X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2Fstrict.pm;h=d1479ed865ee1dd4c627f6d08ec90728f628c70c;hb=c9bca74aca217023baf0f921dcffaaa072a83cf3;hp=adaf47c720269081d9e07ead17988a8d40249e7e;hpb=a0d0e21ea6ea90a22318550944fe6cb09ae10cda;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/lib/strict.pm b/lib/strict.pm
index adaf47c..d1479ed 100644
--- a/lib/strict.pm
+++ b/lib/strict.pm
@@ -1,11 +1,23 @@
 package strict;
 
+$strict::VERSION = "1.02";
+
+my %bitmask = (
+refs => 0x00000002,
+subs => 0x00000200,
+vars => 0x00000400
+);
+
 sub bits {
     my $bits = 0;
-    foreach $sememe (@_) {
-	$bits |= 0x00000002 if $sememe eq 'refs';
-	$bits |= 0x00000200 if $sememe eq 'subs';
-	$bits |= 0x00000400 if $sememe eq 'vars';
+    my @wrong;
+    foreach my $s (@_) {
+	push @wrong, $s unless exists $bitmask{$s};
+        $bits |= $bitmask{$s} || 0;
+    }
+    if (@wrong) {
+        require Carp;
+        Carp::croak("Unknown 'strict' tag(s) '@wrong'");
     }
     $bits;
 }
@@ -21,3 +33,93 @@ sub unimport {
 }
 
 1;
+__END__
+
+=head1 NAME
+
+strict - Perl pragma to restrict unsafe constructs
+
+=head1 SYNOPSIS
+
+    use strict;
+
+    use strict "vars";
+    use strict "refs";
+    use strict "subs";
+
+    use strict;
+    no strict "vars";
+
+=head1 DESCRIPTION
+
+If no import list is supplied, all possible restrictions are assumed.
+(This is the safest mode to operate in, but is sometimes too strict for
+casual programming.)  Currently, there are three possible things to be
+strict about:  "subs", "vars", and "refs".
+
+=over 6
+
+=item C<strict refs>
+
+This generates a runtime error if you 
+use symbolic references (see L<perlref>).
+
+    use strict 'refs';
+    $ref = \$foo;
+    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 "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>.
+
+    use strict 'vars';
+    $X::foo = 1;	 # ok, fully qualified
+    my $foo = 10;	 # ok, my() var
+    local $foo = 9;	 # blows up
+
+    package Cinna;
+    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.
+
+
+    use strict 'subs';
+    $SIG{PIPE} = Plumber;   	# blows up
+    $SIG{PIPE} = "Plumber"; 	# just fine: bareword in curlies always ok
+    $SIG{PIPE} = \&Plumber; 	# preferred form
+
+
+
+=back
+
+See L<perlmodlib/Pragmatic Modules>.
+
+=cut