) {
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vec($^H{overloading} , $_, 1) = 0 for _ops_to_nums(@ops);
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}
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if ( $^H{overloading} !~ /[^\0]/ ) {
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delete $^H{overloading};
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$^H &= ~$HINT_NO_AMAGIC;
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}
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} else {
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delete $^H{overloading};
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$^H &= ~$HINT_NO_AMAGIC;
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}
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}
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sub unimport {
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my ( $class, @ops ) = @_;
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if ( exists $^H{overloading} or not $^H & $HINT_NO_AMAGIC ) {
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if ( @ops ) {
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vec($^H{overloading} ||= '', $_, 1) = 1 for _ops_to_nums(@ops);
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} else {
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delete $^H{overloading};
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}
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}
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$^H |= $HINT_NO_AMAGIC;
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}
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1;
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__END__
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=head1 NAME
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overloading - perl pragma to lexically control overloading
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=head1 SYNOPSIS
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{
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no overloading;
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my $str = "$object"; # doesn't call stringification overload
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}
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# it's lexical, so this stringifies:
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warn "$object";
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# it can be enabled per op
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no overloading qw("");
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warn "$object";
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# and also reenabled
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use overloading;
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=head1 DESCRIPTION
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This pragma allows you to lexically disable or enable overloading.
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=over 6
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=item C<no overloading>
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Disables overloading entirely in the current lexical scope.
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=item C<no overloading @ops>
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Disables only specific overloads in the current lexical scope.
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=item C<use overloading>
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Reenables overloading in the current lexical scope.
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=item C<use overloading @ops>
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Reenables overloading only for specific ops in the current lexical scope.
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=back
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=cut
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