[San-Diego-pm] Deleting package from memory

[Daniel Risse]

Hello,

This is to follow up to what Urivan was discussing last night.  I looked 
and Symbol does in fact define the delete_package() function.  There is 
a warning in the documentation regarding it though:

> Symbol::delete_package is a bit too powerful. It undefines every 
> symbol that
> lives in the specified package. Since perl, for performance reasons, 
> does not
> perform a symbol table lookup each time a function is called or a global
> variable is accessed, some code that has already been loaded and that 
> makes use
> of symbols in package Foo may stop working after you delete Foo, even if
> you reload the Foo module afterwards.

There is also something that strikes me as a bit wrong about loading an 
additional module to assist unloading other modules.  The function could 
be copied and modified to also clear out the %INC entry for the module.

> 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};
>
>
>     # free all the symbols in the package
>
>     my $leaf_symtab = *{$stem_symtab->{$leaf}}{HASH};
>     foreach my $name (keys %$leaf_symtab) {
>         undef *{$pkg . $name};
>     }
>
>     # delete the symbol table
>
>     %$leaf_symtab = ();
>     delete $stem_symtab->{$leaf};
> }

Dan