/** * @file top.yap * @author VITOR SANTOS COSTA * @date Sat Apr 7 03:14:17 2018 * * @brief top-level implementation plus system booting. * * @addtogroup TopLevel Top-Level and Boot Predicates * @ingroup YAPControl * * [TOC] * * @{ * */ :- '$system_meta_predicates'([gated_call(0, 0, ?, 0), catch(0, ?, 0), log_event(+, :)]). % @pred live % % start a Prolog engine. live :- repeat, yap_flag(verbose, normal), current_source_module(Module, Module), ( Module==user -> true % '$compile_mode'(_,0) ; format(user_error, '[~w]~n', [Module]) ), '$system_catch'('$enter_top_level', Module, Error, '$Error'(Error)). % Start file for yap /* I/O predicates */ /* meaning of flags for '$write' is 1 quote illegal atoms 2 ignore operator declarations 4 output '$VAR'(N) terms as A, B, C, ... 8 use portray(_) */ /* main execution loop */ '$read_toplevel'(Goal, Bindings, Pos) :- '$prompt', catch(read_term(user_input, Goal, [ variable_names(Bindings), syntax_errors(dec10), term_position(Pos), input_closing_blank(true) ]), E, '$handle_toplevel_error'(E)). '$handle_toplevel_error'(syntax_error(_)) :- !, fail. '$handle_toplevel_error'(error(io_error(read, user_input), _)) :- !. '$handle_toplevel_error'(_, E) :- throw(E). % reset alarms when entering top-level. '$enter_top_level' :- '$alarm'(0, 0, _, _), fail. '$enter_top_level' :- '$clean_up_dead_clauses', fail. '$enter_top_level' :- get_value('$top_level_goal', GA), GA\=[], !, set_value('$top_level_goal', []), '$run_atom_goal'(GA), fail. '$enter_top_level' :- flush_output, '$run_toplevel_hooks', prompt1(' ?- '), '$read_toplevel'(Command, Varnames, Pos), '$init_debugger', '$command'(Command, Varnames, Pos, top), current_prolog_flag(break_level, BreakLevel), ( BreakLevel\=0 -> true ; '$pred_exists'(halt(_), user) -> halt(0) ; '$halt'(0) ). '$erase_sets' :- eraseall($), eraseall('$$set'), eraseall('$$one'), eraseall('$reconsulted'), fail. '$erase_sets' :- \+ recorded('$path', _, _), recorda('$path', [], _). '$erase_sets'. '$start_corouts' :- eraseall('$corout'), eraseall('$result'), eraseall('$actual'), fail. '$start_corouts' :- recorda('$actual',main,_), recordz('$corout','$corout'(main,main,'$corout'([],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[])),_Ref), recorda('$result',going,_). % % Hack in case expand_term has created a list of commands. % '$execute_commands'(V,_,_,_,_,Source) :- var(V), !, '$do_error'(instantiation_error,meta_call(Source)). '$execute_commands'([],_,_,_,_,_) :- !. '$execute_commands'([C|Cs],M,VL,Pos,Con,Source) :- !, ( '$system_catch'('$execute_command'(C,M,VL,Pos,Con,Source),prolog,Error,'$LoopError'(Error, Con)), fail ; '$execute_commands'(Cs,M,VL,Pos,Con,Source) ). '$execute_commands'(C,M,VL,Pos,Con,Source) :- '$execute_command'(C,M,VL,Pos,Con,Source). % % % '$execute_command'(C,_,_,_,_,Source) :- var(C), !, '$do_error'(instantiation_error,meta_call(Source)). '$execute_command'(C,_,_,_,_top,Source) :- number(C), !, '$do_error'(type_error(callable,C),meta_call(Source)). '$execute_command'(R,_,_,_,_top,Source) :- db_reference(R), !, '$do_error'(type_error(callable,R),meta_call(Source)). '$execute_command'(end_of_file,_,_,_,_,_) :- !. '$execute_command'(Command,_,_,_,_,_) :- '__NB_getval__'('$if_skip_mode', skip, fail), \+ '$if_directive'(Command), !. '$execute_command'((:-G),M,VL,Pos,Option,_) :- Option \= top, !, % allow user expansion '$expand_term'((:- M:G), O), '$yap_strip_module'(O, NM, NO), ( NO = (:- G1) -> '$process_directive'(G1, Option, NM, VL, Pos) ; '$execute_commands'(G1,NM,VL,Pos,Option,O) ). '$execute_command'((?