Files
scryer-prolog/src/prolog/lib/builtins.pl
2018-09-26 19:33:27 -06:00

313 lines
11 KiB
Prolog

:- op(400, yfx, /).
:- module(builtins, [(=)/2, (+)/2, (**)/2, (*)/2, (-)/2, (/)/2,
(/\)/2, (\/)/2, (is)/2, (xor)/2, (div)/2, (//)/2, (rdiv)/2,
(<<)/2, (>>)/2, (mod)/2, (rem)/2, (>)/2, (<)/2, (=\=)/2,
(=:=)/2, (-)/1, (>=)/2, (=<)/2, (,)/2, (->)/2, (;)/2, (=..)/2,
(==)/2, (\==)/2, (@=<)/2, (@>=)/2, (@<)/2, (@>)/2, (=@=)/2,
(\=@=)/2, (:)/2, call_with_inference_limit/3, catch/3,
current_prolog_flag/2, set_prolog_flag/2,
setup_call_cleanup/3, term_variables/2, throw/1, true/0,
false/0]).
/* this is an implementation specific declarative operator used to implement call_with_inference_limit/3
and setup_call_cleanup/3. switches to the default trust_me and retry_me_else. Indexing choice
instructions are unchanged. */
:- op(700, fx, non_counted_backtracking).
% arithmetic operators.
:- op(700, xfx, is).
:- op(500, yfx, +).
:- op(500, yfx, -).
:- op(400, yfx, *).
:- op(200, xfy, **).
:- op(500, yfx, /\).
:- op(500, yfx, \/).
:- op(500, yfx, xor).
:- op(400, yfx, div).
:- op(400, yfx, //).
:- op(400, yfx, rdiv).
:- op(400, yfx, <<).
:- op(400, yfx, >>).
:- op(400, yfx, mod).
:- op(400, yfx, rem).
:- op(200, fy, -).
% arithmetic comparison operators.
:- op(700, xfx, >).
:- op(700, xfx, <).
:- op(700, xfx, =\=).
:- op(700, xfx, =:=).
:- op(700, xfx, >=).
:- op(700, xfx, =<).
% control.
:- op(700, xfx, =).
:- op(900, fy, \+).
:- op(700, xfx, =..).
% conditional operators.
:- op(1050, xfy, ->).
:- op(1100, xfy, ;).
% term comparison.
:- op(700, xfx, ==).
:- op(700, xfx, \==).
:- op(700, xfx, @=<).
:- op(700, xfx, @>=).
:- op(700, xfx, @<).
:- op(700, xfx, @>).
:- op(700, xfx, =@=).
:- op(700, xfx, \=@=).
% module resolution operator.
:- op(600, xfy, :).
% the maximum arity flag. needs to be replaced with current_prolog_flag(max_arity, MAX_ARITY).
max_arity(63).
% unify.
X = X.
true.
false :- '$fail'.
% flags.
current_prolog_flag(Flag, false) :- Flag == bounded, !.
current_prolog_flag(bounded, false).
current_prolog_flag(Flag, down) :- Flag == integer_rounding_function, !.
current_prolog_flag(integer_rounding_function, down).
current_prolog_flag(Flag, Value) :- Flag == double_quotes, !, '$get_double_quotes'(Value).
current_prolog_flag(double_quotes, Value) :- '$get_double_quotes'(Value).
current_prolog_flag(Flag, _) :- Flag == max_integer, !, '$fail'.
current_prolog_flag(Flag, _) :- Flag == min_integer, !, '$fail'.
current_prolog_flag(Flag, _) :-
atom(Flag),
throw(error(domain_error(prolog_flag, Flag), current_prolog_flag/2)). % 8.17.2.3 b
current_prolog_flag(Flag, _) :-
nonvar(Flag),
throw(error(type_error(atom, Flag), current_prolog_flag/2)). % 8.17.2.3 a
set_prolog_flag(Flag, Value) :-
(var(Flag) ; var(Value)),
throw(error(instantiation_error, set_prolog_flag/2)). % 8.17.1.3 a, b
set_prolog_flag(bounded, false) :- !. % 7.11.1.1
set_prolog_flag(bounded, true) :- !, '$fail'. % 7.11.1.1
set_prolog_flag(bounded, Value) :-
throw(error(domain_error(flag_value, bounded + Value), set_prolog_flag/2)). % 8.17.1.3 e
set_prolog_flag(max_integer, Value) :- integer(Value), !, '$fail'. % 7.11.1.2
set_prolog_flag(max_integer, Value) :-
throw(error(domain_error(flag_value, max_integer + Value), set_prolog_flag/2)). % 8.17.1.3 e
set_prolog_flag(min_integer, Value) :- integer(Value), !, '$fail'. % 7.11.1.3
set_prolog_flag(min_integer, Value) :-
throw(error(domain_error(flag_value, min_integer + Value), set_prolog_flag/2)). % 8.17.1.3 e
set_prolog_flag(integer_rounding_function, down) :- !. % 7.11.1.4
set_prolog_flag(integer_rounding_function, Value) :-
throw(error(domain_error(flag_value, integer_rounding_function + Value),
set_prolog_flag/2)). % 8.17.1.3 e
set_prolog_flag(double_quotes, chars) :-
!, '$set_double_quotes'(chars). % 7.11.2.5, list of one-char atoms.
