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Re: Did Lifeware Kill Scryer Prolog CLP(Z) ? (Was: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024])

From Mild Shock <janburse@fastmail.fm>
Newsgroups comp.lang.prolog
Subject Re: Did Lifeware Kill Scryer Prolog CLP(Z) ? (Was: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024])
Date 2024-07-27 11:56 +0200
Message-ID <v82g93$dj8h$1@solani.org> (permalink)
References (1 earlier) <v808tc$cuh7$1@solani.org> <v8091j$cuh7$2@solani.org> <v82eii$di8g$1@solani.org> <v82f3o$e0v3$1@solani.org> <v82g0u$dj50$1@solani.org>

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Hi,

But such a criteria is not satisfied in parsing,
especially if you use the more advanced last call
optimization and not only tail recursion optimization.

As soon as parsing is deterministic, you can
leave behind the string part that you already parsed.
So you would need a special sharing that is kind of

a weak sharing that can free some head part. There is
no such problem of freeing the head part, if you use
proper cons cell based lists for parsing.

But naive substring sharing doesn't work for Prolog.
It will unnecessarely lock the whole string always.
Whereas a cell based parser can drop

already parsed parts.

Bye

Mild Shock schrieb:
> Hi,
> 
> Java had a grace period where it still supported
> sharing through a command line option, but later
> it was ditched completely:
> 
> Restriction: This system property is supported only on Java™ 8. String 
> sharing cannot be enabled on Java 11 and later.
> 
> Start of content that applies only to Java 8 (LTS) Setting this property 
> to true avoids sharing a String object when substring() is used to 
> subset a String beginning from offset zero. Avoiding sharing is 
> compatible with the Oracle HotSpot VM.
> https://www.ibm.com/docs/en/sdk-java-technology/8?topic=options-djavalangstringsubstringnocopy 
> 
> 
> Unfortunately I don't find a document detailing
> the decision. Like some JEP or so. Still searching.
> With substring sharing it was very easy to provoke
> 
> an out of memory error. You could allocate large
> strings. Share a UTF-16 character, i.e. substring of
> length 1, in the middle of the string, and the string
> 
> was not garbage collected anymore. I do not exclude
> that under the hood sharing could be used. But it
> possibly needs to some compilation technique including
> 
> some dedicated analysis that determines that the parent
> string stays reachable, so that the child sharing doesn't
> make the parent string solely reachable, since
> 
> since the parent string is already reachable.
> 
> Bye
> 
> Mild Shock schrieb:
>> Hi,
>>
>> I do not exclude a turn-around possibility
>> for Scryer Prolog. But with errors like this,
>> that are at the core of some ideas behind
>>
>> Scryer Prolog, like the glorious char based
>> double quoted lists, which have special data
>> structure support:
>>
>> ?- [X,Y] = [e,foo], Z is X.
>>     X = e, Y = foo, Z = 2.718281828459045.
>>
>> ?- [X,Y] = [e,f], Z is X.
>>     error(type_error(evaluable,e),(is)/2).
>>
>> But I doubt that any such list/array ideas,
>> especially when they try to share subarrays
>> are even a good idea. Trealla Prolog tries
>>
>> something similar. But initial Java had for
>> example a sharing substring() method. But they
>> abandoned that over the time. So their
>>
>> strings are not sharing anymore, and code that
>> relied on sharing got broken. You can have
>> sharing through other interfaces, but Strings
>>
>> are not anymore sharing. Any idea why?
>>
>> Bye

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Thread

A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024] Mild Shock <janburse@fastmail.fm> - 2024-05-27 19:58 +0200
  Re: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024] Mild Shock <janburse@fastmail.fm> - 2024-05-27 20:01 +0200
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                Re: they shoot themselves into the foot (Re: Good Bye Stack-Overflow) Mild Shock <janburse@fastmail.fm> - 2024-11-15 17:11 +0100
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      Re: Can we trust the Scryer Prolog Gurus? (Was: A harsh wind is blowing into the face of Prolog now… ) Mild Shock <janburse@fastmail.fm> - 2024-07-23 00:42 +0200
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    Re: Did Lifeware Kill Scryer Prolog CLP(Z) ? (Was: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024]) Mild Shock <janburse@fastmail.fm> - 2024-07-26 15:41 +0200
      Re: Did Lifeware Kill Scryer Prolog CLP(Z) ? (Was: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024]) Mild Shock <janburse@fastmail.fm> - 2024-07-27 11:27 +0200
        Re: Did Lifeware Kill Scryer Prolog CLP(Z) ? (Was: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024]) Mild Shock <janburse@fastmail.fm> - 2024-07-27 11:36 +0200
          Re: Did Lifeware Kill Scryer Prolog CLP(Z) ? (Was: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024]) Mild Shock <janburse@fastmail.fm> - 2024-07-27 11:52 +0200
            Re: Did Lifeware Kill Scryer Prolog CLP(Z) ? (Was: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024]) Mild Shock <janburse@fastmail.fm> - 2024-07-27 11:56 +0200
              Re: Did Lifeware Kill Scryer Prolog CLP(Z) ? (Was: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024]) Mild Shock <janburse@fastmail.fm> - 2024-07-27 12:04 +0200
                Re: Did Lifeware Kill Scryer Prolog CLP(Z) ? (Was: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024]) Mild Shock <janburse@fastmail.fm> - 2024-07-27 12:09 +0200
                Re: Did Lifeware Kill Scryer Prolog CLP(Z) ? (Was: A harsh wind is blowing into the face of Prolog now… [FORTRAN / TIOBE Index for May 2024]) Mild Shock <janburse@fastmail.fm> - 2024-07-27 12:54 +0200

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