Re: FOR i ...
CChris wrote:
>
> Chris Bensler wrote:
> >
> > Would it break any code if i were simply allowed to exist after the end of
> > the
> > loop?
> >
> > for i = 1 to 2 do
> > end for
> > for i = i to 4 do
> > end for
> >
> > Chris Bensler
> > Code is Alchemy
>
> I don't think it would, but then Pete's proposal of allowing a predeclared
> integer
> i won't work (or will do with subtle side effects, which is worse).
> The parser will have to decide whether an existing i is a predeclared non loop
> variable - probably disallowed, cf CK -, a loop index at the same level -
> allowed
> and reusing that index - or a nesting loop index - disallowed -.
>
> As a result, the i defined last before ex.err is generated will be dumped
> there,
> whether the loop it belongs to was active or no longer is, with its last
> value.
> Not worse that the current state of things.
>
> This wouldn't add another construct to the language, but change the semantics
> of an existing one. Not my own preference, because _both_ semantics are useful
> to have.
>
> CChris
To re-iterate what I wrote on an entirely inappropriate subject, why is it not
possible/reasonable to simply say that if the for-loop variable is declared
prior to the loop then it is used - and remains in scope after the loop exits -
and if the variable does NOT exist then the behaviour is exactly as it is now
in that the variable is in scope only for the duration of the for-next loop.
This is consistent with C-style languages if you consider the loop to be a
procedure. This MIGHT break existing programs but only if written in a way
that uses the same variable name outside the loop as inside, with no relation
between them - a pretty poor way of writing code anyway, IMHO. I guess if you
tried to use a non-atomic variable you would have to raise an error but that
is right anyway.
AndyD
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