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Packages, Modules and Classes

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Stevan Little
September 6, 2005 11:05
Packages, Modules and Classes
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Hey all,

I recently added Package and Module into the MetaModel (2.0) so that

    Package is an Object
    Module is a Package
    Class is a Module

as mentioned here 
Currently Packages have names and Modules add version and authority 
information, but I have nothing yet in place to represent package 
symbol tables. Which brings me to my questions.

I assume that each symbol table entry has the following slots; SCALAR, 
ARRAY, HASH, SUB, METH. I base this off the AUTO* hooks described in 
S10. I assume too that the METH slot is only valid for Classes, and not 
appropriate for Packages and Modules.

This would mean that given this code:

   package Foo;
   our $baz;
   sub bar { ... }

%Foo::{'bar'}{SUB} is a ref to the &bar sub, and %Foo::{'baz'}{SCALAR} 
is a ref to the scalar $baz. The same, I would assume, would apply for 
Modules, so that:

   module Foo;
   our $baz;
   sub bar { ... }

is pretty much interchangable with the first example. But I think it's 
a little trickier when we get to Classes. Given this code:

   class Foo;
   our $baz;
   sub bar { ... }

I would expect it to behave just as it does for a Package or Module. 
But when we start to introduce methods and attributes, I am unsure of 
how things will work.

   class Foo;
   has $.baz;
   method bar { ... }

Can I get to $.baz? If I can, what will I get?

I expect that %Foo::{'bar'}{METH} will give me a method ref, but what 
happens when I try to store something in it? Does that perform some 
kind of meta-model actions (Foo.meta.change_method(...) or somesuch)? 
What if I delete the symbol table entry, what happens then (more 



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