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package source::encoding;
use v5.40;
our $VERSION = '0.01';
our $ascii_hint_bits = 0x00000010;
sub import {
unimport(); # Get rid of any 'use utf8'
my (undef, $arg) = @_;
if ($arg eq 'utf8') {
require utf8;
utf8->import;
return;
}
elsif ($arg eq 'ascii') {
$^H |= $ascii_hint_bits;
return;
}
die "Bad argument for source::encoding: '$arg'";
}
sub unimport {
$^H &= ~$ascii_hint_bits;
utf8->unimport;
}
1;
__END__
=head1 NAME
source::encoding -- Declare Perl source code encoding
=head1 SYNOPSIS
use source::encoding 'ascii';
use source::encoding 'utf8';
no source::encoding;
=head1 DESCRIPTION
These days, Perl code either generally contains only ASCII characters with
C<\x{}> and similar escapes to represent non-ASCII, or C<S<use utf8>> is used
to indicate that the source code itself contains characters encoded as UTF-8.
That means that a character in the source code not meeting these criteria is
often a typographical error. This pragma is used to tell Perl to raise an
error when this happens.
S<C<use source::encoding 'utf8'>> is a synonym for S<C<use utf8>>. They may
be used interchangeably.
S<C<use source::encoding 'ascii'>> turns off any UTF-8 expectations, and
raises a fatal error if any character within its scope in the input source
code is not ASCII (or ASCII-equivalent on EBCDIC systems).
S<C<no source::encoding>> turns off any UTF-8/ASCII expectations for the
remainder of its scope. The meaning of non-ASCII characters is then
undefined.
S<C<use source::encoding 'ascii'>> is automatically enabled within the
lexical scope of a S<C<use v5.41.0>> or higher.
=head1 SEE ALSO
L<utf8>
=cut
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