Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!willett!ForthNet
From: ForthNet@willett.UUCP (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: Category 10,  Topic 16
Message-ID: <178.UUL1.3#5129@willett.UUCP>
Date: 5 Jan 90 16:04:23 GMT
Organization: Latest Link in ForthNet Chain
Lines: 51

Category 10,  Topic 16
Message 83        Sun Dec 24, 1989
R.BERKEY [Robert]            at 09:06 PST


 Roedy Green writes:

 RG> 7.0610  ?DO
 RG>     You might consider changing the definition to match
 RG>     Ray Duncan's so that -LOOP works too.


I agree.

(1)   The ?DO 's that I know of all have the same definition.  It's a
fundamental definition, which, for example, appears in the 8086 REP opcode.

(2) The BASIS ?DO is easy to code in high level with the conventional ?DO :

   ... OVER MIN ?DO ...

while there is no way to implement a conventional ?DO with the BASIS ?DO .

(3) The justification given for a new ?DO is itself outside the scope of a
Standard Program:  that during development, getting the parameters backwards
leads to pushing the reset button.  I don't see this as substantive: it only
happens to me a few times a year, and many programmers have an interrupt
function that obviates the need for a reset even then.

(4) Adding the new ?DO to existing code with the conventional ?DO requires
either analysis of compatibility for all cases, or finding a new name for ?DO
.  Why find a new name and change existing code, when the new function can be
the one with a new name?

---

The BASIS ?DO is incompatible with existing ?DO 's in that THEN must be added
after LOOP :

   ?DO ... LOOP THEN

Suppose BASIS restores a conventional definition for the runtime of ?DO . 
Does this compilation change warrant a new name for ?DO ?  I'm inclined to say
no.


What are other opinions?  And name preferences or suggestions?

-----
This message came from GEnie via willett through a semi-automated program.
Report problems to: 'uunet!willett!dwp' or 'willett!dwp@gateway.sei.cmu.edu'