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Groups > comp.lang.forth > #36429

Re: Static Single Assignment form to Stack allocation

From "Alex McDonald" <blog@rivadpm.com>
Newsgroups comp.lang.forth
Subject Re: Static Single Assignment form to Stack allocation
Date 2015-02-10 14:33 +0000
Organization A noiseless patient Spider
Message-ID <mbd4qk$q04$1@dont-email.me> (permalink)
References <82c4c3dc-7692-4d03-a447-9bdd54ff9387@googlegroups.com> <mb8gem$ev7$1@dont-email.me> <5bbc76d4-6847-4e8d-8e55-68a4d5ffa118@googlegroups.com> <mbcshk$nri$1@dont-email.me> <54d9ff6a$0$3895$e4fe514c@dreader34.news.xs4all.nl>

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on 10/02/2015 12:54:00,  wrote:
> In article <mbcshk$nri$1@dont-email.me>,
> Alex McDonald <blog@rivadpm.com> wrote:
>>on 10/02/2015 06:49:14,  wrote:
>>> On Sunday, February 8, 2015 at 1:21:15 PM UTC-7, Alex McDonald wrote:
>>>> on 08/02/2015 18:13:40,  wrote:
>>>> > On Saturday, February 7, 2015 at 6:35:37 PM UTC-7, Elizabeth D. Rather
>>>> > wrot e:
>>>> >> The term "control flow stack" was coined in Forth94 to allow it to
>>>> >> describe the functions of these control structure words without
>>>> >> *mandating* an implementation using the data stack, although that is the
>>>> >> most common strategy.
>>>> >
>>>> > By allowing the data-stack to be used as the control-flow stack,
>>>> > ANS-Forth requires programmers to assume that the data-stack is the
>>>> > control-flow stack in order for their programs to work on all
>>>> > ANS-Forth systems --- this is effectively the same as mandating that
>>>> > the data-stack be used as the control-flow stack.
>>>>
>>>> It isn't.
>>>>
>>>> >
>>>> > The standard needs to require that the control-flow stack behave as a
>>>> > distinct stack (not to have its data intermingled with the user's
>>>> > data on the data-stack) --- this is necessary for anybody to write a
>>>> > standard program tha t assumes that the control-flow stack is
>>>> > distinct.
>>>>
>>>> Only when compiling. Is there a consistently used metaphor in Forth that
>>>> requires user data on the stack while compiling? Can you provide one?
>>>
>>> LITERAL
>>>
>>
>>(I meant idiomatic, not metaphorical, but you got what I meant.)
>>
>>The commonest idiom I've seen for LITERAL is
>>
>>: foo ... [ buf-size maxbuffer - ] literal ... ;
>>
>>The compile is suspended so we can optimise away sets of constants to a
>>single constant that we then compile with LITERAL. It doesn't matter
>>what's on the data stack at this point, whether it be control flow values
>>or not.
>>
>>Where this wouldn't work is
>>
>>: foo ... [ buf-size maxbuffer - dup 1+ ] if literal else literal then
>>.. ;
>>
>>Here the control flow, if on the data stack, has pushed down the literals
>>and we can't get at them. Are you claiming this is idiomatic, with use of
>>LITERAL inside a control flow where the literal value is put on the stack
>>before it?
>>
> 
> If Hugh isn't, I am. And it is a pitfall because one needs to read the
> standard very carefully to realize that : might leave something on the
> control stack.
> 
> Groetjes Albert

There isn't any extant code that makes use of data on the stack at
compile time the way I suggested, and for the following fairly obvious
reason. The standard makes it clear that there are certain features of
compile time where the data stack may be used as a control flow stack. So
there is no code that can take advantage of control flow stack not being
data stack, since most popular ANS Forth compilers use the data stack for
control flow, and no-one normally writes code that won't run.

What Hugh and you need to do is demonstrate that there's a requirement or
use case, or some cool idiom that we're all missing out on, due to this
feature of the language. It applies only to LITERAL and COMPILE, (and
possibly EXECUTE), since there's not a lot else you can do with a value
on the stack at compile time; it's either a number or it's an XT. 

Standards get modified & developed over time by demonstrating a need for
change. Not by claiming pitfalls because you didn't read the doc. It
clearly marks control stack use as C: in stack diagrams.

6.1.0450 : “colon” CORE ( C: “<spaces>name” -- colon-sys )

I read the standard pretty regularly. I don't always get it right or
understand it correctly, but I don't then claim that the standard is
stupid or negligent or some homosexual conspiracy because it wasn't
written how I wanted it to read.

Frankly, I can't see the use case that would give us significant
advantages if the current restriction were changed.

