Re: 0 SET-ORDER why?

Date	2024-06-29 03:08 +1000
Subject	Re: 0 SET-ORDER why?
Newsgroups	comp.lang.forth
References	(3 earlier) <v5h5h6$2565d$1@dont-email.me> <667cda36$1@news.ausics.net> <v5m13j$3811n$1@dont-email.me> <667eaa3b@news.ausics.net> <v5mev6$3811n$3@dont-email.me>
From	dxf <dxforth@gmail.com>
Message-ID	<667eee23$1@news.ausics.net> (permalink)
Organization	Ausics - https://newsgroups.ausics.net

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On 28/06/2024 11:48 pm, Ruvim wrote:
> On 2024-06-28 16:19, dxf wrote:
>> On 28/06/2024 7:51 pm, Ruvim wrote:
>>> On 2024-06-27 07:19, dxf wrote:
>>>> On 26/06/2024 11:36 pm, Ruvim wrote:
>>>>> On 2024-06-26 12:50, dxf wrote:
>>>>>> ...
>>>>>> So after all that you don't have an explanation either?  You implemented
>>>>>> it as instructed in the event someone finds a use.
>>>>>
>>>>>
>>>>> I think, in this case it's better to specify behavior than to declare an ambiguous condition.
>>>>
>>>> No need to specify useless behaviours.
>>>
>>> Even behavior that is useless in practice should be sometimes specified to ensure *consistency* and expected effects.
>>>
>>> BTW, do you think 0 PICK and 0 ROLL are useless?
>>
>> No, because I've used them (at least in the case of PICK :)
>>
>>>> u=0 in REPRESENT wasn't specified as
>>>> the TC couldn't imagine a use for it.
>>>
>>> <https://forth-standard.org/standard/float/REPRESENT>
>>>
>>> Of course, it's specified. It's specified for any u, including 0.
>>> For example:
>>>    "The character string shall consist of the u most significant digits"
>>>
>>> If u is zero, the string must consist of zero digits.
>>
>> Spec says:
>>
>>     "u most significant digits of the significand"
>>
>> Do you have a definition for '0 most significant digits of the significand' ?
>> I don't.  Nor did ANS provide one.
> 
> It's seems obvious to me: 0 digits means the empty string.

REPRESENT does two things:
- Round the number to produce another number
- Convert the resulting number to a string

u=0 fails on the first step as there's no such thing as a number rounded to
zero significant digits.  The resulting string is thus undefined.

>>>
>>> Gforth throws exception  -262, but is should not.
>>> sp-forth/4 handles this case correctly.
>>>
>>> Probably, "represent" may return false at the top if u is zero.
>>
>> No.  The logical extrapolation of u approaching zero is that the number
>> is progressively rounded until it is either 0 or 1 according to which was
>> closest.
> 
> "the significand represented as a decimal fraction", so each digit is chosen from {0,1, ..., 9}.

That refers to the resulting number after rounding.  There's no difficulty
representing 1.0 as a fraction and adjusted exponent.

>> Many implementations actually do this internally but screw up at
>> the interface because neither implementer nor ANS knew what u=0 should do.
> 
> It's a problem of particular implementations.

It's a problem if they think ANS wanted them to return an empty string.

