[slang-users] debug: points where left on the stack

[Joerg Sommer]

Marko Mahnic <marko.mahnic at email.si> wrote:
> Joerg Sommer wrote:
>> "John E. Davis" <davis at space.mit.edu> wrote:
>> 
>>>Joerg Sommer <joerg at alea.gnuu.de> wrote:
>>>
>>>>do_check();
>>>>do_something();
>>>>if ( () )
>>>
>>>You should try to minimize the use of such constructs.
>> 
>> Why? Is a cool feature of slang.
>> 
> It is a cool feature but it makes the code harder to read,
> understand

ACK

> and mantain.

You need more documentation and it is not readable for a non-slang
programmer. But something like this, too:

define vinsert ()
{
   _NARGS-1; Sprintf; insert;
}

I don't think this is problem, because every programming language has its
peculiarities and you can't read it if you don't know the language.

> One way to control the stack would be to use sth similar
> to _auto_declare (or _boseos_info).
> If the compilation unit would for example declare
>    _strict_return = 1

slsh> message(_slang_version_string);
2.0.4
slsh> message(_strict_return);
_strict_return is undefined
<stdin>:2:<top-level>:Undefined Name

> then all functions that leave sth on the stack would have
> to push the result on the stack with return.

Yes. This is exactly what I am searching for.

> Such byte-compiled functions would look like this
>     A = stack_pointer
>     .... compiled body ....
>     if (stack_pointer - A != _NRESULTS) do_error(...)

This can be done with slang? Is it possible for an eos handler to get
the number of arguments of return?

> In some cases one would need to return a different number of
> values even when _strict_return = 1. This could be done by
> setting _NRESULTS inside the function:
>
> define foo()
> {
>     _NRESULTS = 2;
>     push("abcde");
>     ....
>     return 5;

Why not use return("abcde", 5)?

Bye, Jörg.
-- 
Professor: "Gott", unverständliches und mythisches Wesen, das sich einmal
  pro Woche im Kreis der Sterblichen manifestiert um Weisheit auf Folien
  unter das Volk zu bringen.		(Dschungelbuch 11, FSU Jena)