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Groups > comp.lang.forth > #59436
| From | anton@mips.complang.tuwien.ac.at (Anton Ertl) |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: Would ?EXIT work in all ANS-Forth systems? |
| Date | 2017-05-17 16:14 +0000 |
| Organization | Institut fuer Computersprachen, Technische Universitaet Wien |
| Message-ID | <2017May17.181425@mips.complang.tuwien.ac.at> (permalink) |
| References | (6 earlier) <d5GdnW8mjMeYUYfEnZ2dnUU7-c3NnZ2d@supernews.com> <2017May16.122829@mips.complang.tuwien.ac.at> <W6mdnQe9aam6g4bEnZ2dnUU7-UnNnZ2d@supernews.com> <2017May16.183409@mips.complang.tuwien.ac.at> <V_SdnQBzw5l8pIbEnZ2dnUU7-dvNnZ2d@supernews.com> |
Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>I don't think that there's anything Java-specific (or in any way
>language-specific) about the idea that exceptions should be
>exceptional.
Sure, but does that mean that CATCH and THROW should be exceptional?
Why? Just because they were originally intended for exceptions? Not
a sufficient reason.
> It may well be that there is something special about
>Forth (and there are many special things!) which means that CATCH and
>THROW should be used for more for things than other languages do, but
>right now I can't think of any reason why there might be.
Maybe you did not get <2017Feb13.175259@mips.complang.tuwien.ac.at>
after all.
The reason is that, in Forth, you frequently have to do some sequence
of 2DROP DROP FDROP 2r> 2DROP or somesuch in order to clean up
no-longer needed arguments on the stacks. That's especially annoying
if you have to deal with a bunch of dependent conditions that you have
to check with ifs. You get code like:
: foo
2dup check-something if
dup >r check-something-else if
2dup fdup check-yet-another-thing if
do the thing that depends on these conditions
clean up the stacks exit then
clean up the stacks for this branch exit then
clean up the stacks for this branch exit then
clean up the stacks for this branch ;
Or you can organize this with ELSEs; or with each IF in a separate
word, with local cleanups, but possibly long stack effects. Or you
put the data in variables so that you don't have to worry about their
presence on the stacks; but wait, we are now in a multi-core world, so
we have to put it in user variables, and this local data will cost
space in every task.
Or, alternatively, you use THROW's ability to clean up all the stacks:
[: 2dup check-something ?lthrow
dup >r check-something-else ?lthrow
2dup fdup check-yet-another-thing ?throw
do the thing that depends on these conditions
clean up the stacks
;] lexec
If the "do the thing" part leaves nothing on the stack, its cleanup
can be done by an LTHROW, too.
This style allows us to think about this code linearly instead of as a
complex IF cascade, and it frees us from having to adjust one or more
else branches whenever we change something in the checks.
- anton
--
M. Anton Ertl http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
New standard: http://www.forth200x.org/forth200x.html
EuroForth 2017: http://www.euroforth.org/ef17/
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Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-10 08:21 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-10 16:39 +0100
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-10 08:46 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-10 16:04 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-11 04:22 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-11 10:35 +0100
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-11 05:08 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Julian Fondren <julian.fondren@gmail.com> - 2017-05-11 03:51 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-11 07:02 -0500
Re: Would ?EXIT work in all ANS-Forth systems? rickman <gnuarm@gmail.com> - 2017-05-13 11:55 -0400
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 09:32 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Cecil Bayona <cbayona@cbayona.com> - 2017-05-15 11:56 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 12:20 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Cecil Bayona <cbayona@cbayona.com> - 2017-05-15 12:31 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 15:50 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-10 16:49 +0000
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-10 12:04 -0700
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-11 01:08 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-11 09:13 +0100
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-11 01:48 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-11 09:59 +0100
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-12 14:20 +0000
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-12 17:01 -0700
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-12 22:18 -0700
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-13 03:09 -0700
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-13 21:07 +1000
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-13 14:20 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-14 11:59 +1000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-14 09:21 -0500
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-14 10:43 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-14 18:35 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Lars Brinkhoff <lars.spam@nocrew.org> - 2017-05-15 07:11 +0200
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 04:35 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Julian Fondren <julian.fondren@gmail.com> - 2017-05-15 03:54 -0700
Re: Would ?EXIT work in all ANS-Forth systems? mhx@iae.nl - 2017-05-15 04:07 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 06:23 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Julian Fondren <julian.fondren@gmail.com> - 2017-05-15 06:53 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 09:18 -0500
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-14 22:44 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 04:16 -0500
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-16 02:00 -0700
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-16 02:43 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-16 05:08 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-16 12:11 +0000
Re: Would ?EXIT work in all ANS-Forth systems? NN <november.nihal@gmail.com> - 2017-05-17 05:24 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-17 07:35 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-17 14:59 +0100
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-17 13:30 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-15 11:09 +1000
