Installing chained methods

I'd like to install one or a few methods into a given slot. If no method already exists in a given slot then my copy should be directly copied. If I need a second or more method to then I need to have a stub method call each of the real methods. While the actual code for this is pretty simple I think this far too messy for something in a database application and I don't want to force volunteer programmers to cope with this.

This is intended to be used in an application using the Alzabo OR mapping system and in this case I need to call both an auditing and versioning method when the pre_insert event occurs. For one method call I'd just copy *pkg::pre_insert = *auditing_pre_insert and leave it at that but since it isn't that trivial I don't feel comfortable doing this right in the application.

I'm hoping someone here knows of a nice module for this so I can use that instead. Suggestions?

if (*{"GreenPartyDB::Database::${table}::${hook}"}{CODE}) {
    my $old = *{"GreenPartyDB::Database::${table}::${hook}"}{CODE};
    my $new = *{__PACKAGE__."::${prefix}${hook}"}{CODE}
    *{"GreenPartyDB::Database::${table}::${hook}"} =
    sub { $_[0]->$old( @_[ 1 .. $#_ ] );
          $_[0]->$new( @_[ 1 .. $#_ ] ); };
} else {
    *{"GreenPartyDB::Database::${table}::${hook}"} =
        *{__PACKAGE__."::${prefix}${hook}"}{CODE};
}
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Re: Installing chained methods (Hook::*?) by Aristotle (Chancellor) on Apr 21, 2003 at 02:33 UTC
Hook::WrapSub? Hook::PrePostCall? Hook::LexWrap? One of these will probably suit your tastes. Makeshifts last the longest.	[reply]
Re: Re: Installing chained methods by diotalevi (Canon) on Apr 21, 2003 at 03:42 UTC
Nothing in the Hook:: ~~class~~ namespace does the right thing here (including Class::Hook). Thank you though. All the Hook:: modules assume that the method already exists and I'm looking at it from the other direction - initially the method doesn't exist and the code just installs it somewhat like Exporter. Oh well - absent any good suggestions (after waiting a while) I'll just write the darn thing and upload it. Thank you for suggesting Hook:: though - that search keyword didn't occur to me.	[reply]
Re^3: Installing chained methods (wrap a stub?) by Aristotle (Chancellor) on Apr 21, 2003 at 03:55 UTC
Aha, I see. Maybe like so? `use Hook::WrapSubs; do { no strict 'refs'; {"GreenPartyDB::Database::${table}::${hook}"} = sub {}; } unless UNIVERSAL::can("GreenPartyDB::Database::${table}", $hook) wrap_subs( "GreenPartyDB::Database::${table}::${hook}", UNIVERSAL::can(__PACKAGE__."::${prefix}", $hook), );` [download] Note that using `UNIVERSAL::can()` will respect inherited methods, which is not unlikely to be better than what you started out with (or may be not, of course - your call). Makeshifts last the longest.*	[reply] [d/l]
Re: Re^3: Installing chained methods (wrap a stub?) by diotalevi (Canon) on Apr 22, 2003 at 03:36 UTC
Re^5: Installing chained methods (ambiguous name) by Aristotle (Chancellor) on Apr 22, 2003 at 14:01 UTC
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Installing chained methods

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