Re: "Back & Forth" - Local variables

On 08-01-2025 17:27, albert@spenarnc.xs4all.nl wrote:

I was impressed with the Behringer solution.
(I didn't care about the politically correct solution.)
 ====================================
: local{ R> SWAP DUP >R @ >R >R ;
: }global R> R> R> ! >R ;
=================
 But I can do you one better.
Remember the word ;: from colorforth. That is actually a coroutine call.
I call it CO. (Present in ciforth since the year 00)

<snipped>

 With CO the example become
---------------------------------------
: LOCAL   R> SWAP DUP >R @ >R >R   CO   R> R> ! ;
 VARIABLE A
VARIABLE B
 : divide
    A LOCAL
    B LOCAL
    B ! A !  A @ B @ /
    . CR
;
 15 3 divide
---------------------------------------
 This saves a definition and a word-of-code, and a line for every
LOCAL used. Now that is closer to what Chuck Moore would have used.
Remember for Moore CO aka ;: is a standard word.
 CO is not standard but it should be, and it is elementary as hell.

Couldn't find the source for either CO or ;: but I got some primitive, high level form of co-routine in 4tH:
====================================
: yield r> r> swap >r >r ;             \ remember that ; compiles EXIT!
aka rdrop grab                         \ so add a [FORCE] when needed.
====================================
Can't say how they measure up. But I guess co-routines is something Chuck would like - since it's something you can implement quite easily. So yes, I agree Chuck wouldn't waste that line ;-)
Hans Bezemer