runtime variables and runtime attributes.

Koschei has asked for the wisdom of the Perl Monks concerning the following question:

Ok, Perl 5.8.0 introduces runtime application of variable attributes. All fine and dandy. However, I'd like to be able to pass variables in my attribute declarations. For example:

my $bar = 3; my Cat $foo : Legs($bar);

As perldelta (perl58delta for bleaders) says:

In particular, however, this allows variable attributes to be useful for "tie" interfaces, which was a deficiency of earlier releases.

So, how does one actually evaluate the $bar? MODIFY_SCALAR_ATTRIBUTES gets called with a string "Legs($bar)" and no hook into the appropriate namespace.

-- Iain, aka Koschei.

Comment on runtime variables and runtime attributes.

Replies are listed 'Best First'.
Re: runtime variables and runtime attributes. by IlyaM (Parson) on Jul 22, 2002 at 08:13 UTC
Not sure if it will work but you can try to get access to variables using Devel::LexAlias. OTOH after playing with attributes I decided for myself to do not use them because they have too many limitations (my favorite is that Perl insists that the entire attribute be on one line). -- Ilya Martynov (http://martynov.org/)	[reply]
Re: Re: runtime variables and runtime attributes. by Koschei (Monk) on Jul 25, 2002 at 01:56 UTC
Joyously, most of the modules required for LexAlias, and perhaps LexAlias itself, need patching to work on threaded Perl, so I'm afraid my investigations have been put on hold for a bit. The relevant authors are onto it though, so I expect things will be hunky dory LexAlias wise by the end of the week =) So, anyone for Poker? Yes, I could go and compile myself a non-threading Perl, but I'm on a P120 and it would take about the same time as for the new versions of PadWalker, Devel::Caller and so on to come out =) -- Iain, aka Koschei.	[reply]


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