set_prolog_flag(double_quotes, atom) :-
!, '$set_double_quotes'(atom). % 7.11.2.5, list of one-char atoms.
set_prolog_flag(double_quotes, Value) :-
throw(error(domain_error(flag_value, double_quotes + Value),
set_prolog_flag/2)). % 8.17.1.3 e
set_prolog_flag(Flag, _) :-
atom(Flag),
throw(error(domain_error(prolog_flag, Flag), set_prolog_flag/2)). % 8.17.1.3 d
set_prolog_flag(Flag, _) :-
throw(error(type_error(atom, Flag), set_prolog_flag/2)). % 8.17.1.3 c
% control operators.
','(G1, G2) :- '$get_b_value'(B), '$call_with_default_policy'(comma_errors(G1, G2, B)).
:- non_counted_backtracking comma_errors/3.
comma_errors(G1, G2, B) :- var(G1), throw(error(instantiation_error, (,)/2)).
comma_errors(G1, G2, B) :- '$call_with_default_policy'(','(G1, G2, B)).
:- non_counted_backtracking (,)/3.
','(!, CF, B) :- compound(CF),
'$call_with_default_policy'(CF = ','(G1, G2)),
'$set_cp'(B),
'$call_with_default_policy'(comma_errors(G1, G2, B)).
','(!, Atom, B) :- Atom == !, '$set_cp'(B).
','(!, G, B) :- '$set_cp'(B), G.
','(G, CF, B) :- compound(CF),
'$call_with_default_policy'(CF = ','(G1, G2)), !, G,
'$call_with_default_policy'(comma_errors(G1, G2, B)).
','(G, Atom, B) :- Atom == !, !, G, '$set_cp'(B).
','(G1, G2, _) :- G1, G2.
;(G1, G2) :- '$get_b_value'(B), ;(G1, G2, B).
:- non_counted_backtracking (;)/3.
;(G1, G4, B) :- compound(G1),
'$call_with_default_policy'(G1 = ->(G2, G3)),
(G2 -> G3 ; '$set_cp'(B), G4).
;(G1, G2, B) :- G1 == !, '$set_cp'(B), G2.
;(G1, G2, B) :- G2 == !, G1, '$set_cp'(B).
;(G, _, _) :- G.
;(_, G, _) :- G.
G1 -> G2 :- '$get_b_value'(B), '$call_with_default_policy'(->(G1, G2, B)).
:- non_counted_backtracking (->)/3.
->(G1, G2, B) :- G2 == !, G1, '$set_cp'(B).
->(G1, G2, B) :- G1, '$set_cp'(B), G2.
% univ.
\+ G :- G, !, false.
\+ _.
:- non_counted_backtracking univ_errors/3.
univ_errors(Term, List, N) :-
'$skip_max_list'(N, -1, List, R),
( var(R) -> ( var(Term), throw(error(instantiation_error, (=..)/2)) % 8.5.3.3 a)
; true )
; R \== [] -> throw(error(type_error(list, List), (=..)/2)) % 8.5.3.3 b)
; List = [H|T] -> ( var(H), var(Term), % R == [] => List is a proper list.
throw(error(instantiation_error, (=..)/2)) % 8.5.3.3 c)
; T \== [], nonvar(H), \+ atom(H),
throw(error(type_error(atom, H), (=..)/2)) % 8.5.3.3 d)
; compound(H), T == [],
throw(error(type_error(atomic, H), (=..)/2)) % 8.5.3.3 e)
; var(Term), max_arity(M), N - 1 > M,
throw(error(representation_error(max_arity), (=..)/2)) % 8.5.3.3 g)
; true )
; var(Term) -> throw(error(domain_error(non_empty_list, List), (=..)/2)) % 8.5.3.3 f)
; true ).
Term =.. List :- '$call_with_default_policy'(univ_errors(Term, List, N)),
'$call_with_default_policy'(univ_worker(Term, List, N)).
:- non_counted_backtracking univ_worker/3.
univ_worker(Term, List, _) :- atomic(Term), !, '$call_with_default_policy'(List = [Term]).
univ_worker(Term, [Name|Args], N) :-
var(Term), !,
'$call_with_default_policy'(Arity is N-1),
'$call_with_default_policy'(functor(Term, Name, Arity)),
'$call_with_default_policy'(get_args(Args, Term, 1, Arity)).
univ_worker(Term, List, _) :-
'$call_with_default_policy'(functor(Term, Name, Arity)),
'$call_with_default_policy'(get_args(Args, Term, 1, Arity)),
'$call_with_default_policy'(List = [Name|Args]).
