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- Subject: Re: Metatables
- From: "James Hearn" <james.hearn@<a href="/cgi-bin/echo.cgi?byu.edu">...</a>>
- Date: Wed, 27 Feb 2002 18:18:03 -0600
> >I'm using Lua to replace a scripting language (which I'll call FOO)
> Perhaps FOO == awk ?
> >My problem is that I can't have both.
> Yes, you can, but it's not so simple.
> Try this: define the index method for globals to return a special kind
> of proxy table, one for which methods are defined to handle arithmetic and
> indexing. When you create these proxy tables in the index method for the
> global table, store the name of the variable. Later, when the value is used
> as a number, the variable becomes an ordinary global variable with a number
> value (you do this in the getglobal method for globals, and looking at the
> metatable of the value to see whether it is a proxy table). Similarly when
> the value is used as a table, but in this case it is easier because you
> only have to use the index method for the proxy. Again, you can then "convert"
> the proxy into a true value. Or you might keep both options (and then you'll
> be cloning the behaviour of awk, which allows a=0 and a=1 simultaneously).
> Sorry for the long, text-only explanation, and no code...
> Anyway, I hope it helps.
If I understand, this is a way to "delay" deciding what the value of 'a' is
until it's used in an expression? I've done a similar thing in the past with
NebLUA. It worked pretty well within the scope of that project.