Re: Upvalue question
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- Subject: Re: Upvalue question
- From: "Magnus Lie Hetland" <mlh@...>
- Date: 2001年2月14日 21:16:41 +0100
> > Is it so that upvalues only "care" about functions?
>
> Yes.
>
>
> > But if that block is changed into a function, an error message occurs...
> >
> > "upvalue must be global or local to immediately outer scope"
>
> The message should be "... to immediately outer function".
Ah. I see. Actually, this works like normal variable lookup
at the point of the function definition, right? (I.e.
shadowing is in effect.)
This leaves me with just a couple of other questions: Firstly,
why can variables be local to the main chunk? As far as I can
see, there is no way to access them?
And secondly, why can inner functions refer to global variables
only when they aren't shadowed by a variable local to a
surrounding scope? Is this an implementation issue, or is it
simply assumed that users want to use the local ones, and
they can't without upvalues?
Both these issues seem a bit arbitrary to me, but I am sure
I'm missing something important :)
--
Magnus Lie Hetland (magnus at hetland dot org)
"Reality is what refuses to disappear when you stop
believing in it" -- Philip K. Dick