:- non_counted_backtracking get_args/4.
get_args(Args, _, _, 0) :-
!, '$call_with_default_policy'(Args = []).
get_args([Arg], Func, N, N) :-
!, '$call_with_default_policy'(arg(N, Func, Arg)).
get_args([Arg|Args], Func, I0, N) :-
'$call_with_default_policy'(arg(I0, Func, Arg)),
'$call_with_default_policy'(I1 is I0 + 1),
'$call_with_default_policy'(get_args(Args, Func, I1, N)).
term_variables(Term, Vars) :- '$term_variables'(Term, Vars).
% setup_call_cleanup.
setup_call_cleanup(S, G, C) :- '$get_b_value'(B),
S, '$set_cp_by_default'(B), '$get_current_block'(Bb),
( '$call_with_default_policy'(var(C)) -> throw(error(instantiation_error, setup_call_cleanup/3))
; '$call_with_default_policy'(scc_helper(C, G, Bb)) ).
:- non_counted_backtracking scc_helper/3.
scc_helper(C, G, Bb) :-
'$get_cp'(Cp), '$install_scc_cleaner'(C, NBb), call(G),
( '$check_cp'(Cp) -> '$reset_block'(Bb),
'$call_with_default_policy'(run_cleaners_without_handling(Cp))
; '$call_with_default_policy'(true)
; '$reset_block'(NBb), '$fail').
scc_helper(_, _, Bb) :-
'$reset_block'(Bb), '$get_ball'(Ball),
'$call_with_default_policy'(run_cleaners_with_handling),
'$erase_ball',
'$call_with_default_policy'(throw(Ball)).
scc_helper(_, _, _) :-
'$get_cp'(Cp),
'$call_with_default_policy'(run_cleaners_without_handling(Cp)),
'$fail'.
:- non_counted_backtracking run_cleaners_with_handling/0.
run_cleaners_with_handling :-
'$get_scc_cleaner'(C), '$get_level'(B),
'$call_with_default_policy'(catch(C, _, true)),
'$set_cp_by_default'(B),
'$call_with_default_policy'(run_cleaners_with_handling).
run_cleaners_with_handling :-
'$restore_cut_policy'.
:- non_counted_backtracking run_cleaners_without_handling/1.
run_cleaners_without_handling(Cp) :-
'$get_scc_cleaner'(C), '$get_level'(B), C, '$set_cp_by_default'(B),
'$call_with_default_policy'(run_cleaners_without_handling(Cp)).
run_cleaners_without_handling(Cp) :-
'$set_cp_by_default'(Cp), '$restore_cut_policy'.
% call_with_inference_limit
call_with_inference_limit(G, L, R) :-
'$get_current_block'(Bb),
'$get_b_value'(B),
'$call_with_default_policy'(call_with_inference_limit(G, L, R, Bb, B)),
'$remove_call_policy_check'(B).
:- non_counted_backtracking call_with_inference_limit/5.
call_with_inference_limit(G, L, R, Bb, B) :-
'$install_new_block'(NBb),
'$install_inference_counter'(B, L, Count0),
call(G),
'$inference_level'(R, B),
'$remove_inference_counter'(B, Count1),
'$call_with_default_policy'(is(Diff, L - (Count1 - Count0))),
'$call_with_default_policy'(end_block(B, Bb, NBb, Diff)).
call_with_inference_limit(_, _, R, Bb, B) :-
'$reset_block'(Bb),
'$remove_inference_counter'(B, _),
( '$get_ball'(Ball), '$get_level'(Cp), '$set_cp_by_default'(Cp)
; '$remove_call_policy_check'(B), '$fail' ),
'$erase_ball',
'$call_with_default_policy'(handle_ile(B, Ball, R)).
:- non_counted_backtracking end_block/4.
end_block(_, Bb, NBb, L) :-
'$clean_up_block'(NBb),
'$reset_block'(Bb).
end_block(B, Bb, NBb, L) :-
'$install_inference_counter'(B, L, _),
'$reset_block'(NBb),
'$fail'.
:- non_counted_backtracking handle_ile/3.
handle_ile(B, inference_limit_exceeded(B), inference_limit_exceeded) :- !.
handle_ile(B, E, _) :-
'$remove_call_policy_check'(B),
'$call_with_default_policy'(throw(E)).
% exceptions.
catch(G,C,R) :- '$get_current_block'(Bb), '$call_with_default_policy'(catch(G,C,R,Bb)).
:- non_counted_backtracking catch/4.
catch(G,C,R,Bb) :-
'$install_new_block'(NBb), call(G),
'$call_with_default_policy'(end_block(Bb, NBb)).
catch(G,C,R,Bb) :-
'$reset_block'(Bb),
'$get_ball'(Ball),
'$call_with_default_policy'(handle_ball(Ball, C, R)).
:- non_counted_backtracking end_block/2.
end_block(Bb, NBb) :- '$clean_up_block'(NBb), '$reset_block'(Bb).
end_block(Bb, NBb) :- '$reset_block'(NBb), '$fail'.
:- non_counted_backtracking handle_ball/3.
handle_ball(C, C, R) :- !, '$erase_ball', call(R).
handle_ball(_, _, _) :- '$unwind_stack'.
throw(Ball) :- '$set_ball'(Ball), '$unwind_stack'.