This repository has been archived on 2023-08-20. You can view files and clone it, but cannot push or open issues or pull requests.
yap-6.3/pl/utils.yap

764 lines
23 KiB
Plaintext
Raw Normal View History

/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: utils.yap *
* Last rev: 8/2/88 *
* mods: *
* comments: Some utility predicates available in yap *
* *
*************************************************************************/
once(G) :- '$execute'(G), !.
if(X,Y,_Z) :-
CP is '$last_choice_pt',
'$execute'(X),
'$clean_ifcp'(CP),
'$execute'(Y).
if(_X,_Y,Z) :-
'$execute'(Z).
call(X,A) :- '$execute'(X,A).
call(X,A1,A2) :- '$execute'(X,A1,A2).
call(X,A1,A2,A3) :- '$execute'(X,A1,A2,A3).
call_with_args(M:V) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V)).
call_with_args(_:M:A) :- !,
call_with_args(M:A).
call_with_args(M:A) :- !,
'$call_with_args'(A,M).
call_with_args(A) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,M).
call_with_args(A) :-
'$do_error'(type_error(atom,A),call_with_args(A)).
call_with_args(M:V,A1) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V,A1)).
call_with_args(_:M:A,A1) :- !,
call_with_args(M:A,A1).
call_with_args(M:A,A1) :- !,
'$call_with_args'(A,A1,M).
call_with_args(A,A1) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,A1,M).
call_with_args(A,A1) :-
'$do_error'(type_error(atom,A),call_with_args(A,A1)).
call_with_args(M:V,A1,A2) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V,A1,A2)).
call_with_args(_:M:A,A1,A2) :- !,
call_with_args(M:A,A1,A2).
call_with_args(M:A,A1,A2) :- !,
'$call_with_args'(A,A1,A2,M).
call_with_args(A,A1,A2) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,A1,A2,M).
call_with_args(A,A1,A2) :-
'$do_error'(type_error(atom,A),call_with_args(A,A1,A2)).
call_with_args(M:V,A1,A2,A3) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V,A1,A2,A3)).
call_with_args(_:M:A,A1,A2,A3) :- !,
call_with_args(M:A,A1,A2,A3).
call_with_args(M:A,A1,A2,A3) :- !,
'$call_with_args'(A,A1,A2,A3,M).
call_with_args(A,A1,A2,A3) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,A1,A2,A3,M).
call_with_args(A,A1,A2,A3) :-
'$do_error'(type_error(atom,A),call_with_args(A,A1,A2,A3)).
call_with_args(M:V,A1,A2,A3,A4) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V,A1,A2,A3,A4)).
call_with_args(_:M:A,A1,A2,A3,A4) :- !,
call_with_args(M:A,A1,A2,A3,A4).
call_with_args(M:A,A1,A2,A3,A4) :- !,
'$call_with_args'(A,A1,A2,A3,A4,M).
call_with_args(A,A1,A2,A3,A4) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,A1,A2,A3,A4,M).
call_with_args(A,A1,A2,A3,A4) :-
'$do_error'(type_error(atom,A),call_with_args(A,A1,A2,A3,A4)).
call_with_args(M:V,A1,A2,A3,A4,A5) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V,A1,A2,A3,A4,A5)).
call_with_args(_:M:A,A1,A2,A3,A4,A5) :- !,
call_with_args(M:A,A1,A2,A3,A4,A5).
call_with_args(M:A,A1,A2,A3,A4,A5) :- !,
'$call_with_args'(A,A1,A2,A3,A4,A5,M).
call_with_args(A,A1,A2,A3,A4,A5) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,A1,A2,A3,A4,A5,M).
call_with_args(A,A1,A2,A3,A4,A5) :-
'$do_error'(type_error(atom,A),call_with_args(A,A1,A2,A3,A4,A5)).
call_with_args(M:V,A1,A2,A3,A4,A5,A6) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V,A1,A2,A3,A4,A5,A6)).
