Re: Back & Forth - Co-routines

On 2025-01-31 11:33, dxf wrote:

 Not sure if previously mentioned but here's another version of LOCAL
 : ;:  >r ;
 : LOCAL ( x adr -- )
   r> -rot dup @ over 2>r ! ;: 2r> ! ;
 variable A  variable B  8 a !  7 b !
 : divide ( a b -- )  b local  a local
   a @  b @  /  . cr  ;
 15 3 divide  a ? b ?
 

This approach does not work well with catch/throw. Because `throw` must restore the values of all "local" variables that are used in the definitions whose execution is being terminated. And this is difficult to implement.
See also 13.3.3.1, item c,
<https://forth-standard.org/standard/locals#subsubsection.13.3.3.1>
| ABORT shall release all local storage resources,
| and CATCH / THROW (if implemented) shall release
| such resources for all definitions whose execution
| is being terminated.
--
Ruvim