| 1 | package overloading; |
| 2 | use warnings; |
| 3 | |
| 4 | our $VERSION = '0.02'; |
| 5 | |
| 6 | my $HINT_NO_AMAGIC = 0x01000000; # see perl.h |
| 7 | |
| 8 | require 5.010001; |
| 9 | |
| 10 | sub _ops_to_nums { |
| 11 | require overload::numbers; |
| 12 | |
| 13 | map { exists $overload::numbers::names{"($_"} |
| 14 | ? $overload::numbers::names{"($_"} |
| 15 | : do { require Carp; Carp::croak("'$_' is not a valid overload") } |
| 16 | } @_; |
| 17 | } |
| 18 | |
| 19 | sub import { |
| 20 | my ( $class, @ops ) = @_; |
| 21 | |
| 22 | if ( @ops ) { |
| 23 | if ( $^H{overloading} ) { |
| 24 | vec($^H{overloading} , $_, 1) = 0 for _ops_to_nums(@ops); |
| 25 | } |
| 26 | |
| 27 | if ( $^H{overloading} !~ /[^\0]/ ) { |
| 28 | delete $^H{overloading}; |
| 29 | $^H &= ~$HINT_NO_AMAGIC; |
| 30 | } |
| 31 | } else { |
| 32 | delete $^H{overloading}; |
| 33 | $^H &= ~$HINT_NO_AMAGIC; |
| 34 | } |
| 35 | } |
| 36 | |
| 37 | sub unimport { |
| 38 | my ( $class, @ops ) = @_; |
| 39 | |
| 40 | if ( exists $^H{overloading} or not $^H & $HINT_NO_AMAGIC ) { |
| 41 | if ( @ops ) { |
| 42 | vec($^H{overloading} ||= '', $_, 1) = 1 for _ops_to_nums(@ops); |
| 43 | } else { |
| 44 | delete $^H{overloading}; |
| 45 | } |
| 46 | } |
| 47 | |
| 48 | $^H |= $HINT_NO_AMAGIC; |
| 49 | } |
| 50 | |
| 51 | 1; |
| 52 | __END__ |
| 53 | |
| 54 | =head1 NAME |
| 55 | |
| 56 | overloading - perl pragma to lexically control overloading |
| 57 | |
| 58 | =head1 SYNOPSIS |
| 59 | |
| 60 | { |
| 61 | no overloading; |
| 62 | my $str = "$object"; # doesn't call stringification overload |
| 63 | } |
| 64 | |
| 65 | # it's lexical, so this stringifies: |
| 66 | warn "$object"; |
| 67 | |
| 68 | # it can be enabled per op |
| 69 | no overloading qw(""); |
| 70 | warn "$object"; |
| 71 | |
| 72 | # and also reenabled |
| 73 | use overloading; |
| 74 | |
| 75 | =head1 DESCRIPTION |
| 76 | |
| 77 | This pragma allows you to lexically disable or enable overloading. |
| 78 | |
| 79 | =over 6 |
| 80 | |
| 81 | =item C<no overloading> |
| 82 | |
| 83 | Disables overloading entirely in the current lexical scope. |
| 84 | |
| 85 | =item C<no overloading @ops> |
| 86 | |
| 87 | Disables only specific overloads in the current lexical scope. |
| 88 | |
| 89 | =item C<use overloading> |
| 90 | |
| 91 | Reenables overloading in the current lexical scope. |
| 92 | |
| 93 | =item C<use overloading @ops> |
| 94 | |
| 95 | Reenables overloading only for specific ops in the current lexical scope. |
| 96 | |
| 97 | =back |
| 98 | |
| 99 | =cut |