call_with_args(_:M:A,A1,A2,A3,A4,A5,A6) :- !,
call_with_args(M:A,A1,A2,A3,A4,A5,A6).
call_with_args(M:A,A1,A2,A3,A4,A5,A6) :- !,
'$call_with_args'(A,A1,A2,A3,A4,A5,A6,M).
call_with_args(A,A1,A2,A3,A4,A5,A6) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,A1,A2,A3,A4,A5,A6,M).
call_with_args(A,A1,A2,A3,A4,A5,A6) :-
'$do_error'(type_error(atom,A),call_with_args(A,A1,A2,A3,A4,A5,A6)).
call_with_args(M:V,A1,A2,A3,A4,A5,A6,A7) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V,A1,A2,A3,A4,A5,A6,A7)).
call_with_args(_:M:A,A1,A2,A3,A4,A5,A6,A7) :- !,
call_with_args(M:A,A1,A2,A3,A4,A5,A6,A7).
call_with_args(M:A,A1,A2,A3,A4,A5,A6,A7) :- !,
'$call_with_args'(A,A1,A2,A3,A4,A5,A6,A7,M).
call_with_args(A,A1,A2,A3,A4,A5,A6,A7) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,A1,A2,A3,A4,A5,A6,A7,M).
call_with_args(A,A1,A2,A3,A4,A5,A6,A7) :-
'$do_error'(type_error(atom,A),call_with_args(A,A1,A2,A3,A4,A5,A6,A7)).
call_with_args(M:V,A1,A2,A3,A4,A5,A6,A7,A8) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V,A1,A2,A3,A4,A5,A6,A7,A8)).
call_with_args(_:M:A,A1,A2,A3,A4,A5,A6,A7,A8) :- !,
call_with_args(M:A,A1,A2,A3,A4,A5,A6,A7,A8).
call_with_args(M:A,A1,A2,A3,A4,A5,A6,A7,A8) :- !,
'$call_with_args'(A,A1,A2,A3,A4,A5,A6,A7,A8,M).
call_with_args(A,A1,A2,A3,A4,A5,A6,A7,A8) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,A1,A2,A3,A4,A5,A6,A7,A8,M).
call_with_args(A,A1,A2,A3,A4,A5,A6,A7,A8) :-
'$do_error'(type_error(atom,A),call_with_args(A,A1,A2,A3,A4,A5,A6,A7,A8)).
call_with_args(M:V,A1,A2,A3,A4,A5,A6,A7,A8,A9) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V,A1,A2,A3,A4,A5,A6,A7,A8,A9)).
call_with_args(_:M:A,A1,A2,A3,A4,A5,A6,A7,A8,A9) :- !,
call_with_args(M:A,A1,A2,A3,A4,A5,A6,A7,A8,A9).
call_with_args(M:A,A1,A2,A3,A4,A5,A6,A7,A8,A9) :- !,
'$current_module'(M),
'$call_with_args'(A,A1,A2,A3,A4,A5,A6,A7,A8,A9,M).
call_with_args(A,A1,A2,A3,A4,A5,A6,A7,A8,A9) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,A1,A2,A3,A4,A5,A6,A7,A8,A9,M).
call_with_args(A,A1,A2,A3,A4,A5,A6,A7,A8,A9) :-
'$do_error'(type_error(atom,A),call_with_args(A,A1,A2,A3,A4,A5,A6,A7,A8,A9)).
call_with_args(M:V,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10) :- var(V), !,
'$do_error'(instantiation_error,call_with_args(M:V,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10)).
call_with_args(_:M:A,A1,A2,A3,A4,A5,A6,A7,A8,A10) :- !,
call_with_args(M:A,A1,A2,A3,A4,A5,A6,A7,A8,A10).
call_with_args(M:A,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10) :- !,
'$call_with_args'(A,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,M).
call_with_args(A,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10) :- atom(A), !,
'$current_module'(M),
'$call_with_args'(A,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,M).
call_with_args(A,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10) :-
'$do_error'(type_error(atom,A),call_with_args(A,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10)).
