From Newsgroup: comp.lang.prolog

On 03/01/2025 21:04, Julio Di Egidio wrote:

Partial and tentative:

```
  Functional = Closures/applications, Reduction/canonicity
    /    |
Logical  |   = Predicates/queries, Resolution/subsumption
    \    |
  Imperative = Procedures/invocations, Execution/...
```

And there are two views of that triangle: Logical is the top of the
*ideal* such triangle, along the lines of a universe with Prop on top,
which we can reason with; Imperative is the bottom of a *concrete* such triangle, the bootstrap as well as the final point of application of any concrete system.

And Logical is the constructive (structural) type-theory founding the Functional, where Functional exists for expressivity and modularity
(what else?), plus can be compiled back/down to machine language...

Right?

BTW, there are deficiencies of standard Prolog that are indeed very
annoying, to the point that some invoke for the other way round:

HANSEI / Re-thinking Prolog <https://okmij.org/ftp/kakuritu/logic-programming.html#vs-prolog>

But, besides that I would not put logic in terms of "guessing", I'd
propose we just need a Prolog that doesn't have the self-inflicted
quirks: a strengthened resolution with declarative determinism and
indexing, and a strengthened semantics, of variables and/vs open terms,
with a partial order of terms by subsumption, and unifiability as comparability (a purely structural type system definitionally), i.e.
where a variable is the most general term... Or something like that.

No?

-Julio

--- Synchronet 3.20a-Linux NewsLink 1.114

From Newsgroup: comp.lang.prolog

Hi,

Just a side note, don't let you get distracted.
A side node about the chicken/egg problem, i.e.
without the curry:

- a) Eggs came first, for example Turtles had eggs
Turtles are part of an ancient reptilian
lineage ca 300 million years ago

- b) Chickens came after Turtles
Chickens, on the other hand, are much younger
in comparison, evolved from theropod dinosaurs
around 150 million years ago

Not sure whether this helps. But I think it could help
nevertheless:

- i) Logic Programming is the Egg

- ii) From the Egg Turtles or Chickens can hatch,
its very easy to program functionally or
procdurally in Prolog. Just add small DSLs:

https://en.wikipedia.org/wiki/Domain-specific_language

here is an example of a DSL for array manipulation,
and an implementation of Floyd Warshall algorithm:

:- op(100, yf, []).
:- op(800, fx, new).
:- op(800, fx, let).
:- op(800, fx, if).

warshall(N, D) :-
new D[N,N],
(between(1,N,U), between(1,N,V), let D[U,V] = 999, fail; true),
(edge(U,V,W), let D[U,V] = W, fail; true),
(vertex(V), let D[V,V] = 0, fail; true),
(between(1,N,K),
between(1,N,I),
between(1,N,J),
let H = D[I,K] + D[K,J],
(if D[I,J] > H -> let D[I,J] = H; true),
fail; true).

The definition of the DSL needs only one extension
of Prolog, i.e. nb_setarg/3 (SWI-Prolog) respectively
change_arg/3 (Dogelog Player):

new D[N,M] :-
functor(D, '', N),
D =.. [_|L],
new2(L, M).

new2([], _).
new2([X|L], N) :-
functor(X, '', N),
new2(L, N).

let V = E :- var(V), !,
let2(E,V).
let D[R,C] = E :-
let2(E,V),
arg(R, D, H),
nb_setarg(C, H, V).

let2(D[R,C], V) :- !,
arg(R, D, H),
arg(C, H, V).
let2(E+F, R) :- !,
let2(E, V),
let2(F, W),
R is V+W.
let2(V, V).

if E > F :-
let2(E, V),
let2(F, W),
V > W.

Idiot Prolog systems like Scryer Prolog or Trealla Prolog
refuse to provide such imperative gadgets, which are quite
useful. If you interpret the DSL, its already bleeing fast,

much faster than a pure implementation:

?- time((between(1,1000,_), graph(G),
floyd_warshall(4, G, M), fail; true)).
% 3,803,998 inferences, 0.156 CPU in 0.183 seconds (85% CPU, 24345587 Lips) true.

?- time((between(1,1000,_), warshall(4,D), fail; true)).
% 1,046,998 inferences, 0.062 CPU in 0.062 seconds (100% CPU, 16751968 Lips) true.

If you compile the DSL, you can again an itch more speed:

/* DSL compiled */
?- time((between(1,1000,_), warshall(4,D), fail; true)).
% 336,998 inferences, 0.000 CPU in 0.020 seconds (0% CPU, Infinite Lips)
true.

Bye

Julio Di Egidio schrieb:

On 03/01/2025 21:04, Julio Di Egidio wrote:

Partial and tentative:

```
   Functional = Closures/applications, Reduction/canonicity
     /    |
Logical  |   = Predicates/queries, Resolution/subsumption
     \    |
   Imperative = Procedures/invocations, Execution/...
```

And there are two views of that triangle: Logical is the top of the
*ideal* such triangle, along the lines of a universe with Prop on top,
which we can reason with; Imperative is the bottom of a *concrete*
such triangle, the bootstrap as well as the final point of application
of any concrete system.

And Logical is the constructive (structural) type-theory founding the
Functional, where Functional exists for expressivity and modularity
(what else?), plus can be compiled back/down to machine language...

Right?

BTW, there are deficiencies of standard Prolog that are indeed very annoying, to the point that some invoke for the other way round:

HANSEI / Re-thinking Prolog <https://okmij.org/ftp/kakuritu/logic-programming.html#vs-prolog>

But, besides that I would not put logic in terms of "guessing", I'd
propose we just need a Prolog that doesn't have the self-inflicted
quirks: a strengthened resolution with declarative determinism and
indexing, and a strengthened semantics, of variables and/vs open terms,
with a partial order of terms by subsumption, and unifiability as comparability (a purely structural type system definitionally), i.e.
where a variable is the most general term...  Or something like that.

No?

-Julio

--- Synchronet 3.20a-Linux NewsLink 1.114