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Groups > comp.lang.forth > #44563
| From | "HAA" <someone@microsoft.com> |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: BEGIN WHILE UNTIL THEN |
| Date | 2016-01-05 12:17 +1100 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <n6f5f5$usl$1@gioia.aioe.org> (permalink) |
| References | <08c4616c-21ad-4bdf-9fe4-a9e5ee2e5dad@googlegroups.com> <n6f2bj$qgs$1@gioia.aioe.org> <70db56dd-4768-4b8d-b94d-fb3200806866@googlegroups.com> |
Julian Fondren wrote:
> On Monday, January 4, 2016 at 6:24:21 PM UTC-6, HAA wrote:
> > Julian Fondren wrote:
> > > Hello clf,
> > >
> > > The following code is from SwoopPortable.f
> > > ...
> > > Can someone rewrite this with normal control-flow?
> >
> > By 'normal' you mean pre Forth-94? You don't say why you need such a
> > thing. It matters because the result will likely be longer less efficient code.
>
> By normal I mean, not requiring me to drop the pretense of
> structured programming, not requiring me to interpret these
> words as just performing conditional and unconditional GOTOs.
It's all GOTOs 'under the hood' :)
>
> Personally, the benefits to this kind of programming aren't
> worth it. It's too hard to understand. It abuses the *names*
> of words. THEN isn't THEN, really; it's just "resolve last
> forward branch". I'd rather just have numbers in my code, like
> I think one of Rick Hohensee's Forths:
>
> : stars ( n -- )
> dup 0>= ?->(0) ." I don't how to display negative stars" abort
> (0) dup 0= ?->(1) 1- ." *" ->(0)
> (1) drop ;
>
> (n) is a branch target.
> ->(n) branches to it.
> ?->(n) conditionally branches to it.
>
> Ugly? At least it does what it says, and no different.
>
> Anyway, the SwoopPortable.f version breaks under ciforth.
> ciforth's THEN complains at compile-time about control flow
> balance, and if that error is neutralized, it just miscompiles
> the definition and fails at runtime.
It's trivial for implementers to make WHILE Forth-94 compatible
even they choose not to use it.
> (I'm aware that there are *many* other ways in which ciforth
> can't handle SwoopPortable.f. I bridged many of those gaps to
> come to this point.)
Try this (untested)
: UPDATE-LINKS ( super link -- )
>R BEGIN
DUP @ DUP
WHILE \ prev cur
R@ BEGIN \ prev cur sup
@ DUP
WHILE \ prev cur sup'
2DUP = IF 2DROP R> @ SWAP ! EXIT THEN
REPEAT DROP NIP
REPEAT R> DROP 2DROP ;
VFX reports 96 bytes, 37 instructions compared with 90 bytes, 36 instructions
for the original. So not much difference in this case (one extra jump).
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BEGIN WHILE UNTIL THEN Julian Fondren <julian.fondren@gmail.com> - 2016-01-04 14:50 -0800
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-05 11:24 +1100
Re: BEGIN WHILE UNTIL THEN Julian Fondren <julian.fondren@gmail.com> - 2016-01-04 16:47 -0800
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-05 12:17 +1100
Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-05 10:51 +0000
Re: BEGIN WHILE UNTIL THEN stephen@mpeforth.com (Stephen Pelc) - 2016-01-05 15:06 +0000
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-04 17:25 -0800
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-05 13:06 +1100
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-04 21:42 -0800
Re: BEGIN WHILE UNTIL THEN rickman <gnuarm@gmail.com> - 2016-01-05 01:48 -0500
Re: BEGIN WHILE UNTIL THEN Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-01-05 11:15 +0000
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-06 14:35 +1100
Re: BEGIN WHILE UNTIL THEN Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-01-05 02:04 +0000
Re: BEGIN WHILE UNTIL THEN Julian Fondren <julian.fondren@gmail.com> - 2016-01-04 18:37 -0800
Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-04 19:17 -0800
Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-05 11:10 +0000
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-06 15:02 +1100
Re: BEGIN WHILE UNTIL THEN november.nihal@gmail.com - 2016-01-05 08:03 -0800
Re: BEGIN WHILE UNTIL THEN november.nihal@gmail.com - 2016-01-05 08:07 -0800
Re: BEGIN WHILE UNTIL THEN november.nihal@gmail.com - 2016-01-05 08:18 -0800
Re: BEGIN WHILE UNTIL THEN november.nihal@gmail.com - 2016-01-05 08:21 -0800
Re: BEGIN WHILE UNTIL THEN Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-01-07 05:13 -0500
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-08 12:36 +1100
Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-08 10:32 +0000
Re: BEGIN WHILE UNTIL THEN Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-01-08 02:55 -0800
Re: BEGIN WHILE UNTIL THEN Coos Haak <chforth@hccnet.nl> - 2016-01-08 13:57 +0100
Re: BEGIN WHILE UNTIL THEN Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-01-08 06:55 -0800
Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-08 15:06 -0800
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-08 16:59 -0800
Re: BEGIN WHILE UNTIL THEN "Elizabeth D. Rather" <erather@forth.com> - 2016-01-08 16:15 -1000
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-08 22:23 -0800
Re: BEGIN WHILE UNTIL THEN "Elizabeth D. Rather" <erather@forth.com> - 2016-01-08 21:12 -1000
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-09 08:04 -0800