op(P,T,V) :- var(P), !,
'$do_error'(instantiation_error,op(P,T,V)).
op(P,T,V) :- \+integer(P), !,
'$do_error'(type_error(integer,P),op(P,T,V)).
op(P,T,V) :- (P < 0 ; P > 1200), !,
'$do_error'(domain_error(operator_priority,P),op(P,T,V)).
op(P,T,V) :- var(T), !,
'$do_error'(instantiation_error,op(P,T,V)).
op(P,T,V) :- \+atom(T), !,
'$do_error'(type_error(atom,T),op(P,T,V)).
op(P,T,V) :- var(V), !,
'$do_error'(instantiation_error,op(P,T,V)).
op(P,T,V) :-
\+ atom(V), \+ '$check_list_of_operators'(V, op(P,T,V)),
'$do_error'(type_error(list,V),op(P,T,V)).
op(P,T,V) :- '$op2'(P,T,V).
'$check_list_of_operators'(V, T) :- var(V), !,
'$do_error'(instantiation_error,T).
'$check_list_of_operators'([], _).
'$check_list_of_operators'([H|L], T) :-
'$check_if_operator'(H,T),
'$check_list_of_operators'(L, T).
'$check_if_operator'(H,T) :- var(H), !,
'$do_error'(instantiation_error,T).
'$check_if_operator'(H,_) :- atom(H), !.
'$check_if_operator'(H,T) :-
'$do_error'(type_error(atom,H),T).
'$op2'(_,_,[]) :- !.
'$op2'(P,T,[A|L]) :- !, '$op'(P,T,A), '$op2'(P,T,L).
'$op2'(P,T,A) :- atom(A), '$op'(P,T,A).
'$op'(P,T,',') :- !,
'$do_error'(permission_error(modify,operator,','),op(P,T,',')).
'$op'(P,T,A) :- '$opdec'(P,T,A,prolog).
%%% Operating System utilities
unix(V) :- var(V), !,
'$do_error'(instantiation_error,unix(V)).
unix(argv(L)) :- '$is_list_of_atoms'(L,L), !, '$argv'(L).
unix(argv(V)) :-
'$do_error'(type_error(atomic,V),unix(argv(V))).
unix(cd) :- cd('~').
unix(cd(V)) :- var(V), !,
'$do_error'(instantiation_error,unix(cd(V))).
unix(cd(A)) :- atomic(A), !, cd(A).
unix(cd(V)) :-
'$do_error'(type_error(atomic,V),unix(cd(V))).
unix(environ(X,Y)) :- '$do_environ'(X,Y).
unix(getcwd(X)) :- getcwd(X).
unix(shell(V)) :- var(V), !,
'$do_error'(instantiation_error,unix(shell(V))).
unix(shell(A)) :- atom(A), !, '$shell'(A).
unix(shell(V)) :-
'$do_error'(type_error(atomic,V),unix(shell(V))).
unix(system(V)) :- var(V), !,
'$do_error'(instantiation_error,unix(system(V))).
unix(system(A)) :- atom(A), !, system(A).
unix(system(V)) :-
'$do_error'(type_error(atom,V),unix(system(V))).
unix(shell) :- sh.
unix(putenv(X,Y)) :- '$putenv'(X,Y).
'$is_list_of_atoms'(V,_) :- var(V),!.
'$is_list_of_atoms'([],_) :- !.
'$is_list_of_atoms'([H|L],L0) :- !,
'$check_if_head_may_be_atom'(H,L0),
'$is_list_of_atoms'(L,L0).
'$is_list_of_atoms'(H,L0) :-
'$do_error'(type_error(list,H),unix(argv(L0))).
'$check_if_head_may_be_atom'(H,_) :-
var(H), !.
'$check_if_head_may_be_atom'(H,_) :-
atom(H), !.
'$check_if_head_may_be_atom'(H,L0) :-
'$do_error'(type_error(atom,H),unix(argv(L0))).
'$do_environ'(X, Y) :-
var(X), !,
'$do_error'(instantiation_error,unix(environ(X,Y))).
