Re: What about code blocks (not Forth blocks)?

From	Gerry Jackson <gerry@jackson9000.fsnet.co.uk>
Newsgroups	comp.lang.forth
Subject	Re: What about code blocks (not Forth blocks)?
Date	2013-12-29 20:45 +0000
Organization	A noiseless patient Spider
Message-ID	<l9q1l2$ff6$1@dont-email.me> (permalink)
References	(9 earlier) <2013Dec27.165339@mips.complang.tuwien.ac.at> <l9n1j5$h15$1@dont-email.me> <2013Dec28.185308@mips.complang.tuwien.ac.at> <l9n4qj$4jb$1@dont-email.me> <2013Dec29.154905@mips.complang.tuwien.ac.at>

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On 29/12/2013 14:49, Anton Ertl wrote:
> Gerry Jackson <gerry@jackson9000.fsnet.co.uk> writes:
>> On 28/12/2013 17:53, Anton Ertl wrote:
>>> Gerry Jackson <gerry@jackson9000.fsnet.co.uk> writes:
>>>> Why do you say SAVE-INPUT and RESTORE-INPUT are a failure?
>>>
>>> They do not provide any guaranteed functionality, and it's unclear
>>> what functionality they should guarantee.  E.g., the following is
>>> arguably a compliant, but useless implementation:
>>>
>>> : save-input 0 ;
>>> : restore-input drop true ;
>>>
>>> So I have been quite reluctant to use it.
>>>
>>> Also, the specification of RESTORE-INPUT with both a flag and an
>>> ambiguous condition points to the technical deficits of this kind of
>>> interface.
>>>
>>> - anton
>>>
>>
>> So why don't we attempt to correct these deficiencies. In practice they
>> have worked on most Forths I have tried, the only exception being Win32
>> Forth where it didn't always work and possibly still doesn't.
>>
>> Why not e.g.
>> - forbid the useless implementation
>> - SAVE-INPUT returns n=0 (or negative) if the input is non-restorable
>> - remove the ambiguous condition from RESTORE-INPUT and replace it with
>> a value for the returned flag e.g.
>>       -1 for non-restorable
>>       +1 for current input source incorrect
>>
>> If a system can't do these things it shouldn't provide SAVE-INPUT and
>> RESTORE-INPUT.
>>
>> I suppose that would require an RfD, is it worth it?
>
> Yes, you could write an RfD to tighten the specification of SAVE-INPUT
> and RESTORE-INPUT, and this may be the best way to go forward from
> where we are, if you want a standardized useful SAVE-INPUT
> RESTORE-INPUT.  Is it worth it?  I don't know, but if you find your
> uses of SAVE-INPUT RESTORE-INPUT useful, it would be nice if we had a
> standard that actually specifies what you find useful.
>
> As for removing the ambiguous condition, I am not sure if that is
> feasible.  I think this also covers the case where the data on the
> stack does not come from SAVE-INPUT or where the data coming from
> SAVE-INPUT was changed in some way.

Yes, good point

>
> But let's step one step back.  If we did not already have SAVE-INPUT
> RESTORE-INPUT in the standard, how would we best specify a word or
> words that provide the functionality that you use SAVE-INPUT
> RESTORE-INPUT for?  Would a wrapper word (i.e., a word takes the stuff
> you write between SAVE-INPUT and RESTORE-INPUT as xt) be useful for
> you?

I think you're assuming that SAVE-INPUT and RESTORE-INPUT occur in the 
same colon definition. That's not necessarily the case e.g. I've used 
them for two different purposes, both of which involve potentially 
multiple passes over bits of Forth source code while interpreting or 
compiling. In both cases SAVE-INPUT and RESTORE-INPUT are called in 
different colon definitions and an arbitrary amount of source code can 
occur between them. This code cannot be represented by an xt, so the 
answer is no, a wrapper approach would not be useful.

It would be nice to think that FILE-POSITION and REPOSITION-FILE could 
be used instead but when I caused a question to be raised (by Leon 
Wagner) at a Forth 200X meeting in 2011 I received a reply that there 
was no entitlement to use them on a file that was being 
interpreted/compiled. That's another area that needs clarifying IMHO.

>
> If so, I think it would be much easier to specify than an
> appropriately tightended SAVE-INPUT RESTORE-INPUT.  And that's one
> reason why we are seeing more words with wrapper-style interfaces
> (another reason is exceptions).
>

I'll think about raising an RfD to tighten the specification of the two 
words.

