mirror of
https://git.savannah.gnu.org/git/parallel.git
synced 2024-11-23 06:27:55 +00:00
131 lines
3.5 KiB
Perl
131 lines
3.5 KiB
Perl
package constant;
|
|
use 5.005;
|
|
use strict;
|
|
use warnings::register;
|
|
|
|
use vars qw($VERSION %declared);
|
|
$VERSION = '1.17';
|
|
|
|
#=======================================================================
|
|
|
|
# Some names are evil choices.
|
|
my %keywords = map +($_, 1), qw{ BEGIN INIT CHECK END DESTROY AUTOLOAD };
|
|
$keywords{UNITCHECK}++ if $] > 5.009;
|
|
|
|
my %forced_into_main = map +($_, 1),
|
|
qw{ STDIN STDOUT STDERR ARGV ARGVOUT ENV INC SIG };
|
|
|
|
my %forbidden = (%keywords, %forced_into_main);
|
|
|
|
#=======================================================================
|
|
# import() - import symbols into user's namespace
|
|
#
|
|
# What we actually do is define a function in the caller's namespace
|
|
# which returns the value. The function we create will normally
|
|
# be inlined as a constant, thereby avoiding further sub calling
|
|
# overhead.
|
|
#=======================================================================
|
|
sub import {
|
|
my $class = shift;
|
|
return unless @_; # Ignore 'use constant;'
|
|
my $constants;
|
|
my $multiple = ref $_[0];
|
|
my $pkg = caller;
|
|
my $symtab;
|
|
my $str_end = $] >= 5.006 ? "\\z" : "\\Z";
|
|
|
|
if ($] > 5.009002) {
|
|
no strict 'refs';
|
|
$symtab = \%{$pkg . '::'};
|
|
};
|
|
|
|
if ( $multiple ) {
|
|
if (ref $_[0] ne 'HASH') {
|
|
require Carp;
|
|
Carp::croak("Invalid reference type '".ref(shift)."' not 'HASH'");
|
|
}
|
|
$constants = shift;
|
|
} else {
|
|
$constants->{+shift} = undef;
|
|
}
|
|
|
|
foreach my $name ( keys %$constants ) {
|
|
unless (defined $name) {
|
|
require Carp;
|
|
Carp::croak("Can't use undef as constant name");
|
|
}
|
|
|
|
# Normal constant name
|
|
if ($name =~ /^_?[^\W_0-9]\w*$str_end/ and !$forbidden{$name}) {
|
|
# Everything is okay
|
|
|
|
# Name forced into main, but we're not in main. Fatal.
|
|
} elsif ($forced_into_main{$name} and $pkg ne 'main') {
|
|
require Carp;
|
|
Carp::croak("Constant name '$name' is forced into main::");
|
|
|
|
# Starts with double underscore. Fatal.
|
|
} elsif ($name =~ /^__/) {
|
|
require Carp;
|
|
Carp::croak("Constant name '$name' begins with '__'");
|
|
|
|
# Maybe the name is tolerable
|
|
} elsif ($name =~ /^[A-Za-z_]\w*$str_end/) {
|
|
# Then we'll warn only if you've asked for warnings
|
|
if (warnings::enabled()) {
|
|
if ($keywords{$name}) {
|
|
warnings::warn("Constant name '$name' is a Perl keyword");
|
|
} elsif ($forced_into_main{$name}) {
|
|
warnings::warn("Constant name '$name' is " .
|
|
"forced into package main::");
|
|
}
|
|
}
|
|
|
|
# Looks like a boolean
|
|
# use constant FRED == fred;
|
|
} elsif ($name =~ /^[01]?$str_end/) {
|
|
require Carp;
|
|
if (@_) {
|
|
Carp::croak("Constant name '$name' is invalid");
|
|
} else {
|
|
Carp::croak("Constant name looks like boolean value");
|
|
}
|
|
|
|
} else {
|
|
# Must have bad characters
|
|
require Carp;
|
|
Carp::croak("Constant name '$name' has invalid characters");
|
|
}
|
|
|
|
{
|
|
no strict 'refs';
|
|
my $full_name = "${pkg}::$name";
|
|
$declared{$full_name}++;
|
|
if ($multiple || @_ == 1) {
|
|
my $scalar = $multiple ? $constants->{$name} : $_[0];
|
|
if ($symtab && !exists $symtab->{$name}) {
|
|
# No typeglob yet, so we can use a reference as space-
|
|
# efficient proxy for a constant subroutine
|
|
# The check in Perl_ck_rvconst knows that inlinable
|
|
# constants from cv_const_sv are read only. So we have to:
|
|
Internals::SvREADONLY($scalar, 1);
|
|
$symtab->{$name} = \$scalar;
|
|
mro::method_changed_in($pkg);
|
|
} else {
|
|
*$full_name = sub () { $scalar };
|
|
}
|
|
} elsif (@_) {
|
|
my @list = @_;
|
|
*$full_name = sub () { @list };
|
|
} else {
|
|
*$full_name = sub () { };
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
1;
|
|
|
|
__END__
|
|
|