Re: BEGIN WHILE UNTIL THEN "Elizabeth D. Rather" <erather@forth.com> - 2016-01-09 09:16 -1000
Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-10 15:31 +0000
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-10 08:11 -0800
Re: BEGIN WHILE UNTIL THEN "Elizabeth D. Rather" <erather@forth.com> - 2016-01-10 09:42 -1000
Re: BEGIN WHILE UNTIL THEN Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-01-11 13:02 +0000
Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-13 16:20 +0000
Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-10 14:10 -0800
Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-11 18:38 -0800
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-14 08:47 +1100
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-13 17:24 -0800
Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-13 19:25 -0800
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-14 22:09 +1100
Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-14 16:21 +0000
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-16 11:34 +1100
Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-16 03:43 +0100
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-19 18:01 +1100
Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-19 23:07 +0100
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-21 14:29 +1100
Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-21 22:25 +0100
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-24 13:28 +1100
Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-25 01:31 +0100
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-25 21:45 +1100
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-25 10:24 -0800
Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-25 20:41 +0100
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-28 20:39 +1100
Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-28 16:05 +0100
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-21 20:52 -0800
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-24 13:16 +1100
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-14 08:46 -0800
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-16 11:34 +1100
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-15 20:53 -0800
Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-13 19:31 -0800
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-11 09:29 +1100
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-10 21:18 -0800
Re: BEGIN WHILE UNTIL THEN Paul Rubin <no.email@nospam.invalid> - 2016-01-10 21:29 -0800
Re: BEGIN WHILE UNTIL THEN "Elizabeth D. Rather" <erather@forth.com> - 2016-01-10 20:37 -1000
Re: BEGIN WHILE UNTIL THEN Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-01-11 09:05 +0000
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-12 12:26 +1100
Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-10 14:18 -0800
Re: BEGIN WHILE UNTIL THEN Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-01-08 23:31 -0800
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-09 08:09 -0800
Re: BEGIN WHILE UNTIL THEN Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-01-09 05:31 -0600
Re: BEGIN WHILE UNTIL THEN Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-01-09 07:52 -0600
Re: BEGIN WHILE UNTIL THEN Ron Aaron <rambamist@gmail.com> - 2016-01-09 18:22 +0200
Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-09 16:29 +0000
Re: BEGIN WHILE UNTIL THEN stephen@mpeforth.com (Stephen Pelc) - 2016-01-08 11:23 +0000
Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-10 20:17 -0800
Re: BEGIN WHILE UNTIL THEN stephen@mpeforth.com (Stephen Pelc) - 2016-01-11 11:56 +0000
Re: BEGIN WHILE UNTIL THEN Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-01-11 11:59 +0000
generalized CASE (was: BEGIN WHILE UNTIL THEN) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-11 12:30 +0000
Re: generalized CASE (was: BEGIN WHILE UNTIL THEN) hughaguilar96@gmail.com - 2016-01-11 13:52 -0800
Re: generalized CASE Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-01-11 22:00 +0000
Re: generalized CASE Coos Haak <chforth@hccnet.nl> - 2016-01-12 01:50 +0100
Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-11 14:16 -0800
Re: BEGIN WHILE UNTIL THEN Chris Curl <ccurl609@gmail.com> - 2016-01-11 16:17 -0800
Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-12 13:07 +0000
Re: BEGIN WHILE UNTIL THEN Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-01-12 20:48 +0000
Re: BEGIN WHILE UNTIL THEN hughaguilar96@gmail.com - 2016-01-12 14:16 -0800
Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-08 16:21 +0000
Re: BEGIN WHILE UNTIL THEN stephen@mpeforth.com (Stephen Pelc) - 2016-01-08 20:12 +0000
Re: BEGIN WHILE UNTIL THEN anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-01-09 18:19 +0000
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-11 09:34 +1100
Re: BEGIN WHILE UNTIL THEN Bernd Paysan <bernd.paysan@gmx.de> - 2016-01-08 21:13 +0100
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-09 23:46 +1100
Re: BEGIN WHILE UNTIL THEN Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-01-08 10:11 -0500
Re: BEGIN WHILE UNTIL THEN "HAA" <someone@microsoft.com> - 2016-01-11 08:38 +1100
Re: BEGIN WHILE UNTIL THEN november.nihal@gmail.com - 2016-01-08 03:04 -0800
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