-G), M, VL, Pos, Option, Source) :- Option \= top, !, '$execute_command'(G, M, VL, Pos, top, Source). '$execute_command'(G, M, VL, Pos, Option, Source) :- '$continue_with_command'(Option, VL, Pos, M:G, Source). '$expand_term'(T,O) :- '$expand_term'(T,top,O). '$expand_term'(T,Con,O) :- catch( '$expand_term0'(T,Con,O), _,( '$reenter_debugger'(exit), fail) ), !. '$expand_term0'(T,consult,O) :- expand_term( T, O). '$expand_term0'(T,reconsult,O) :- expand_term( T, O). '$expand_term0'(T,top,O) :- expand_term( T, T1), !, '$expand_term1'(T1,O). '$expand_term0'(T,_,T). '$expand_term1'(T,O) :- '$expand_meta_call'(T, none, O). '$continue_with_command'(Where,V,'$stream_position'(C,_P,A1,A2,A3),'$source_location'(_F,L):G,Source) :- !, '$continue_with_command'(Where,V,'$stream_position'(C,L,A1,A2,A3),G,Source). '$continue_with_command'(reconsult,V,Pos,G,Source) :- % writeln(G), '$go_compile_clause'(G,V,Pos,reconsult,Source), fail. '$continue_with_command'(consult,V,Pos,G,Source) :- '$go_compile_clause'(G,V,Pos,consult,Source), fail. '$continue_with_command'(top,V,_,G,_) :- '$query'(G,V). %% % @pred '$go_compile_clause'(G,Vs,Pos, Where, Source) is det % % interfaces the loader and the compiler % not 100% compatible with SICStus Prolog, as SICStus Prolog would put % module prefixes all over the place, although unnecessarily so. % % @param [in] _G_ is the clause to compile % @param [in] _Vs_ a list of variables and their name % @param [in] _Pos_ the source-code position % @param [in] _N_ a flag telling whether to add first or last % @param [out] _Source_ the user-tranasformed clause '$go_compile_clause'(G, _Vs, _Pos, Where, Source) :- '$precompile_term'(G, Source, G1), !, '$$compile'(G1, Where, Source, _). '$go_compile_clause'(G,_Vs,_Pos, _Where, _Source) :- throw(error(system, compilation_failed(G))). '$$compile'(C, Where, C0, R) :- '$head_and_body'( C, H, B ), '$yap_strip_module'(H,Mod,H0), ( '$undefined'(H0, Mod) -> '$init_pred'(H0, Mod, Where) ; true ), % writeln(Mod:((H:-B))), '$compile'((H0:-B), Where, C0, Mod, R). '$init_pred'(H, Mod, _Where ) :- recorded('$import','$import'(NM,Mod,NH,H,_,_),RI), % NM \= Mod, functor(NH,N,Ar), print_message(warning,redefine_imported(Mod,NM,Mod:N/Ar)), erase(RI), clause(Mod:H,_,R), erase(R), fail. '$init_pred'(H, Mod, Where ) :- '$init_as_dynamic'(Where), !, functor(H, Na, Ar), '$dynamic'(Na/Ar, Mod). '$init_pred'(_H, _Mod, _Where ). '$init_as_dynamic'( asserta ). '$init_as_dynamic'( assertz ). '$init_as_dynamic'( consult ) :- '__NB_getval__'('$assert_all',on,fail). '$init_as_dynamic'( reconsult ) :- '__NB_getval__'('$assert_all',on,fail). '$check_if_reconsulted'(N,A) :- once(recorded('$reconsulted',N/A,_)), recorded('$reconsulted',X,_), ( X = N/A , !; X = '$', !, fail; fail ). '$inform_as_reconsulted'(N,A) :- recorda('$reconsulted',N/A,_). '$clear_reconsulting' :- recorded('$reconsulted',X,Ref), erase(Ref), X == '$', !, ( recorded('$reconsulting',_,R) -> erase(R) ). '$prompt_alternatives_on'(determinism). /* Executing a query */ '$query'(end_of_file,_). '$query'(G,[]) :- '$prompt_alternatives_on'(OPT), ( OPT = groundness ; OPT = determinism), !, '$yes_no'(G,(?