X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/d6fd2b02d50b0bf989dc521c19ed6e9f2fbfb325..15a4d87479c14a0808c36a762bcd182890b84815:/lib/strict.pm

diff --git a/lib/strict.pm b/lib/strict.pm
index 042227f..8eed8bc 100644
--- a/lib/strict.pm
+++ b/lib/strict.pm
@@ -1,5 +1,57 @@
 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
@@ -37,19 +89,27 @@ use symbolic references (see L<perlref>).
     $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 "our" or 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;
     our $bar;			# Declares $bar in current package
@@ -65,45 +125,31 @@ exempted from this check.
 
 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<perlmodlib/Pragmatic Modules>.
 
+=head1 HISTORY
 
-=cut
-
-$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