'$do_environ'(X, Y) :- atom(X), !,
'$getenv'(X,Y).
'$do_environ'(X, Y) :-
'$do_error'(type_error(atom,X),unix(environ(X,Y))).
putenv(Na,Val) :-
'$putenv'(Na,Val).
getenv(Na,Val) :-
'$getenv'(Na,Val).
%%% Saving and restoring a computation
save(A) :- var(A), !,
'$do_error'(instantiation_error,save(A)).
save(A) :- atom(A), !, name(A,S), '$save'(S).
save(S) :- '$save'(S).
save(A,_) :- var(A), !,
'$do_error'(instantiation_error,save(A)).
save(A,OUT) :- atom(A), !, name(A,S), '$save'(S,OUT).
save(S,OUT) :- '$save'(S,OUT).
save_program(A) :- var(A), !,
'$do_error'(instantiation_error,save_program(A)).
save_program(A) :- atom(A), !, name(A,S), '$save_program'(S).
save_program(S) :- '$save_program'(S).
save_program(A, G) :- var(A), !,
'$do_error'(instantiation_error,save_program(A,G)).
save_program(A, G) :- var(G), !,
'$do_error'(instantiation_error,save_program(A,G)).
save_program(A, G) :- \+ callable(G), !,
'$do_error'(type_error(callable,G),save_program(A,G)).
save_program(A, G) :-
( atom(A) -> name(A,S) ; A = S),
recorda('$restore_goal',G,R),
'$save_program'(S),
erase(R),
fail.
save_program(_,_).
restore(A) :- var(A), !,
'$do_error'(instantiation_error,restore(A)).
restore(A) :- atom(A), !, name(A,S), '$restore'(S).
restore(S) :- '$restore'(S).
%%% current ....
recordaifnot(K,T,R) :-
recorded(K,T,R), % force non-det binding to R.
'$still_variant'(R,T),
!,
fail.
recordaifnot(K,T,R) :-
recorda(K,T,R).
recordzifnot(K,T,R) :-
recorded(K,T,R),
'$still_variant'(R,T),
!,
fail.
recordzifnot(K,T,R) :-
recordz(K,T,R).
current_atom(A) :- % check
atom(A), !.
current_atom(A) :- % generate
'$current_atom'(A).
current_predicate(A,T) :- var(T), !, % only for the predicate
'$current_module'(M),
'$current_predicate_no_modules'(M,A,T).
current_predicate(A,M:T) :- % module specified
var(M), !,
current_module(M),
M \= prolog,
'$current_predicate_no_modules'(M,A,T).
current_predicate(A,M:T) :- % module specified
nonvar(T),
!,
functor(T,A,_),
'$pred_exists'(T,M).
current_predicate(A,M:T) :- % module specified
!,
'$current_predicate_no_modules'(M,A,T).
current_predicate(A,T) :- % only for the predicate
'$current_module'(M),
'$current_predicate_no_modules'(M,A,T).
current_predicate(F) :- var(F), !, % only for the predicate
'$current_module'(M),
'$current_predicate3'(M,F).
current_predicate(M:F) :- % module specified
var(M), !,
'$current_module'(M),
M \= prolog,
'$current_predicate3'(M,F).
current_predicate(M:F) :- % module specified
!,
'$current_predicate3'(M,F).
current_predicate(S) :- % only for the predicate
'$current_module'(M),
'$current_predicate3'(M,S).
system_predicate(A,P) :-
'$current_predicate_no_modules'(prolog,A,P),
\+ '$hidden'(A).
system_predicate(P) :-
'$current_module'(M),
'$system_predicate'(P,M).
'$current_predicate_no_modules'(M,A,T) :-
'$current_predicate'(M,A,Arity),
functor(T,A,Arity),
'$pred_exists'(T,M).
'$current_predicate3'(M,A/Arity) :- !,
'$current_predicate'(M,A,Arity),
functor(T,A,Arity),
'$pred_exists'(T,M).
