More robust yacc/bison failure output handling.

[p5sagit/p5-mst-13.2.git] / lib / Symbol.pm

diff --git a/lib/Symbol.pm b/lib/Symbol.pm
index e40ae7b..5ed6b26 100644 (file)
--- a/lib/Symbol.pm
+++ b/lib/Symbol.pm
@@ -23,6 +23,15 @@ Symbol - manipulate Perl symbols and their names
     print qualify(\*x), "\n";              # returns \*x
     print qualify(\*x, "FOO"), "\n";       # returns \*x
 
+    use strict refs;
+    print { qualify_to_ref $fh } "foo!\n";
+    $ref = qualify_to_ref $name, $pkg;
+
+    use Symbol qw(delete_package);
+    delete_package('Foo::Bar');
+    print "deleted\n" unless exists $Foo::{'Bar::'};
+
+
 =head1 DESCRIPTION
 
 C<Symbol::gensym> creates an anonymous glob and returns a reference
@@ -44,14 +53,24 @@ Qualification applies only to symbol names (strings).  References are
 left unchanged under the assumption that they are glob references,
 which are qualified by their nature.
 
+C<Symbol::qualify_to_ref> is just like C<Symbol::qualify> except that it
+returns a glob ref rather than a symbol name, so you can use the result
+even if C<use strict 'refs'> is in effect.
+
+C<Symbol::delete_package> wipes out a whole package namespace.  Note
+this routine is not exported by default--you may want to import it
+explicitly.
+
 =cut
 
 BEGIN { require 5.002; }
 
 require Exporter;
 @ISA = qw(Exporter);
+@EXPORT = qw(gensym ungensym qualify qualify_to_ref);
+@EXPORT_OK = qw(delete_package);
 
-@EXPORT = qw(gensym ungensym qualify);
+$VERSION = 1.02;
 
 my $genpkg = "Symbol::";
 my $genseq = 0;
@@ -88,4 +107,33 @@ sub qualify ($;$) {
     $name;
 }
 
+sub qualify_to_ref ($;$) {
+    return \*{ qualify $_[0], @_ > 1 ? $_[1] : caller };
+}
+
+#
+# of Safe.pm lineage
+#
+sub delete_package ($) {
+    my $pkg = shift;
+
+    # expand to full symbol table name if needed
+
+    unless ($pkg =~ /^main::.*::$/) {
+        $pkg = "main$pkg"      if      $pkg =~ /^::/;
+        $pkg = "main::$pkg"    unless  $pkg =~ /^main::/;
+        $pkg .= '::'           unless  $pkg =~ /::$/;
+    }
+
+    my($stem, $leaf) = $pkg =~ m/(.*::)(\w+::)$/;
+    my $stem_symtab = *{$stem}{HASH};
+    return unless defined $stem_symtab and exists $stem_symtab->{$leaf};
+
+    my $leaf_glob   = $stem_symtab->{$leaf};
+    my $leaf_symtab = *{$leaf_glob}{HASH};
+
+    %$leaf_symtab = ();
+    delete $stem_symtab->{$leaf};
+}
+
 1;