-- 
Gerry

Thread

What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-17 23:56 -0800
  Re: What about code blocks (not Forth blocks)? mhx@iae.nl - 2013-12-18 01:14 -0800
    Re: What about code blocks (not Forth blocks)? Mark Wills <markrobertwills@yahoo.co.uk> - 2013-12-18 01:34 -0800
    Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 02:33 -0800
      Re: What about code blocks (not Forth blocks)? Coos Haak <chforth@hccnet.nl> - 2013-12-18 14:36 +0100
        Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 06:24 -0800
          Re: What about code blocks (not Forth blocks)? Coos Haak <chforth@hccnet.nl> - 2013-12-19 02:54 +0100
            Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 22:12 -0800
      Re: What about code blocks (not Forth blocks)? mhx@iae.nl - 2013-12-18 05:43 -0800
  Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-12-18 11:21 +0000
    Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 04:31 -0800
      Re: What about code blocks (not Forth blocks)? Ilya Tarasov <ilya74.tarasov@gmail.com> - 2013-12-18 04:49 -0800
        Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 05:12 -0800
  Re: What about code blocks (not Forth blocks)? "Elizabeth D. Rather" <erather@forth.com> - 2013-12-18 08:26 -1000
    Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-18 11:03 -0800
      Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 11:21 -0800
    Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 11:19 -0800
      Re: What about code blocks (not Forth blocks)? "Elizabeth D. Rather" <erather@forth.com> - 2013-12-18 10:08 -1000
        Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2013-12-18 21:58 +0100
          Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-19 14:15 +1100
            Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-19 13:32 +0000
              Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-20 21:07 +1100
                Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-20 12:35 +0000
                Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-20 13:02 +0000
                Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-22 14:19 +1100
                Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-22 10:15 +0000
                Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-24 12:30 +1100
                Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-12-24 16:48 +0000
                Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-28 11:08 +1100
                Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-12-28 11:40 +0000
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-26 18:03 +0000
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-26 10:34 -0800
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-27 15:53 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-28 17:26 +0000
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-28 17:53 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-28 18:21 +0000
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-29 14:49 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-29 20:45 +0000
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-30 17:08 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-30 20:00 +0000
                Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-12-28 18:04 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-28 18:47 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-28 19:12 +0000
                Re: What about code blocks (not Forth blocks)? "Ed" <invalid@invalid.com> - 2013-12-28 11:09 +1100
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-28 13:45 +0000
          Re: What about code blocks (not Forth blocks)? Elizabeth D Rather <erather@forth.com> - 2013-12-18 19:04 -1000
            Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-19 09:25 +0000
            Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-19 05:00 -0800
        Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-18 23:41 -0800
        Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-19 01:00 -0800
        Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-19 02:47 -0800
          Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-19 11:23 +0000
            Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-19 03:52 -0800
  Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-19 15:58 +0000
    Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-19 10:05 -0800
      Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-19 20:07 +0000
        Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-19 12:33 -0800
          Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-19 20:33 +0000
            Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-12-19 20:52 +0000
            Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-19 18:52 -0800
          Re: What about code blocks (not Forth blocks)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-12-28 12:52 -0600
            Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-28 11:47 -0800
              Re: What about code blocks (not Forth blocks)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-12-29 07:39 -0600
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-29 08:11 -0800
            Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-29 15:25 +0000
              Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-29 08:15 -0800
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-29 16:03 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-29 20:54 +0000
                Re: What about code blocks (not Forth blocks)? mhx@iae.nl - 2013-12-29 13:38 -0800
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-30 17:04 +0000
                Re: What about code blocks (not Forth blocks)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-12-30 20:05 +0000
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2013-12-30 16:49 -0800
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-01-02 17:27 +0000
              Re: What about code blocks (not Forth blocks)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-12-29 16:40 -0600
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-30 16:51 +0000
                Re: What about code blocks (not Forth blocks)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-12-30 11:15 -0600
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-30 17:37 +0000
                Re: What about code blocks (not Forth blocks)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-12-30 12:07 -0600
        Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-20 13:50 +0000
      Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2013-12-19 21:49 -0800
        Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2013-12-20 08:56 +0000
          Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-04-03 19:13 -0700
        Re: What about code blocks (not Forth blocks)? "WJ" <w_a_x_man@yahoo.com> - 2014-03-11 05:35 +0000
          Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2014-03-11 12:59 +0100
            Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-11 23:44 -0700
              Re: What about code blocks (not Forth blocks)? Julian Fondren <ayrnieu@gmail.com> - 2014-03-12 11:48 -0700
                Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2014-03-12 20:21 +0100
                Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-12 23:35 -0700
                Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2014-03-14 14:25 +0000
                Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2014-03-14 16:36 +0100
                Re: What about code blocks (not Forth blocks)? mhx@iae.nl - 2014-03-14 11:27 -0700
                Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-16 17:38 -0700
                Re: What about code blocks (not Forth blocks)? "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-03-17 03:35 -0400
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2014-03-17 20:36 -0700
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-18 13:13 +0000
                Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-03-18 14:28 +0000
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2014-03-18 10:10 -0700
                Re: What about code blocks (not Forth blocks)? Paul Rubin <no.email@nospam.invalid> - 2014-03-25 12:54 -0700
                Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-25 23:09 -0700
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-26 13:49 +0000
                Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2014-03-26 22:07 +0100
                Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-20 22:11 -0700
                Re: What about code blocks (not Forth blocks)? hughaguilar96@yahoo.com - 2014-03-28 22:18 -0700
                Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2014-03-29 10:57 +0000
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-13 16:42 +0000
          Re: What about code blocks (not Forth blocks)? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-03-11 12:51 +0000
            Re: What about code blocks (not Forth blocks)? "Alex McDonald" <blog@rivadpm.com> - 2014-03-11 14:54 +0000
    Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-19 21:36 -0800
      Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-20 16:56 +0000
    Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-19 23:24 -0800
      Re: What about code blocks (not Forth blocks)? mhx@iae.nl - 2013-12-20 02:05 -0800
      Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-20 12:41 +0000
        Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-20 17:46 +0000
          Re: What about code blocks (not Forth blocks)? Alexander Skobelev <al.skobelev@gmail.com> - 2013-12-21 08:11 -0800
            Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-23 10:07 +0000
              Re: What about code blocks (not Forth blocks)? Bernd Paysan <bernd.paysan@gmx.de> - 2013-12-23 19:31 +0100
                Re: What about code blocks (not Forth blocks)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-12-26 17:45 +0000

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