'$current_predicate3'(M,BadSpec) :- % only for the predicate
'$do_error'(type_error(predicate_indicator,BadSpec),current_predicate(M:BadSpec)).
current_key(A,K) :-
'$current_predicate'(idb,A,Arity),
functor(K,A,Arity).
current_key(A,K) :-
'$current_immediate_key'(A,K).
%%% The unknown predicate,
% informs about what the user wants to be done when
% there are no clauses for a certain predicate */
unknown(V0,V) :-
'$current_module'(M),
'$unknown'(V0,V,M).
% query mode
'$unknown'(V0,V,_) :- var(V), !,
'$ask_unknown_flag'(V),
V = V0.
% handle modules.
'$unknown'(V0,Mod:Handler,_) :-
'$unknown'(V0,Handler,Mod).
% check if we have one we like.
'$unknown'(_,New,Mod) :-
'$valid_unknown_handler'(New,Mod), fail.
% clean up previous unknown predicate handlers
'$unknown'(Old,New,Mod) :-
recorded('$unknown','$unknown'(_,MyOld),Ref), !,
erase(Ref),
'$cleanup_unknown_handler'(MyOld,Old),
'$new_unknown'(New, Mod).
% store the new one.
'$unknown'(fail,New,Mod) :-
'$new_unknown'(New, Mod).
'$valid_unknown_handler'(V,_) :-
var(V), !,
'$do_error'(instantiation_error,yap_flag(unknown,V)).
'$valid_unknown_handler'(fail,_) :- !.
'$valid_unknown_handler'(error,_) :- !.
'$valid_unknown_handler'(warning,_) :- !.
'$valid_unknown_handler'(S,M) :-
functor(S,_,1),
arg(1,S,A),
var(A),
\+ '$undefined'(S,M),
!.
'$valid_unknown_handler'(S,_) :-
'$do_error'(domain_error(flag_value,unknown+S),yap_flag(unknown,S)).
'$ask_unknown_flag'(Old) :-
recorded('$unknown','$unkonwn'(_,MyOld),_), !,
'$cleanup_unknwon_handler'(MyOld,Old).
'$ask_unknown_flag'(fail).
'$cleanup_unknown_handler'('$unknown_error'(_),error) :- !.
'$cleanup_unknown_handler'('$unknown_warning'(_),warning) :- !.
'$cleanup_unknown_handler'(Handler, Handler).
'$new_unknown'(fail,_) :- !.
'$new_unknown'(error,_) :- !,
recorda('$unknown','$unknown'(P,'$unknown_error'(P)),_).
'$new_unknown'(warning,_) :- !,
recorda('$unknown','$unknown'(P,'$unknown_warning'(P)),_).
'$new_unknown'(X,M) :-
arg(1,X,A),
recorda('$unknown','$unknown'(A,M:X),_).
'$unknown_error'(Mod:Goal) :-
functor(Goal,Name,Arity),
'$program_continuation'(PMod,PName,PAr),
'$do_error'(existence_error(procedure,Name/Arity),context(Mod:Goal,PMod:PName/PAr)).
'$unknown_warning'(Mod:Goal) :-
functor(Goal,Name,Arity),
'$program_continuation'(PMod,PName,PAr),
'$print_message'(error,error(existence_error(procedure,Name/Arity), context(Mod:Goal,PMod:PName/PAr))),
fail.
%%% Some "dirty" predicates
% Only efective if yap compiled with -DDEBUG
% this predicate shows the code produced by the compiler
'$show_code' :- '$debug'(0'f).
grow_heap(X) :- '$grow_heap'(X).
grow_stack(X) :- '$grow_stack'(X).
%
% gc() expects to be called from "call". Make sure it has an
% environment to return to.
%
%garbage_collect :- save(dump), '$gc', save(dump2).
garbage_collect :-
'$gc'.
gc :-
yap_flag(gc,on).
nogc :-
yap_flag(gc,off).
garbage_collect_atoms :-
'$atom_gc'.
'$force_environment_for_gc'.
