yield equivalent in C/JavaScript?

Robin Becker robin at jessikat.fsnet.co.uk
Sun Jun 30 22:05:37 CEST 2002


In message <20020630180139.GA38821 at hishome.net>, Oren Tirosh <oren-py-
l at hishome.net> writes

very smart! That Duff did it Fortran as I recall.

>On Sat, Jun 29, 2002 at 07:12:46PM +0100, Robin Becker wrote:
>> Is there any way to do yielding easily in C? I have a bunch of programs
>> which are normally connected together using unix pipes. I would like to
>> merge them and the problem is then how to get them to communicate nicely
>> using a single process.
>
>It's possible to implement this in C using Duff's Device:
>
>#define BEGIN_GENERATOR static int _GenState=0; \
>  switch(_GenState) { \
>    case 0:
>
>#define END_GENERATOR } \
>  _GenState = 0;
>
>#define YIELD(x) _GenState=__line__; return (x); case __line__:
>
>
>int generator(arguments) {
>
>  static int foo, bar, etc;    /* Make all variables static */
>
>  BEGIN_GENERATOR 
>  for(...) {
>      if(...) {
>        ...
>        YIELD(x)
>        ...
>      } else {
>        ...
>      }
>      ...
>      YIELD(y)
>      ...
>   }
>   END_GENERATOR
>}
>
>If you want this to be reentrant use a struct passed as an argument
>to the function instead of static variables.
>
>       Oren
>
>

-- 
Robin Becker





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