-)). '$query'(G,V) :- ( '$current_module'(M), '$current_choice_point'(CP), '$user_call'(G, M), '$current_choice_point'(NCP), '$delayed_goals'(G, V, Vs, LGs, DCP), '$write_answer'(Vs, LGs, Written), '$write_query_answer_true'(Written), ( yap_flag(prompt_alternatives_on,determinism), CP == NCP, DCP = 0 -> format(user_error, '.~n', []), ! ; '$another', ! ), fail ; '$out_neg_answer' ). '$yes_no'(G,C) :- '$current_module'(M), '$do_yes_no'(G,M), '$delayed_goals'(G, [], NV, LGs, _), '$write_answer'(NV, LGs, Written), ( Written = [] -> !,'$present_answer'(C, true) ; '$another', ! ), fail. '$yes_no'(_,_) :- '$out_neg_answer'. '$add_env_and_fail' :- fail. '$process_answer'(Vs, LGs, Bindings) :- %'$purge_dontcares'(Vs,IVs), '$sort'(Vs, NVs), '$prep_answer_var_by_var'(NVs, LAnsw, LGs), '$name_vars_in_goals'(LAnsw, Vs, Bindings). % % *-> at this point would require compiler support, which does not exist. % '$delayed_goals'(G, V, NV, LGs, NCP) :- ( '$$save_by'(NCP1), attributes:delayed_goals(G, V, NV, LGs), '$clean_ifcp'(NCP1), '$$save_by'(NCP2), NCP is NCP2-NCP1 ; copy_term_nat(V, NV), LGs = [], % term_factorized(V, NV, LGs), NCP = 0 ). '$out_neg_answer' :- print_message( help, false), fail. '$do_yes_no'([X|L], M) :- !, '$csult'([X|L], M). '$do_yes_no'(G, M) :- '$user_call'(G, M). '$write_query_answer_true'([]) :- !, format(user_error,true,[]). '$write_query_answer_true'(_). % % present_answer has three components. First it flushes the streams, % then it presents the goals, and last it shows any goals frozen on % the arguments. % '$present_answer'(_,_):- flush_output, fail. '$present_answer'((?-), Answ) :- current_prolog_flag(break_level, BL ), ( BL \= 0 -> format(user_error, '[~p] ',[BL]) ; true ), current_prolog_flag(toplevel_print_options, Opts), write_term(user_error,Answ,Opts). '$another' :- '$clear_input'(user_input), prompt1(' ? '), get_code(user_input,C), '$do_another'(C). '$do_another'(C) :- ( C=:= ";" -> skip(user_input,10), % '$add_nl_outside_console', fail ; C== 10 -> '$add_nl_outside_console', ( '$undefined'(print_message(_,_),prolog) -> format(user_error,'yes~n', []) ; print_message(help,yes) ) ; C== 13 -> get0(user_input,NC), '$do_another'(NC) ; C== -1 -> halt ; skip(user_input,10), '$ask_again_for_another' ). %'$add_nl_outside_console' :- % '$is_same_tty'(user_input, user_error), !. '$add_nl_outside_console' :- format(user_error,'~n',[]). '$ask_again_for_another' :- format(user_error,'Action (\";\" for more choices, for exit)', []), '$another'. '$write_answer'(_,_,_) :- flush_output, fail. '$write_answer'(Vs, LBlk, FLAnsw) :- '$process_answer'(Vs, LBlk, NLAnsw), '$write_vars_and_goals'(NLAnsw, first, FLAnsw). %% @pred write_query_answer( +Bindings ) % % YAP uses this routine to output the answer to a query. % _Bindings_ are % - unifications % - suspended or floundered goals, representing constraints. % write_query_answer( Bindings ) :- '$write_vars_and_goals'(Bindings, first, _FLAnsw). '$purge_dontcares'([],[]). '$purge_dontcares'([Name=_|Vs],NVs) :- atom_codes(Name, [C|_]), C is "_", !, '$purge_dontcares'(Vs,NVs). '$purge_dontcares'([V|Vs],[V|NVs]) :- '$purge_dontcares'(Vs,NVs). '$prep_answer_var_by_var'([], L, L). '$prep_answer_var_by_var'([Name=Value|L], LF, L0) :- '$delete_identical_answers'(L, Value, NL, Names), '$prep_answer_var'([Name|Names], Value, LF, LI), '$prep_answer_var_by_var'(NL, LI, L0). % fetch all cases that have the same