package strict;
+$strict::VERSION = "1.08";
+
+# Verify that we're called correctly so that strictures will work.
+unless ( __FILE__ =~ /(^|[\/\\])\Q${\__PACKAGE__}\E\.pmc?$/ ) {
+ # Can't use Carp, since Carp uses us!
+ my (undef, $f, $l) = caller;
+ die("Incorrect use of pragma '${\__PACKAGE__}' at $f line $l.\n");
+}
+
+my %bitmask = (
+refs => 0x00000002,
+subs => 0x00000200,
+vars => 0x00000400
+);
+my %explicit_bitmask = (
+refs => 0x00000020,
+subs => 0x00000040,
+vars => 0x00000080
+);
+
+sub bits {
+ my $bits = 0;
+ my @wrong;
+ foreach my $s (@_) {
+ if (exists $bitmask{$s}) {
+ $^H |= $explicit_bitmask{$s};
+ }
+ else { push @wrong, $s };
+ $bits |= $bitmask{$s} || 0;
+ }
+ if (@wrong) {
+ require Carp;
+ Carp::croak("Unknown 'strict' tag(s) '@wrong'");
+ }
+ $bits;
+}
+
+my @default_bits = qw(refs subs vars);
+
+sub import {
+ shift;
+ $^H |= bits(@_ ? @_ : @default_bits);
+}
+
+sub unimport {
+ shift;
+ $^H &= ~ bits(@_ ? @_ : @default_bits);
+}
+
+1;
+__END__
+
=head1 NAME
strict - Perl pragma to restrict unsafe constructs
print $$ref; # ok
$ref = "foo";
print $$ref; # runtime error; normally ok
+ $file = "STDOUT";
+ print $file "Hi!"; # error; note: no comma after $file
+
+There is one exception to this rule:
+
+ $bar = \&{'foo'};
+ &$bar;
+
+is allowed so that C<goto &$AUTOLOAD> would not break under stricture.
+
=item C<strict vars>
-This generates a compile-time error if you access a variable that wasn't
-declared via C<use vars>,
-localized via C<my()> or wasn't fully qualified. Because this is to avoid
-variable suicide problems and subtle dynamic scoping issues, a merely
-local() variable isn't good enough. See L<perlfunc/my> and
-L<perlfunc/local>.
+This generates a compile-time error if you access a variable that was
+neither explicitly declared (using any of C<my>, C<our>, C<state>, or C<use
+vars>) nor fully qualified. (Because this is to avoid variable suicide
+problems and subtle dynamic scoping issues, a merely C<local> variable isn't
+good enough.) See L<perlfunc/my>, L<perlfunc/our>, L<perlfunc/state>,
+L<perlfunc/local>, and L<vars>.
use strict 'vars';
$X::foo = 1; # ok, fully qualified
my $foo = 10; # ok, my() var
- local $foo = 9; # blows up
+ local $baz = 9; # blows up, $baz not declared before
package Cinna;
- use vars qw/ $bar /; # Declares $bar in current package
+ our $bar; # Declares $bar in current package
$bar = 'HgS'; # ok, global declared via pragma
The local() generated a compile-time error because you just touched a global
name without fully qualifying it.
+Because of their special use by sort(), the variables $a and $b are
+exempted from this check.
+
=item C<strict subs>
This disables the poetry optimization, generating a compile-time error if
you try to use a bareword identifier that's not a subroutine, unless it
-appears in curly braces or on the left hand side of the "=E<gt>" symbol.
-
+is a simple identifier (no colons) and that it appears in curly braces or
+on the left hand side of the C<< => >> symbol.
use strict 'subs';
- $SIG{PIPE} = Plumber; # blows up
- $SIG{PIPE} = "Plumber"; # just fine: bareword in curlies always ok
- $SIG{PIPE} = \&Plumber; # preferred form
-
-
+ $SIG{PIPE} = Plumber; # blows up
+ $SIG{PIPE} = "Plumber"; # fine: quoted string is always ok
+ $SIG{PIPE} = \&Plumber; # preferred form
=back
-See L<perlmod/Pragmatic Modules>.
-
+See L<perlmodlib/Pragmatic Modules>.
-=cut
-
-$strict::VERSION = "1.01";
+=head1 HISTORY
-my %bitmask = (
-refs => 0x00000002,
-subs => 0x00000200,
-vars => 0x00000400
-);
-
-$strict::VERSION = "1.01";
-
-my %bitmask = (
-refs => 0x00000002,
-subs => 0x00000200,
-vars => 0x00000400
-);
+C<strict 'subs'>, with Perl 5.6.1, erroneously permitted to use an unquoted
+compound identifier (e.g. C<Foo::Bar>) as a hash key (before C<< => >> or
+inside curlies), but without forcing it always to a literal string.
-sub bits {
- my $bits = 0;
- foreach my $s (@_){ $bits |= $bitmask{$s} || 0; };
- $bits;
-}
+Starting with Perl 5.8.1 strict is strict about its restrictions:
+if unknown restrictions are used, the strict pragma will abort with
-sub import {
- shift;
- $^H |= bits(@_ ? @_ : qw(refs subs vars));
-}
+ Unknown 'strict' tag(s) '...'
-sub unimport {
- shift;
- $^H &= ~ bits(@_ ? @_ : qw(refs subs vars));
-}
+As of version 1.04 (Perl 5.10), strict verifies that it is used as
+"strict" to avoid the dreaded Strict trap on case insensitive file
+systems.
-1;
+=cut
https://perl5.git.perl.org / perl5.git / blobdiff