'$good_list_of_character_codes'(V) :- var(V), !.
'$good_list_of_character_codes'([]).
'$good_list_of_character_codes'([X|L]) :-
'$good_character_code'(X),
'$good_list_of_character_codes'(L).
'$good_character_code'(X) :- var(X), !.
'$good_character_code'(X) :- integer(X), X > -2, X < 256.
atom_concat(X,Y,At) :-
(
nonvar(X), nonvar(Y)
->
atom_concat([X,Y],At)
;
atom(At) ->
atom_length(At,Len),
'$atom_contact_split'(At,0,Len,X,Y)
;
var(At) ->
'$do_error'(instantiation_error,atom_concat(X,Y,At))
;
'$do_error'(type_error(atom,At),atomic_concant(X,Y,At))
).
atomic_concat(X,Y,At) :-
(
nonvar(X), nonvar(Y)
->
atomic_concat([X,Y],At)
;
atom(At) ->
atom_length(At,Len),
'$atom_contact_split'(At,0,Len,X,Y)
;
number(At) ->
number_codes(At,Codes),
'$append'(X0,Y0,Codes),
name(X,X0),
name(Y,Y0)
;
var(At) ->
'$do_error'(instantiation_error,atomic_concat(X,Y,At))
;
'$do_error'(type_error(atomic,At),atomic_concant(X,Y,At))
).
'$atom_contact_split'(At,Len,Len,X,Y) :- !,
'$atom_split'(At,Len,X,Y).
'$atom_contact_split'(At,Len1,_,X,Y) :-
'$atom_split'(At,Len1,X,Y).
'$atom_contact_split'(At,Len1,Len,X,Y) :-
Len2 is Len1+1,
'$atom_contact_split'(At,Len2,Len,X,Y).
sub_atom(At, Bef, Size, After, SubAt) :-
atom(At), !,
atom_codes(At, Atl),
'$sub_atom2'(Bef, Atl, Size, After, SubAt, sub_atom(At, Bef, Size, After, SubAt)).
sub_atom(At, Bef, Size, After, SubAt) :-
var(At), !,
'$do_error'(instantiation_error,sub_atom(At, Bef, Size,After, SubAt)).
sub_atom(At, Bef, Size, After, SubAt) :-
\+ atom(At), !,
'$do_error'(type_error(atom,At),sub_atom(At, Bef, Size,After, SubAt)).
'$sub_atom2'(Bef, Atl, Size, After, SubAt, ErrorTerm) :-
var(Bef), !,
'$sub_atombv'(Bef, Size, After, SubAt, Atl, ErrorTerm).
'$sub_atom2'(Bef, Atl, Size, After, SubAt, ErrorTerm) :-
'$sub_atom_get_subchars'(Bef, Atl, NewAtl),
'$sub_atom3'(Size, After, SubAt, NewAtl, ErrorTerm).
% if SubAt is bound, the rest is deterministic.
'$sub_atom3'(Size, After, SubAt, Atl, ErrorTerm) :-
nonvar(SubAt), !,
'$sub_atom_needs_atom'(SubAt,ErrorTerm),
'$sub_atom_needs_int'(Size,ErrorTerm),
'$sub_atom_needs_int'(After,ErrorTerm),
atom_codes(SubAt,Atls),
'$$_length1'(Atls, 0, Size),
'$sub_atom_get_subchars_and_match'(Size, Atl, Atls, NAtl),
'$$_length1'(NAtl,0,After).
% SubAt is unbound, but Size is bound
'$sub_atom3'(Size, After, SubAt, Atl, ErrorTerm) :-
nonvar(Size), !,
'$sub_atom_needs_int'(Size,ErrorTerm),
'$sub_atom_needs_int'(After,ErrorTerm),
'$sub_atom_get_subchars_and_match'(Size, Atl, SubAts, NAtl),
'$$_length1'(NAtl,0,After),
atom_codes(SubAt,SubAts).
% SubAt and Size are unbound, but After is bound.