solution. '$delete_identical_answers'([], _, [], []). '$delete_identical_answers'([(Name=Value)|L], Value0, FL, [Name|Names]) :- Value == Value0, !, '$delete_identical_answers'(L, Value0, FL, Names). '$delete_identical_answers'([VV|L], Value0, [VV|FL], Names) :- '$delete_identical_answers'(L, Value0, FL, Names). % now create a list of pairs that will look like goals. '$prep_answer_var'(Names, Value, LF, L0) :- var(Value), !, '$prep_answer_unbound_var'(Names, LF, L0). '$prep_answer_var'(Names, Value, [nonvar(Names,Value)|L0], L0). % ignore unbound variables '$prep_answer_unbound_var'([_], L, L) :- !. '$prep_answer_unbound_var'(Names, [var(Names)|L0], L0). '$gen_name_string'(I,L,[C|L]) :- I < 26, !, C is I+65. '$gen_name_string'(I,L0,LF) :- I1 is I mod 26, I2 is I // 26, C is I1+65, '$gen_name_string'(I2,[C|L0],LF). '$write_vars_and_goals'([], _, []). '$write_vars_and_goals'([nl,G1|LG], First, NG) :- !, nl(user_error), '$write_goal_output'(G1, First, NG, Next, IG), '$write_vars_and_goals'(LG, Next, IG). '$write_vars_and_goals'([G1|LG], First, NG) :- '$write_goal_output'(G1, First, NG, Next, IG), '$write_vars_and_goals'(LG, Next, IG). '$write_goal_output'(var([V|VL]), First, [var([V|VL])|L], next, L) :- !, ( First = first -> true ; format(user_error,',~n',[]) ), format(user_error,'~a',[V]), '$write_output_vars'(VL). '$write_goal_output'(nonvar([V|VL],B), First, [nonvar([V|VL],B)|L], next, L) :- !, ( First = first -> true ; format(user_error,',~n',[]) ), format(user_error,'~a',[V]), '$write_output_vars'(VL), format(user_error,' = ', []), ( yap_flag(toplevel_print_options, Opts) -> write_term(user_error,B,[priority(699)|Opts]) ; write_term(user_error,B,[priority(699)]) ). '$write_goal_output'(nl, First, NG, First, NG) :- !, format(user_error,'~n',[]). '$write_goal_output'(Format-G, First, NG, Next, IG) :- !, G = [_|_], !, % dump on string first so that we can check whether we actually % had any output from the solver. format(string(String),Format,G), ( String == `` -> % we didn't IG = NG, First = Next ; % we did format(user_error, '~N~s', [String]), NG = [G|IG] ). '$write_goal_output'(_-G, First, [G|NG], next, NG) :- !, ( First = first -> true ; format(user_error,',~n',[]) ), ( yap_flag(toplevel_print_options, Opts) -> write_term(user_error,G,Opts) ; format(user_error,'~w',[G]) ). '$write_goal_output'(_M:G, First, [G|NG], next, NG) :- !, ( First = first -> true ; format(user_error,',~n',[]) ), ( yap_flag(toplevel_print_options, Opts) -> write_term(user_error,G,Opts) ; format(user_error,'~w',[G]) ). '$write_goal_output'(G0, First, [M:G|NG], next, NG) :- '$yap_strip_module'(G0,M,G), ( First = first -> true ; format(user_error,',~n',[]) ), ( yap_flag(toplevel_print_options, Opts) -> write_term(user_error,G,Opts) ; format(user_error,'~w',[G]) ). '$name_vars_in_goals'(G, VL0, G) :- '$name_well_known_vars'(VL0), '$variables_in_term'(G, [], GVL), '$name_vars_in_goals1'(GVL, 0, _). '$name_well_known_vars'([]). '$name_well_known_vars'([Name=V|NVL0]) :- var(V), !, V = '$VAR'(Name), '$name_well_known_vars'(NVL0). '$name_well_known_vars'([_|NVL0]) :- '$name_well_known_vars'(NVL0). '$name_vars_in_goals1'([], I, I). '$name_vars_in_goals1'([V|NGVL], I0, IF) :- I is I0+1, '$gen_name_string'(I0,[],SName), !, atom_codes(Name, [95|SName]), V = '$VAR'(Name), '$name_vars_in_goals1'(NGVL, I, IF). '$name_vars_in_goals1'([NV|NGVL], I0, IF) :- nonvar(NV), '$name_vars_in_goals1'(NGVL, I0, IF). '$write_output_vars'([]). '$write_output_vars'([V|VL]) :- format(user_error,' = ~a',[V]), '$write_output_vars'(VL). % % standard meta-call, called if $execute could not do everything. % '$meta_call'(G, M) :- '$current_choice_point'(CP), '$call'(G, CP, G, M). '$user_call'(G, M) :- '$current_choice_point'(CP), gated_call('$start_user_code',M:G,Port,'$reenter_debugger'(Port)). '$cut_by'(CP) :- '$$cut_by'(CP). % % do it in ISO mode. % '$meta_call'(G,_ISO,M) :- '$iso_check_goal'(G,G), '$current_choice_point'(CP), '$call'(G, CP, G, M). '$meta_call'(G, CP, G0, M) :- '$call'(G, CP, G0, M). '$call'(G, CP, G0, _, M) :- /* iso version */ '$iso_check_goal'(G,G0), '$call'(G, CP, G0, M). '$call'(M:G,CP,G0,_M0) :- !, expand_goal(M:G, NG), must_be_callable(NG), '$yap_strip_module'(NG,NM,NC), '$call'(NC,CP,G0,NM). '$call'((X,Y),CP,G0,M) :- !, '$call'(X,CP,G0,M), '$call'(Y,CP,G0,M). '$call'((X->Y),CP,G0,M) :- !, ( '$call'(X,CP,G0,M) -> '$call'(Y,CP,G0,M) ). '$call'((X*->Y),CP,G0,M) :- !, '$call'(X,CP,G0,M), '$call'(Y,CP,G0,M). '$call'((X->Y; Z),CP,G0,M) :- !, ( '$call'(X,CP,G0,M) -> '$call'(Y,CP,G0,M) ; '$call'(Z,CP,G0,M) ). '$call'((X*->Y; Z),CP,G0,M) :- !, ( '$current_choice_point'(DCP), '$call'(X,CP,G0,M), yap_hacks:cut_at(DCP), '$call'(Y,CP,G0,M) ; '$call'(Z,CP,G0,M) ). '$call'((A;B),CP,G0,M) :- !, ( '$call'(A,CP,G0,M) ; '$call'(B,CP,G0,M) ). '$call'((X->Y| Z),CP,G0,M) :- !, ( '$call'(X,CP,G0,M) -> '$call'(Y,CP,G0,M) ; '$call'(Z,CP,G0,M) ). '$call'((X*->Y| Z),CP,G0,M) :- !, ( '$current_choice_point'(DCP), '$call'(X,CP,G0,M), yap_hacks:cut_at(DCP), '$call'(Y,CP,G0,M) ; '$call'(Z,CP,G0,M) ). '$call'((A|B),CP, G0,M) :- !, ( '$call'(A,CP,G0,M) ; '$call'(B,CP,G0,M) ). '$call'(\+ X, _CP, G0, M) :- !, \+ ('$current_choice_point'(CP), '$call'(X,CP,G0,M) ). '$call'(not(X), _CP, G0, M) :- !, \+ ('$current_choice_point'(CP), '$call'(X,CP,G0,M) ). '$call'(!, CP, _G0, _m) :- !, '$$cut_by'(CP). '$call'([X|Y], _, _, M) :- (Y == [] -> consult(M:X) ; '$csult'([X|Y] ,M) ). '$call'(G, _CP, _G0, CurMod) :- % /* % ( % '$is_metapredicate'(G,CurMod) % -> % '$reenter_debugger'(exit)', % ( '$expand_meta_call'(CurMod:G, [], NG) -> true ; true ), % '$enable_debugging' % ; % NG = G % ), % */ '$execute0'(G, CurMod). '$loop'(Stream,exo) :- prolog_flag(agc_margin,Old,0), prompt1(': '), prompt(_,'| '), source_module(OldModule,OldModule), repeat, '$system_catch'(dbload_from_stream(Stream, OldModule, exo), '$db_load', Error, user:'$LoopError'(Error, top)), prolog_flag(agc_margin,_,Old), !. '$loop'(Stream,db) :- prolog_flag(agc_margin,Old,0), prompt1(': '), prompt(_,'| '), source_module(OldModule,OldModule), repeat, '$system_catch'(dbload_from_stream(Stream, OldModule, db), '$db_load', Error, user:'$LoopError'(Error, db) ), prolog_flag(agc_margin,_,Old), !. '$loop'(Stream,Status) :- repeat, '$current_module'( OldModule, OldModule ), '$system_catch'( '$enter_command'(Stream,OldModule,Status), OldModule, Error, user:'$LoopError'(Error, Status) ), !. '$boot_loop'(Stream,Where) :- repeat, source_module( OldModule, OldModule ), read_clause(Stream, Command, [module(OldModule), syntax_errors(dec10),variable_names(_Vars), term_position(_Pos)]), (Command == end_of_file -> ! ; Command = (:- Goal) -> '$system_catch'('$boot_execute'(Goal), prolog, Error, user:'$LoopError'(Error, consult) ), fail ; Command = (H --> B) -> '$system_catch'('$boot_dcg'(H,B, Where), prolog, Error, user:'$LoopError'(Error, consult) ), fail ; '$system_catch'('$boot_clause'( Command, Where ), prolog, Error, user:'$LoopError'(Error, consult) ), fail ). '$boot_execute'( Goal ) :- '$execute'( Goal ), !. '$boot_execute'( Goal ) :- format(user_error, ':- ~w failed.