Anything that touches or depends on syntax
is a complete can of worms. The ISO commitee
was not able to find an initial *english natural

language specification wording* for character
look-ahead, so that we find now character
look-ahead in Prolog compounds practially

implemented by all Prolog systems, but character
look-ahead interpretation may differ for
negative numbers, like here:

/* SWI-Prolog */
?- X = - 1^2, write_canonical(X), nl.
-(^(1,2))

/* Scryer Prolog */
?- X = - 1^2, write_canonical(X), nl.
^(-1,2)

But in the case of Scryer Prolog it doesn't
matter, since Scryer Prolog is anyway dead.

Mild Shock schrieb:

I have a question, does SWI-Prolog not anymore use
their dict syntax in the Janus interface:

import janus_swi as janus
janus.query_once("Y is X+1", {"X":1})

{'Y': 2, 'truth': True}

I don’t see _{...} anymore. When and how did this
happen? I was just thinking whether a Syntax
extension PIP is necessary. Such a PIP isn’t listed:

https://prolog-lang.org/ImplementersForum/PIPs.html

Is SWI-Prolog safe, against parsing problems,
when it still has block operators in the
background? Like can one mix and match

code that uses Janus interface with the
“new” dicts with other code that uses the
SWI-Prolog dicts based on _{...}

which we might now term the “old” dicts.
How do you access and manipulate the
“new” dicts, do the “old” operations work?

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

So we have two victims in 2024, two
things died in 2024, are pepsi now:

- Scryer Prolog

- SWI-Prolog Dicts

LoL

Mild Shock schrieb:

Anything that touches or depends on syntax
is a complete can of worms. The ISO commitee
was not able to find an initial *english natural

language specification wording* for character
look-ahead, so that we find now character
look-ahead in Prolog compounds practially

implemented by all Prolog systems, but character
look-ahead interpretation may differ for
negative numbers, like here:

/* SWI-Prolog */
?- X = - 1^2, write_canonical(X), nl.
-(^(1,2))

/* Scryer Prolog */
?- X = - 1^2, write_canonical(X), nl.
^(-1,2)

But in the case of Scryer Prolog it doesn't
matter, since Scryer Prolog is anyway dead.

Mild Shock schrieb:

I have a question, does SWI-Prolog not anymore use
their dict syntax in the Janus interface:

import janus_swi as janus
janus.query_once("Y is X+1", {"X":1})

{'Y': 2, 'truth': True}

I don’t see _{...} anymore. When and how did this
happen? I was just thinking whether a Syntax
extension PIP is necessary. Such a PIP isn’t listed:

https://prolog-lang.org/ImplementersForum/PIPs.html

Is SWI-Prolog safe, against parsing problems,
when it still has block operators in the
background? Like can one mix and match

code that uses Janus interface with the
“new” dicts with other code that uses the
SWI-Prolog dicts based on _{...}

which we might now term the “old” dicts.
How do you access and manipulate the
“new” dicts, do the “old” operations work?

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

import janus_swi as janus
janus.query_once("Y is X+1", {"X":1})

{'Y': 2, 'truth': True}

Ok, my bad the above is Python code and
not Prolog code, right? But how does XSB do it?

Ok the docu say:

Compatibility to the XSB Janus implementation
For this reason we support creating a Python
dict both from a SWI-Prolog dict and from the
Prolog term py({k1:v1, k2:v2, ...}) . https://www.swi-prolog.org/pldoc/man?section=janus-vs-xsb

Does this affirm or reject the need for syntax
extension PIP? Why not just use “new” dicts on
both sides? Forget about the py tag, its anyway
always py. Does XSB “new” dict wrapped

in py compound have access and modification
operations? Wouldn’t it be enough to provide
operations without the py compound wrapping.


Mild Shock schrieb:

So we have two victims in 2024, two
things died in 2024, are pepsi now:

- Scryer Prolog

- SWI-Prolog Dicts

LoL

Mild Shock schrieb:

Anything that touches or depends on syntax
is a complete can of worms. The ISO commitee
was not able to find an initial *english natural

language specification wording* for character
look-ahead, so that we find now character
look-ahead in Prolog compounds practially

implemented by all Prolog systems, but character
look-ahead interpretation may differ for
negative numbers, like here:

/* SWI-Prolog */
?- X = - 1^2, write_canonical(X), nl.
-(^(1,2))

/* Scryer Prolog */
?- X = - 1^2, write_canonical(X), nl.
^(-1,2)

But in the case of Scryer Prolog it doesn't
matter, since Scryer Prolog is anyway dead.

Mild Shock schrieb:

I have a question, does SWI-Prolog not anymore use
their dict syntax in the Janus interface:

import janus_swi as janus
janus.query_once("Y is X+1", {"X":1})

{'Y': 2, 'truth': True}

I don’t see _{...} anymore. When and how did this
happen? I was just thinking whether a Syntax
extension PIP is necessary. Such a PIP isn’t listed:

https://prolog-lang.org/ImplementersForum/PIPs.html

Is SWI-Prolog safe, against parsing problems,
when it still has block operators in the
background? Like can one mix and match

code that uses Janus interface with the
“new” dicts with other code that uses the
SWI-Prolog dicts based on _{...}

which we might now term the “old” dicts.
How do you access and manipulate the
“new” dicts, do the “old” operations work?

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Ok, when I listed these two tomb stones,
this wasn't because I was jealous that
SWI-Prolog has dicts and dicts syntax,

its more the KISS principle, and the idea
that Prolog processors should pursue
non-functional optimizations without

new functional requirements. It might
appear as a strange idea, but it has many
advantages like not affecting the end-user

functionally in any way and not affecting
portability in any way. In as far my
tomb stones wish list is that long:

- SWI-Prolog dicts

- String type [not only SWI-Prolog]

The string type idea made it also into
a few newer Prolog system, but wouldn't it
be nice if strings where just transparent,

and implementation detail the Prolog processor
chooses, and not anything the end-user has
to worry about?

Mild Shock schrieb:

So we have two victims in 2024, two
things died in 2024, are pepsi now:

- Scryer Prolog

- SWI-Prolog Dicts

LoL

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)