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package Devel::Hints;
$VERSION = '0.21';
use strict;
use vars qw($VERSION @ISA @EXPORT_OK %EXPORT_TAGS);
use 5.006;
require Exporter;
require DynaLoader;
@ISA = qw( Exporter DynaLoader );
%EXPORT_TAGS = ( all => \@EXPORT_OK );
@EXPORT_OK = ( qw(
cop_label
cop_stash cop_stashpv
cop_file cop_filegv
cop_seq
cop_arybase
cop_line
cop_warnings
cop_io
),
);
__PACKAGE__->bootstrap($VERSION);
1;
__END__
=encoding utf8
=head1 NAME
Devel::Hints - Access compile-time hints at runtime
=head1 VERSION
This document describes version 0.21 of Devel::Hints, released
November 10, 2010.
=head1 SYNOPSIS
use Devel::Hints ':all';
LABEL:
print cop_label(); # 'LABEL'
# cop_label is only settable on Perl 5.8 or below
cop_label(0 => 'FOO'); # "goto FOO;" is valid after this point!
print cop_file(); # same as __FILE__
print cop_filegv(); # same as \$::{'_<' . __FILE__}
print cop_stashpv(); # same as __PACKAGE__
print cop_stash(); # same as \%{__PACKAGE__ . '::'}
print cop_seq(); # an integer
print cop_arybase(); # same as $[
print cop_line(); # same as __LINE__
# cop_warnings() is only available to Perl 5.8 or below
use warnings;
print cop_warnings(); # same as compile-time ${^WARNING_BITS}
# cop_io() is only available to Perl 5.7 and Perl 5.8
use open IO => ':utf8';
print cop_io(); # same as compile-time ${^OPEN}
{
use IO => ':raw';
print cop_io(1); # access one uplevel; still ":utf8\0:utf8"
}
=head1 DESCRIPTION
This module exports the C<cop> (code operator) struct as individual
functions; callers can call them to find out the lexical-scoped hints
that its block (or statement) is compiled under.
No functions are exported by default. Each function may take an
optional positive integer as argument, indicating how many blocks
it should walk upward to obtain the C<cop> members.
Functions can also take another optional argument, which (if specified)
I<becomes the new value> for the hint, affecting the current statement
or block's behaviour.
On perl 5.10 or greater, the first argument to these functions can also be a
coderef. In that case, they return the value for the first statement in the
coderef's body, and if an argument is passed, they set the value for the entire
coderef body. C<cop_line> and C<cop_file> are slightly special here - #line
directives within the coderef will still be respected, and the line will be
offset by the correct amount within the sub.
=head1 FUNCTIONS
=over 4
=item cop_label
Label for the current construct.
=item cop_file
File name for the current source file.
=item cop_filegv
Glob reference to the current source filehandle.
=item cop_stashpv
The current package name.
=item cop_stash
Hash reference to the current symbol table.
=item cop_seq
Parse sequencial number.
=item cop_arybase
Array base the calling line was compiled with.
=item cop_line
The line number.
=item cop_warnings
Lexical warnings bitmask, a.k.a. C<${^WARNING_BITS}>. If no lexical
warnings are in effect, returns the global warning flags as an integer.
=item cop_io
Lexical IO defaults, a.k.a. C<${^OPEN}>. If no lexical IO layers
are in effect, an empty string is returned. Always returns C<undef>
under pre-5.7 versions of Perl.
=back
=head1 ACKNOWLEDGMENTS
Thanks to Rafael Garcia-Suarez for demonstrating how to do this with
the elegant B<Inline::C> code on p5p, which I adapted to this
less elegant XS implementation.
=head1 AUTHORS
唐鳳 E<lt>cpan@audreyt.orgE<gt>
=head1 CC0 1.0 Universal
To the extent possible under law, 唐鳳 has waived all copyright and related
or neighboring rights to Devel-Hints.
This work is published from Taiwan.
L<http://creativecommons.org/publicdomain/zero/1.0>
=cut