Return (errors, multi-items, etc.)
Marc W. Mengel
mmengel at cuuxb.ATT.COM
Sat Aug 12 04:04:18 AEST 1989
Several folks have posted discussions of how we ought
to extend C to do things like
{a,b,c} = f(x,y);
or
if( error( y = f(x) ) ) { ... }
There is a very simple pardigm you can use in C for these
sorts of things. Simply using
int
MapxyToabc( x, y, a, b, c )
int x,y,*a,*b,*c;
{
*a=x+y;
*b=x-y;
...
return 1;
}
Then you can have multiple return values via multiple
pointer to result arguments, and a true/false or
0..n error code result that you can use in guarded
statements like
if( f(x,y,&a,&b,&c) ) {...}
In short, why extend the language? We can already
do these things, without changing the language.
Is
{a,b,c} = f(x,y);
really that much prettier than
f(x,y, &a,&b,&c);
???
--
Marc Mengel mmengel at cuuxb.att.com
attmail!mmengel
...!{lll-crg|att}!cuuxb!mmengel
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