'$sub_atom3'(Size, After, SubAt, Atl, ErrorTerm) :-
nonvar(After), !,
'$sub_atom_needs_int'(After,ErrorTerm),
'$sub_atom_get_last_subchars'(Atl,SubAts,After,Total,Size),
Total >= After,
atom_codes(SubAt,SubAts).
% SubAt, Size, and After are unbound.
'$sub_atom3'(Size, After, SubAt, Atl, _) :-
'$$_length1'(Atl,0,Len),
'$sub_atom_split'(Atl,Len,SubAts,Size,_,After),
atom_codes(SubAt,SubAts).
% Bef is unbound, so we've got three hypothesis
% ok: in the best case we just try to find SubAt in the original atom.
'$sub_atombv'(Bef, Size, After, SubAt, Atl, ErrorTerm) :-
nonvar(SubAt), !,
'$sub_atom_needs_atom'(SubAt, ErrorTerm),
atom_codes(SubAt,SubAts),
'$sub_atom_search'(SubAts, Atl, 0, Bef, AfterS),
'$$_length1'(SubAts, 0, Size),
'$$_length1'(AfterS, 0, After).
% ok: in the second best case we just get rid of the tail
'$sub_atombv'(Bef, Size, After, SubAt, Atl, ErrorTerm) :-
nonvar(After), !,
'$sub_atom_needs_int'(After, ErrorTerm),
'$sub_atom_get_last_subchars'(Atl,SubAt0,After,Total,Size0),
Total >= After,
'$sub_atom_split'(SubAt0,Size0,_,Bef,SubAts,Size),
atom_codes(SubAt,SubAts).
% ok: just do everything
'$sub_atombv'(Bef, Size, After, SubAt, Atl, _) :-
'$$_length1'(Atl, 0, Len),
'$sub_atom_split'(Atl,Len,_,Bef,Atls2,Len2),
'$sub_atom_split'(Atls2,Len2,SubAts,Size,_,After),
atom_codes(SubAt,SubAts).
'$sub_atom_search'([], AfterS, BefSize, BefSize, AfterS).
'$sub_atom_search'([C|SubAts], [C|Atl], BefSize, BefSize, AfterS) :-
'$sub_atom_search2'(SubAts, Atl, AfterS).
'$sub_atom_search'([C|SubAts], [_|Atl], BefSize, BefSizeF, AfterS) :-
NBefSize is BefSize+1,
'$sub_atom_search'([C|SubAts], Atl, NBefSize, BefSizeF, AfterS).
'$sub_atom_search2'([], AfterS, AfterS).
'$sub_atom_search2'([C|SubAts], [C|Atl], AfterS) :-
'$sub_atom_search2'(SubAts, Atl, AfterS).
'$sub_atom_get_subchars'(0, Atl, Atl) :- !.
'$sub_atom_get_subchars'(I0, [_|Atl], NAtl) :-
I is I0-1,
'$sub_atom_get_subchars'(I, Atl, NAtl).
'$sub_atom_get_subchars'(0, Atl, [], Atl) :- !.
'$sub_atom_get_subchars'(I0, [C|Atl], [C|L], NAtl) :-
I is I0-1,
'$sub_atom_get_subchars'(I, Atl, L, NAtl).
'$sub_atom_get_subchars_and_match'(0, Atl, [], Atl) :- !.
'$sub_atom_get_subchars_and_match'(I0, [C|Atl], [C|Match], NAtl) :-
I is I0-1,
'$sub_atom_get_subchars_and_match'(I, Atl, Match, NAtl).
'$sub_atom_check_length'([],0).
'$sub_atom_check_length'([_|L],N1) :-
N1 > 0,
N is N1-1,
'$sub_atom_check_length'(L,N).
'$sub_atom_get_last_subchars'([],[],_,0,0).
'$sub_atom_get_last_subchars'([C|Atl],SubAt,After,Total,Size) :-
'$sub_atom_get_last_subchars'(Atl,SubAt0,After,Total0,Size0),
Total is Total0+1,
( Total > After ->
Size is Size0+1, SubAt = [C|SubAt0]
;
Size = Size0, SubAt = SubAt0
).