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-14 21:17 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Lars Brinkhoff <lars.spam@nocrew.org> - 2017-05-15 07:13 +0200
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-16 10:24 +1000
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-16 01:13 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-16 12:26 +0000
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-17 01:58 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-17 16:45 +0000
Re: Would ?EXIT work in all ANS-Forth systems? obi65537@gmail.com - 2017-05-25 12:04 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-26 10:02 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-26 07:46 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-26 13:53 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-26 10:14 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Cecil Bayona <cbayona@cbayona.com> - 2017-05-26 10:16 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-26 08:59 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Cecil Bayona <cbayona@cbayona.com> - 2017-05-26 11:27 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-26 10:19 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Lars Brinkhoff <lars.spam@nocrew.org> - 2017-05-26 20:20 +0200
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-26 21:38 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Cecil Bayona <cbayona@cbayona.com> - 2017-05-26 14:06 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-26 22:00 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-26 17:06 +0000
Re: Would ?EXIT work in all ANS-Forth systems? hum9 <obi65537@gmail.com> - 2017-05-27 01:15 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-28 14:17 +0000
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-27 17:40 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-24 15:46 +1000
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <obi65537@gmail.com> - 2017-05-25 11:51 -0700
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <obi65537@gmail.com> - 2017-05-25 20:38 -0700
Re: Would ?EXIT work in all ANS-Forth systems? obi65537@gmail.com - 2017-05-25 22:03 -0700
Re: Would ?EXIT work in all ANS-Forth systems? obi65537@gmail.com - 2017-05-25 22:09 -0700
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-26 21:56 +1000
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-26 13:30 +0100
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-27 15:04 +1000
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-27 17:33 +0100
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-29 12:17 +1000
Re: Would ?EXIT work in all ANS-Forth systems? hum9 <obi65537@gmail.com> - 2017-05-27 00:33 -0700
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-27 14:53 +1000
READ-FILE over-specified? "HAA" <someone@microsoft.com> - 2017-05-27 21:28 +1000
Re: READ-FILE over-specified? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-27 13:11 +0000
Re: READ-FILE over-specified? "HAA" <someone@microsoft.com> - 2017-05-29 13:47 +1000
Re: READ-FILE over-specified? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-05-28 09:44 +0200
Re: READ-FILE over-specified? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-28 13:41 +0000
Re: READ-FILE over-specified? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-05-28 19:59 +0200
Re: Would ?EXIT work in all ANS-Forth systems? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2017-05-16 09:42 +0100
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-16 09:53 +0100
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-16 04:53 -0500
Re: Would ?EXIT work in all ANS-Forth systems? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-05-16 12:32 +0200
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-16 12:35 +0100
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-16 10:48 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-16 18:23 +0100
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-17 04:33 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-17 12:29 +0100
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-16 10:28 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-16 10:43 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-16 16:34 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-16 12:41 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-17 16:14 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-18 03:05 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-18 16:33 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-18 12:43 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-18 04:01 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-18 15:41 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-18 11:58 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-18 22:57 +0100
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-17 00:32 +1000
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-16 15:53 +0100
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-15 05:29 +0000
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-14 23:00 -0700
Re: Would ?EXIT work in all ANS-Forth systems? rickman <gnuarm@gmail.com> - 2017-05-17 12:27 -0400
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-15 09:16 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-15 09:55 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-13 14:25 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Julian Fondren <julian.fondren@gmail.com> - 2017-05-13 07:49 -0700
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-15 09:59 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-15 12:22 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-13 14:19 +0000
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-14 23:23 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-15 00:10 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-15 09:35 +0000
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-15 00:54 -0700
Return-address manipulation (was: Would ?EXIT ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-15 08:47 +0000
Re: Return-address manipulation (was: Would ?EXIT ...) stephen@mpeforth.com (Stephen Pelc) - 2017-05-15 11:53 +0000
Re: Return-address manipulation (was: Would ?EXIT ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-16 13:03 +0000
Re: Return-address manipulation (was: Would ?EXIT ...) Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-16 07:06 -0700
Re: Return-address manipulation (was: Would ?EXIT ...) Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-16 07:14 -0700
Re: Would ?EXIT work in all ANS-Forth systems? "Elizabeth D. Rather" <erather@forth.com> - 2017-05-14 21:58 -1000
Re: Would ?EXIT work in all ANS-Forth systems? stephen@mpeforth.com (Stephen Pelc) - 2017-05-15 11:23 +0000
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