~n', [Goal]). '$boot_dcg'( H, B, Where ) :- '$translate_rule'((H --> B), (NH :- NB) ), '$$compile'((NH :- NB), Where, ( H --> B), _R), !. '$boot_dcg'( H, B, _ ) :- format(user_error, ' ~w --> ~w failed.~n', [H,B]). '$boot_clause'( Command, Where ) :- '$$compile'(Command, Where, Command, _R), !. '$boot_clause'( Command, _ ) :- format(user_error, ' ~w failed.~n', [Command]). '$enter_command'(Stream, Mod, Status) :- prompt1(': '), prompt(_,' '), Options = [module(Mod), syntax_errors(dec10),variable_names(Vars), term_position(Pos)], ( Status == top -> read_term(Stream, Command, Options) ; read_clause(Stream, Command, Options) ), '$command'(Command,Vars,Pos, Status) . /** @pred user:expand_term( _T_,- _X_) is dynamic,multifile. This user-defined predicate is called by YAP after reading goals and clauses. - _Module_:`expand_term(` _T_ , _X_) is called first on the current source module _Module_ ; if i - `user:expand_term(` _T_ , _X_ `)` is available on every module. */ /* General purpose predicates */ '$head_and_body'(M:(H:-B),M:H,M:B) :- !. '$head_and_body'((H:-B),H,B) :- !. '$head_and_body'(H,H,true). gated_call(Setup, Goal, Catcher, Cleanup) :- '$setup_call_catcher_cleanup'(Setup), '$gated_call'( true , Goal, Catcher, Cleanup) . '$gated_call'( All , Goal, Catcher, Cleanup) :- Task0 = cleanup( All, Catcher, Cleanup, Tag, true, CP0), TaskF = cleanup( All, Catcher, Cleanup, Tag, false, CP0), '$tag_cleanup'(CP0, Task0), call( Goal ), '$cleanup_on_exit'(CP0, TaskF). % % split head and body, generate an error if body is unbound. % '$check_head_and_body'(C,M,H,B,_P) :- '$yap_strip_module'(C,M1,(MH:-B0)), !, '$yap_strip_module'(M1:MH,M,H), ( M == M1 -> B = B0 ; B = M1:B0), must_be_callable(M:H). '$check_head_and_body'(MH, M, H, true, _XsP) :- '$yap_strip_module'(MH,M,H), must_be_callable(M:H). % term expansion % % return two arguments: Expanded0 is the term after "USER" expansion. % Expanded is the final expanded term. % '$precompile_term'(Term, ExpandedUser, Expanded) :- %format('[ ~w~n',[Term]), '$expand_clause'(Term, ExpandedUser, ExpandedI), !, %format(' -> ~w~n',[Expanded0]), ( current_prolog_flag(strict_iso, true) /* strict_iso on */ -> Expanded = ExpandedI, '$check_iso_strict_clause'(ExpandedUser) ; '$expand_array_accesses_in_term'(ExpandedI,Expanded) -> true ; Expanded = ExpandedI ). '$precompile_term'(Term, Term, Term). '$expand_clause'(InputCl, C1, CO) :- '$expand_a_clause'( InputCl, C1, CO), !. '$expand_clause'(Cl, Cl, Cl). /** @pred expand_term( _T_,- _X_) This predicate is used by YAP for preprocessing each top level term read when consulting a file and before asserting or executing it. It rewrites a term _T_ to a term _X_ according to the following rules: first try term_expansion/2 in the current module, and then try to use the user defined predicate user:term_expansion/2`. If this call fails then the translating process for DCG rules is applied, together with the arithmetic optimizer whenever the compilation of arithmetic expressions is in progress. */ expand_term(Term,Expanded) :- ( '$do_term_expansion'(Term,Expanded) -> true ; '$expand_term_grammar'(Term,Expanded) ). % % Grammar Rules expansion % '$expand_term_grammar'((A-->B), C) :- prolog:'$translate_rule'((A-->B),C), !. '$expand_term_grammar'(A, A). % % Arithmetic expansion % '$expand_array_accesses_in_term'(Expanded0,ExpandedF) :- '$array_refs_compiled', '$arrays':'$c_arrays'(Expanded0,ExpandedF), !. '$expand_array_accesses_in_term'(Expanded,Expanded). %% @} %% @addtogroup CathThrow Catch and Throw % @ingroup YAPControl % @{ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % catch/throw implementation % at each catch point I need to know: % what is ball; % where was the previous catch /** @pred catch( : _Goal_,+ _Exception_,+ _Action_) is iso The goal `catch( _Goal_, _Exception_, _Action_)` tries to execute goal _Goal_. If during its execution, _Goal_ throws an exception _E'_ and this exception unifies with _Exception_, the exception is considered to be caught and _Action_ is executed. If the exception _E'_ does not unify with _Exception_, control again throws the exception. The top-level of YAP maintains a default exception handler that is responsible to capture uncaught exceptions. */ catch(G, C, A) :- '$catch'(G,C,A). % makes sure we have an environment. '$true'. % system_catch is like catch, but it avoids the overhead of a full % meta-call by calling '$execute0' instead of $execute. % This way it % also avoids module preprocessing and goal_expansion % '$system_catch'(G, M, C, A) :- % check current trail '$catch'(M:G,C,A). '$catch'(MG,_,_) :- '$$save_by'(CP0), '$execute'(MG), '$$save_by'(CP1), % remove catch ( CP0 == CP1 -> ! ; true ). '$catch'(_,C,A) :- '$get_exception'(C0), ( C = C0 -> '$execute_nonstop'(A, prolog) ; throw(C0) ). % variable throws are user-handled. '$run_catch'(G,E) :- var(E), !, call(G ). '$run_catch'(abort,_) :- abort. '$run_catch'('$Error'(E),E) :- !, '$LoopError'(E, top ). '$run_catch'('$LoopError'(E, Where),E) :- !, '$LoopError'(E, Where). '$run_catch'('$TraceError'(E, GoalNumber, G, Module, CalledFromDebugger),E) :- !, '$TraceError'(E, GoalNumber, G, Module, CalledFromDebugger). '$run_catch'(_Signal,E) :- functor( E, N, _), '$hidden_atom'(N), !, throw(E). '$run_catch'( Signal, _E) :- call( Signal ). % % throw has to be *exactly* after system catch! % /** @pred throw(+ _Ball_) is iso The goal `throw( _Ball_)` throws an exception. Execution is stopped, and the exception is sent to the ancestor goals until reaching a matching catch/3, or until reaching top-level. */ '$run_toplevel_hooks' :- current_prolog_flag(break_level, 0 ), recorded('$toplevel_hooks',H,_), H \= fail, !, ( call(user:H) -> true ; true). '$run_toplevel_hooks'. '$run_at_thread_start' :- recorded('$thread_initialization',M:D,_), '$meta_call'(D, M), fail. '$run_at_thread_start'. log_event( String, Args ) :- format( atom( M ), String, Args), log_event( M ). '$prompt' :- current_prolog_flag(break_level, BreakLevel), ( BreakLevel == 0 -> LF = LD ; LF = ['Break (level ', BreakLevel, ')'|LD] ), current_prolog_flag(debug, DBON), ( DBON = true -> ( '$get_debugger_state'( trace,on), ( var(LF) -> LD = ['trace'|LP] ; LD = [', trace '|LP] ) ; (var(LF) -> LD = ['debug'|LP] ; LD = [', debug'|LP] ) ) ; LD = LP ), ( var(LF) -> LP = [P] ; LP = [' ',P] ), yap_flag(toplevel_prompt, P), atomic_concat(LF, PF), prompt1(PF), prompt(_,' | '), '$ensure_prompting'. /** @} */