'$sub_atom_split'(Atl,After,[],0,Atl,After).
'$sub_atom_split'([C|Atl],Len,[C|Atls],Size,NAtl,After) :-
Len1 is Len-1,
'$sub_atom_split'(Atl,Len1,Atls,Size0,NAtl,After),
Size is Size0+1.
'$sub_atom_needs_int'(V,_) :- var(V), !.
'$sub_atom_needs_int'(I,_) :- integer(I), I > 0, !.
'$sub_atom_needs_int'(I,ErrorTerm) :- integer(I), !,
'$do_error'(domain_error(not_less_than_zero,I),ErrorTerm).
'$sub_atom_needs_int'(I,ErrorTerm) :-
'$do_error'(type_error(integer,I),ErrorTerm).
'$sub_atom_needs_atom'(V,_) :- var(V), !.
'$sub_atom_needs_atom'(A,_) :- atom(A), !.
'$sub_atom_needs_atom'(A,ErrorTerm) :-
'$do_error'(type_error(atom,A),ErrorTerm).
'$singletons_in_term'(T,VL) :-
'$variables_in_term'(T,[],V10),
'$sort'(V10, V1),
'$non_singletons_in_term'(T,[],V20),
'$sort'(V20, V2),
'$subtract_lists_of_variables'(V2,V1,VL).
'$subtract_lists_of_variables'([],VL,VL).
'$subtract_lists_of_variables'([_|_],[],[]) :- !.
'$subtract_lists_of_variables'([V1|VL1],[V2|VL2],VL) :-
V1 == V2, !,
'$subtract_lists_of_variables'(VL1,VL2,VL).
'$subtract_lists_of_variables'([V1|VL1],[V2|VL2],[V2|VL]) :-
'$subtract_lists_of_variables'([V1|VL1],VL2,VL).
simple(V) :- var(V), !.
simple(A) :- atom(A), !.
simple(N) :- number(N).
callable(V) :- var(V), !, fail.
callable(V) :- atom(V), !.
callable(V) :- functor(V,_,Ar), Ar > 0.
initialization :-
'$initialisation_goals'.
prolog_initialization(G) :- var(G), !,
'$do_error'(instantiation_error,initialization(G)).
prolog_initialization(T) :- callable(T), !,
'$assert_init'(T).
prolog_initialization(T) :-
'$do_error'(type_error(callable,T),initialization(T)).
'$assert_init'(T) :- recordz('$startup_goal',T,_), fail.
'$assert_init'(_).
version :- '$version'.
version(V) :- var(V), !,
'$do_error'(instantiation_error,version(V)).
version(T) :- atom(T), !, '$assert_version'(T).
version(T) :-
'$do_error'(type_error(atom,T),version(T)).
'$assert_version'(T) :- recordz('$version',T,_), fail.
'$assert_version'(_).
'$set_toplevel_hook'(_) :-
recorded('$toplevel_hooks',_,R),
erase(R),
fail.
'$set_toplevel_hook'(H) :-
recorda('$toplevel_hooks',H,_),
fail.
'$set_toplevel_hook'(_).
halt(X) :- '$halt'(X).
halt :-
'$print_message'(informational, halt),
'$halt'(0).
halt(X) :-
'$halt'(X).
nth_instance(X,Y,Z) :-
nonvar(X), var(Y), var(Z), !,
recorded(X,_,Z),
'$nth_instance'(_,Y,Z).
nth_instance(X,Y,Z) :-
'$nth_instance'(X,Y,Z).
'$run_atom_goal'(GA) :-
'$current_module'(Module),
atom_codes(GA,Gs),
charsio:open_mem_read_stream(Gs, Stream),
( '$system_catch'(read(Stream, G),Module,_,fail) ->
close(Stream)
;
close(Stream),
fail
),
'$system_catch'('$query'(once(G), []),Module,Error,user:'$Error'(Error)).
prolog_current_frame(Env) :-
X is $env.