ANN: Dogelog Runtime, Prolog to the Moon (2021)

[Mostowski Collapse]

Please be patient. A big problem with development can be
burnout. So I am trying to slow down things at the moment.
The ideas are easy to sketch, but implementation can take 

weeks. Here is the idea again in a nutshell: use ast.parse()
and compile(). Or build directly an AST, not using the string
detour as in ast.parse(). How long will it take to have a 

working solution? 11 years ago there was:

Pyrolog: Prolog written in Python using PyPy's RPython tool chain
https://www.reddit.com/r/prolog/comments/fbuz1/pyrolog_prolog_written_in_python_using_pypys/

RPython is a framework for implementing interpreters and virtual 
machines for programming languages, especially dynamic languages.
https://rpython.readthedocs.io/en/latest/faq.html

Currently I am not planning to use RPython, want to to use 
standard Python AST and compile(). Might have a look at
RPython or similar stuff later.

Mostowski Collapse schrieb am Sonntag, 19. September 2021 um 22:02:41 UTC+2:
> Also I nowhere wrote that I would use doubly-linked list or 
> a set of objects. The trail is neither, its a single linked list. I 
> also refer directly to objects, I do not need the trail to refer 
> 
> to objects. The Prolog trail is only a logbook. The Prolog trail 
> has similarity to a database log: 
> 
> transaction journal, database log, binary log or audit **trail** 
> https://en.wikipedia.org/wiki/Transaction_log 
> 
> Do you say Python should not be used to implement 
> such things? In my opinion, Python has a high potential 
> to implement Prolog, because it has also ast.parse() 
> 
> and compile(). But I do not yet have a showcase that uses 
> these features of Python to compile Prolog. I dont work 24/7 
> and I cannot clone myself. Currently the Prolog code is interpreted. 
> 
> I have a prototype where Prolog code is compiled into JavaScript, 
> but I did not yet try this approach with Python. Here you see how 
> JavaScript closures are generated, a first prototype: 
> 
> const alt4 = make_defined([new Clause(1, [0, 0], function( 
> display, actual, cont) {return(new Compound(".", [new Compound( 
> "==", [deref(actual.args[0]), "end_of_file"]), new Compound( 
> ".", [new Compound("$CUT", [deref(display[0])]), cont 
> ])]))}, 0, undefined), new Clause(1, [0, 0], function( 
> display, actual, cont) {return(new Compound(".", [new Compound( 
> "expand_include", [deref(actual.args[0]), deref(actual.args[1] 
> ), display[0] = new Variable()]), new Compound(".", 
> [new Compound("handle_term", [deref(display[0])]), new Compound( 
> ".", ["fail", cont])])]))}, -1, undefined)]); 
> 
> add("next_term", 1, new Clause(2, [0], function(display, actual, 
> cont) {return(new Compound(".", [new Compound("read_term", 
> [deref(actual.args[0]), display[0] = new Variable(), 
> new Compound(".", [new Compound("variable_names", [ 
> display[1] = new Variable()]), "[]"])]), new Compound( 
> ".", [new Compound(alt4, [deref(display[0]), deref( 
> display[1])]), cont])]))}, -1, undefined)); 
> 
> https://github.com/jburse/dogelog-moon/issues/184 
> 
> Will do the same for Python in the next weeks. Then later this approach 
> will be combined with a few planned optimizations. So far got a 25% 
> speed increase for JavaScript with this new compilation scheme, but 
> 
> there is no official release out yet, that features this approach. And 
> there should be much more in it, also for Python.
> Mostowski Collapse schrieb am Sonntag, 19. September 2021 um 21:46:20 UTC+2: 
> > sympy also builds a language on top of Python. 
> > pandas also builds a language on top of Python. 
> > 
> > Is there some pope that says this wouldn't be 
> > allowed, I dont think so, otherwise sympy, pandas, etc.. 
> > 
> > wouldn't exist. I dont understand your argument. 
> > 
> > Chris Angelico schrieb: 
> > > On Mon, Sep 20, 2021 at 3:19 AM Mostowski Collapse <janb... at fastmail.fm> wrote: 
> > >> 
> > >> I am refering to: 
> > >> 
> > >> Greg Ewing schrieb: 
> > >> > where [w] is a weak reference object. Then you could periodically 
> > >> > scan the trail looking for dead weakref objects and remove the 
> > >> > corresponding [*] node from the list. 
> > >> > 
> > >> > You can also attach callbacks to weakref objects that are triggered 
> > >> > when the referenced object dies. You might be able to make use of 
> > >> > that to remove items from the trail instead of the periodic scanning. 
> > >> 
> > >> Question to Chris Angelico: If I stay with my 
> > >> sweep_trail(), which is the periodically scanning, 
> > >> I can use a single linked list. 
> > >> 
> > >> On the other hand if I would use the trigger 
> > >> from Python, I possibly would need a double linked 
> > >> list, to remove an element. 
> > >> 
> > >> Chris Angelico, is there a third option, that I have 
> > >> overlooked? Single linked list uses less space 
> > >> than double linked list, this why I go with scan. 
> > >> 
> > > 
> > > I don't know. I don't understand your code well enough to offer advice 
> > > like that, because *your code is too complicated* and not nearly clear 
> > > enough. 
> > > 
> > > But however it is that you're doing things, the best way is almost 
> > > always to directly refer to objects. Don't fiddle around with creating 
> > > your own concept of a doubly-linked list and a set of objects; just 
> > > refer directly to the objects. Let Python be Python, don't try to 
> > > build your own language on top of it. 
> > > 
> > > ChrisA 
> > >