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Thread

Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-05 20:01 -0800
  Re: Static Single Assignment form to Stack allocation Paul Rubin <no.email@nospam.invalid> - 2015-02-05 21:00 -0800
    Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-06 02:15 -0500
      Re: Static Single Assignment form to Stack allocation Paul Rubin <no.email@nospam.invalid> - 2015-02-06 12:07 -0800
        Re: Static Single Assignment form to Stack allocation Jan Coombs <Jan-54 <jenfhaomndgfwutc@murmic.plus.com>> - 2015-02-08 22:38 +0000
          Re: Static Single Assignment form to Stack allocation Paul Rubin <no.email@nospam.invalid> - 2015-02-08 14:55 -0800
            Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-08 19:59 -0800
  Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-06 13:15 +0000
  Re: Static Single Assignment form to Stack allocation anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-06 13:22 +0000
    Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-06 11:16 -0800
      Re: Static Single Assignment form to Stack allocation Paul Rubin <no.email@nospam.invalid> - 2015-02-06 12:05 -0800
      Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-02-06 16:44 -0800
        Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-06 23:41 -0500
      Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-06 23:41 -0500
        Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-07 19:22 +0000
          Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-07 13:09 -0800
            Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-07 11:25 -1000
              Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-07 14:09 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-07 22:32 +0000
                Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-07 14:51 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-08 00:04 +0000
                Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-07 17:03 -0800
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-07 21:04 -0500
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-07 21:10 -0500
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-08 10:57 +0000
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-07 21:05 -0500
            Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-07 22:24 +0000
          Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-07 11:21 -1000
          Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-07 20:11 -0500
            Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-07 15:35 -1000
              Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-07 16:52 -1000
                Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-02-08 10:21 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-08 20:09 +0000
                Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-08 17:15 -1000
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-09 12:00 +0000
                Re: Static Single Assignment form to Stack allocation albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-09 13:05 +0000
                Re: Static Single Assignment form to Stack allocation "HAA" <someone@microsoft.com> - 2015-02-10 16:01 +1100
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-09 02:35 -0500
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-09 12:03 +0000
              Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-02-08 10:13 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-08 20:21 +0000
                Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-02-09 22:49 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-10 12:12 +0000
                Re: Static Single Assignment form to Stack allocation albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-10 12:54 +0000
                Re: Static Single Assignment form to Stack allocation Mark Wills <markwills1970@gmail.com> - 2015-02-10 06:30 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-10 14:53 +0000
                Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-10 08:20 -1000
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-10 14:33 +0000
                Re: Static Single Assignment form to Stack allocation albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-10 19:09 +0000
                Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-10 14:29 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) "Alex McDonald" <blog@rivadpm.com> - 2015-02-10 15:49 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-10 17:56 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) "Alex McDonald" <blog@rivadpm.com> - 2015-02-10 20:53 +0000
                Re: Control-flow stack "Elizabeth D. Rather" <erather@forth.com> - 2015-02-10 13:08 -1000
                Re: Control-flow stack awegel@arcor.de (Alexander Wegel) - 2015-02-11 03:15 +0100
                Re: Control-flow stack hughaguilar96@gmail.com - 2015-02-10 18:47 -0800
                Re: Control-flow stack Unknown <dog@gmail.com> - 2015-02-17 07:13 +0000
                Re: Control-flow stack anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-11 17:59 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-02-11 01:30 -0800
                Re: Control-flow stack (was: Static Single Assignment ...) "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-10 18:43 -0500
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-11 17:46 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) "Alex McDonald" <blog@rivadpm.com> - 2015-02-11 22:39 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) "Alex McDonald" <blog@rivadpm.com> - 2015-02-11 22:42 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-12 09:52 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) "Alex McDonald" <blog@rivadpm.com> - 2015-02-12 10:28 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-11 20:23 -0800
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-12 07:21 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-12 18:33 -0800
                Re: Control-flow stack awegel@arcor.de (Alexander Wegel) - 2015-02-13 04:46 +0100
                Re: Control-flow stack "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-13 06:48 -0500
                Re: Control-flow stack awegel@arcor.de (Alexander Wegel) - 2015-02-13 13:40 +0100
                Re: Control-flow stack albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-13 15:49 +0000
                Re: Control-flow stack awegel@arcor.de (Alexander Wegel) - 2015-02-14 03:47 +0100
                Re: Control-flow stack anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-13 16:09 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-13 15:20 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-13 21:31 -0800
                Re: Control-flow stack awegel@arcor.de (Alexander Wegel) - 2015-02-14 03:47 +0100
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-14 19:22 -0800
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-15 11:09 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-15 16:57 -0800
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-16 14:41 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-16 18:43 -0800
                Re: Control-flow stack Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-02-10 22:04 +0000
                Re: Control-flow stack Harold <hzrabbie@gmail.com> - 2015-02-10 16:58 -0800
                Re: Control-flow stack Bernd Paysan <bernd.paysan@gmx.de> - 2015-02-11 02:51 +0100
                Re: Control-flow stack albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-11 11:34 +0000
                Re: Control-flow stack Harold <hzrabbie@gmail.com> - 2015-02-11 08:17 -0800
                Re: Control-flow stack "Elizabeth D. Rather" <erather@forth.com> - 2015-02-10 16:37 -1000
                Re: Control-flow stack hughaguilar96@gmail.com - 2015-02-10 18:57 -0800
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-10 18:44 -0500
                Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-10 14:49 -1000
                Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-02-10 18:16 -0800
                Re: Static Single Assignment form to Stack allocation Mark Wills <markwills1970@gmail.com> - 2015-02-11 00:35 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-11 09:35 +0000
                Re: Static Single Assignment form to Stack allocation Mark Wills <markwills1970@gmail.com> - 2015-02-11 03:06 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-11 14:27 +0000
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-11 14:40 +0000
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-12 20:02 -0500
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-13 11:42 +0000
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-13 07:44 -0500
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-13 14:20 +0000
                Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-13 10:32 -1000
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <bork@lllljunkqwer.cpm> - 2015-03-29 16:27 -0400
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-03-29 22:46 +0100
                Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-03-29 15:24 -1000
                Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-03-30 04:44 -0700
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-03-30 15:33 +0100
                Re: Static Single Assignment form to Stack allocation anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-11 18:03 +0000
                Re: Static Single Assignment form to Stack allocation Bernd Paysan <bernd.paysan@gmx.de> - 2015-02-12 00:16 +0100
                Re: Static Single Assignment form to Stack allocation anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-12 07:08 +0000
            Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-08 10:51 +0000

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