Re: Back & Forth - Co-routines

On 1/02/2025 10:19 pm, Ruvim wrote:

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.
...

It is locals on the cheap.  When I've resorted to something like this it's
because I needed re-entrancy on a variable and full-blown locals weren't worth
loading.  As I never considered catch/throw until you mentioned it, presumably
it wasn't an issue in those cases.  But yes, it warrants a warning.