[REBOL] Re: tailfunc
From: lmecir:mbox:vol:cz at: 21-Nov-2001 16:41
Hi Romano,
<<Romano>>
And why not an in-line function like:
compose...
do (func [] reduce [body])
<</Romano>>
Your suggestion doesn't seem to work (?) ...
<<Romano>>
I have others little questions on your code:
1) A little thing: couldn't loop start to none?
loop: none
...
either loop [
loop: 1
] [
until [
loop: none
error? set/any 'result do (func [] reduce [body])
not loop
]
loop: none
<</Romano>>
Loop surely can start with the None value. But even then for the function to
work, we have to be able to detect three different states:
1) the first one is a fresh start, signaling that the loop must be started.
2) the second one is a situation, when the loop is "running" and a recursive
call was detected. The loop must continue.
3) the third one is a situation, when the loop is "running" and a recursive
call hasn't been detected. The loop must finish.
If we want to use logic! values, we have to use two variables, e.g. like:
loop: none
...
either loop [
finish: none
] [
until [
finish: true
error? set/any 'result exec (reduce [body])
finish
]
loop: none
...
<<Romano>>
2) You leave 'result global, why?
---
Ciao
Romano
<</Romano>>
Not only 'result, I left even the 'locals word global! It is a bug, I will
repair it and include to %Highfun.r Thanks for your feedback.
Cheers
Ladislav
