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On 2020-06-23 4:42 AM (-4), jr wrote:
> Cousin Ricky <ric### [at] yahoo com> wrote:
>> ...
>> - Once *any* identifier is declared, it cannot be reused as a macro
>> name.
>
> maybe I misunderstand. the following works on alpha.10064268.unofficial
>
> -----<snip>-----
> #version 3.8;
>
> global_settings {assumed_gamma 1}
>
> #declare A = 0;
>
> #undef A
>
> #macro A(b_)
> b_
> #end
>
> #declare B = A(1);
>
> #debug concat("B = ",str(B,0,0),"\n")
> -----<snip>-----
Of course you can reuse any identifier after you undefine it. But why
should you have to go through such nonsense?
> (if you remove the '#undef', ie try to create macro with same name while the
> identifier still _is_in_use_, error "expected undeclared identifier" occurs.
> which is as it should be, aiui)
No. It. Shouldn't.
What if the macro was defined in an include file written by someone
else? If the user declares A, they obviously have no need for macro A,
so why should they have to worry about whether a macro by that name
already exists?
But this is less serious an issue; the fact remains that if you declare
a *local* variable with the same name as a macro, the scene will not
parse. This means that anyone who writes a macro must make sure they do
not use local variables with the same name as a macro in any other
include file--even include files written by total strangers. The same
goes for function formal parameters.
This TOTALLY 100% defeats the purpose of local variables and formal
parameters! In order to write a robust POV include file, you must
essentially read the mind of every POVer on the planet.
This is why I complain about scope leakage. As far as I'm concerned,
the only acceptable level of scope leakage is ZERO.
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