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Thread

0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-25 18:25 -0500
  Re: 0 SET-ORDER why? minforth@gmx.net (minforth) - 2024-06-26 01:19 +0000
    Re: 0 SET-ORDER why? albert@spenarnc.xs4all.nl - 2024-06-26 11:12 +0200
    Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-26 05:54 -0500
  Re: 0 SET-ORDER why? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-06-26 07:49 +0000
    Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-06-26 18:50 +1000
      Re: 0 SET-ORDER why? Ruvim <ruvim.pinka@gmail.com> - 2024-06-26 17:36 +0400
        Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-06-27 13:19 +1000
          Re: 0 SET-ORDER why? Gerry Jackson <do-not-use@swldwa.uk> - 2024-06-27 23:10 +0100
            Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-06-28 11:56 +1000
          Re: 0 SET-ORDER why? Ruvim <ruvim.pinka@gmail.com> - 2024-06-28 13:51 +0400
            Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-06-28 22:19 +1000
              Re: 0 SET-ORDER why? Ruvim <ruvim.pinka@gmail.com> - 2024-06-28 17:48 +0400
                Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-06-29 03:08 +1000
                Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-07-01 18:45 +1000
            Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-06-29 13:27 +1000
        Re: 0 SET-ORDER why? Gerry Jackson <do-not-use@swldwa.uk> - 2024-06-27 05:14 +0100
          Re: 0 SET-ORDER why? albert@spenarnc.xs4all.nl - 2024-06-27 11:05 +0200
            Re: 0 SET-ORDER why? minforth@gmx.net (minforth) - 2024-06-27 13:00 +0000
          Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-06-27 22:41 +1000
          Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-27 14:09 -0500
            Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-27 14:22 -0500
              Re: 0 SET-ORDER why? Gerry Jackson <do-not-use@swldwa.uk> - 2024-06-27 23:08 +0100
                Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-27 18:44 -0500
              Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-06-28 15:51 +1000
            Re: 0 SET-ORDER why? albert@spenarnc.xs4all.nl - 2024-06-28 10:04 +0200
              Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-29 09:09 -0500
                Re: 0 SET-ORDER why? albert@spenarnc.xs4all.nl - 2024-06-30 12:22 +0200
          Re: 0 SET-ORDER why? Ruvim <ruvim.pinka@gmail.com> - 2024-06-28 14:20 +0400
            Re: 0 SET-ORDER why? albert@spenarnc.xs4all.nl - 2024-06-28 21:45 +0200
              Recognizer protocol (was: 0 SET-ORDER why?) Ruvim <ruvim.pinka@gmail.com> - 2024-06-29 02:27 +0400
            Re: 0 SET-ORDER why? Gerry Jackson <do-not-use@swldwa.uk> - 2024-07-04 07:26 +0100
    Re: 0 SET-ORDER why? albert@spenarnc.xs4all.nl - 2024-06-26 11:18 +0200
      Re: 0 SET-ORDER why? minforth@gmx.net (minforth) - 2024-06-26 10:36 +0000
      Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-26 06:13 -0500
    Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-26 05:56 -0500
      Re: 0 SET-ORDER why? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-06-28 15:50 +0000
        Re: 0 SET-ORDER why? Hans Bezemer <the.beez.speaks@gmail.com> - 2024-06-28 18:39 +0200
        Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-29 09:17 -0500
          Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-06-30 12:21 +1000
            Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-30 11:10 -0500
              Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-30 11:16 -0500
                Re: 0 SET-ORDER why? minforth@gmx.net (minforth) - 2024-06-30 17:38 +0000
                Re: 0 SET-ORDER why? albert@spenarnc.xs4all.nl - 2024-06-30 20:25 +0200
                Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-30 13:31 -0500
                Re: 0 SET-ORDER why? minforth@gmx.net (minforth) - 2024-06-30 20:37 +0000
                Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-06-30 20:49 -0500
                Re: 0 SET-ORDER why? mhx@iae.nl (mhx) - 2024-07-01 07:06 +0000
                Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-07-01 05:06 -0500
                Re: 0 SET-ORDER why? albert@spenarnc.xs4all.nl - 2024-07-01 13:35 +0200
                Re: 0 SET-ORDER why? Ruvim <ruvim.pinka@gmail.com> - 2024-07-01 13:02 +0400
                Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-07-01 05:13 -0500
                Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-07-01 21:02 +1000
                Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-07-02 15:56 +1000
                Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-07-02 20:04 -0500
                Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-07-03 12:32 +1000
                Re: 0 SET-ORDER why? albert@spenarnc.xs4all.nl - 2024-07-03 11:59 +0200
                Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-07-04 00:46 +1000
                Re: 0 SET-ORDER why? albert@spenarnc.xs4all.nl - 2024-07-01 13:39 +0200
                Re: 0 SET-ORDER why? sjack@dontemail.me (sjack) - 2024-07-02 14:29 +0000
                Re: 0 SET-ORDER why? dxf <dxforth@gmail.com> - 2024-07-03 00:52 +1000
                Re: 0 SET-ORDER why? Ruvim <ruvim.pinka@gmail.com> - 2024-07-02 17:42 +0400
                Re: 0 SET-ORDER why? Krishna Myneni <krishna.myneni@ccreweb.org> - 2024-07-02 20:17 -0500
                Re: 0 SET-ORDER why? Anthony Howe <achowe@snert.com> - 2024-09-21 15:37 -0400
                Re: 0 SET-ORDER why? Ruvim <ruvim.pinka@gmail.com> - 2024-09-22 21:52 +0400
                Re: 0 SET-ORDER why? Anthony Howe <achowe@snert.com> - 2024-09-22 14:02 -0400
                Re: 0 SET-ORDER why? Ruvim <ruvim.pinka@gmail.com> - 2024-09-23 00:21 +0400

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