| 1 | package caller; |
| 2 | use vars qw($VERSION); |
| 3 | $VERSION = "1.0"; |
| 4 | |
| 5 | =head1 NAME |
| 6 | |
| 7 | caller - inherit pragmatic attributes from the context of the caller |
| 8 | |
| 9 | =head1 SYNOPSIS |
| 10 | |
| 11 | use caller qw(encoding); |
| 12 | |
| 13 | =head1 DESCRIPTION |
| 14 | |
| 15 | This pragma allows a module to inherit some attributes from the |
| 16 | context which loaded it. |
| 17 | |
| 18 | Inheriting attributes takes place at compile time; this means |
| 19 | only attributes that are visible in the calling context at compile |
| 20 | time will be propagated. |
| 21 | |
| 22 | Currently, the only supported attribute is C<encoding>. |
| 23 | |
| 24 | =over |
| 25 | |
| 26 | =item encoding |
| 27 | |
| 28 | Indicates that the character set encoding of the caller's context |
| 29 | must be inherited. This can be used to inherit the C<use utf8> |
| 30 | setting in the calling context. |
| 31 | |
| 32 | =back |
| 33 | |
| 34 | =cut |
| 35 | |
| 36 | my %bitmask = ( |
| 37 | # only HINT_UTF8 supported for now |
| 38 | encoding => 0x8 |
| 39 | ); |
| 40 | |
| 41 | sub bits { |
| 42 | my $bits = 0; |
| 43 | for my $s (@_) { $bits |= $bitmask{$s} || 0; }; |
| 44 | $bits; |
| 45 | } |
| 46 | |
| 47 | sub import { |
| 48 | shift; |
| 49 | my @cxt = caller(3); |
| 50 | if (@cxt and $cxt[7]) { # was our parent require-d? |
| 51 | $^H |= bits(@_) & $cxt[8]; |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | sub unimport { |
| 56 | # noop currently |
| 57 | } |
| 58 | |
| 59 | 1; |