/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (c) 2007-2023, University of Amsterdam VU University Amsterdam SWI-Prolog Solutions b.v. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ :- module(apply_macros, [ expand_phrase/2, % :PhraseGoal, -Goal expand_phrase/4, % :PhraseGoal, +Pos0, -Goal, -Pos apply_macros_sentinel/0 ]). % maplist expansion uses maplist. Do not autoload. :- use_module(library(apply), [maplist/2, maplist/3, maplist/4]). :- use_module(library(yall), [is_lambda/1, lambda_calls/3]). % these may be autoloaded :- autoload(library(lists),[append/3]). :- autoload(library(prolog_code), [mkconj/3, extend_goal/3]). /** Goal expansion rules to avoid meta-calling This module defines goal_expansion/2 rules to deal with commonly used, but fundamentally slow meta-predicates. Notable maplist/2... defines a useful set of predicates, but its execution is considerable slower than a traditional Prolog loop. Using this library calls to maplist/2... are translated into an call to a generated auxiliary predicate that is compiled using compile_aux_clauses/1. Currently this module supports: * maplist/2.. * forall/2 * once/1 * ignore/1 * phrase/2 * phrase/3 * call_dcg/2 * call_dcg/3 The idea for this library originates from ECLiPSe and came to SWI-Prolog through YAP. @tbd Support more predicates @author Jan Wielemaker */ :- create_prolog_flag(optimise_apply, default, [ keep(true), type(oneof([default,false,true])) ]). :- create_prolog_flag(apply_macros_scope, global, [ keep(true), type(oneof([global,imported])) ]). :- dynamic user:goal_expansion/2. :- multifile user:goal_expansion/2. %! expand_maplist(+Callable, +Lists, -Goal) is det. % % Macro expansion for maplist/2 and higher arity. The first clause % deals with code using maplist on fixed lists to reduce typing. Note % that we only expand if all lists have fixed length. In theory we % only need at least one of fixed length, but in that case the goal % expansion instantiates variables in the clause, causing issues with % the remainder of the clause expansion mechanism. expand_maplist(Callable, Lists, Goal) :- maplist(is_list, Lists), maplist(length, Lists, Lens), ( sort(Lens, [Len]) -> Len < 10, unfold_maplist(Lists, Callable, Goal), ! ; Maplist =.. [maplist,Callable|Lists], print_message(warning, maplist(inconsistent_length(Maplist, Lens))), fail ). expand_maplist(Callable0, Lists, Goal) :- length(Lists, N), expand_closure_no_fail(Callable0, N, Callable1), ( Callable1 = _:_ -> strip_module(Callable1, M, Callable), NextGoal = M:NextCall, QPred = M:Pred ; Callable = Callable1, NextGoal = NextCall, QPred = Pred ), Callable =.. [Pred|Args], length(Args, Argc), length(Argv, Argc), length(Vars, N), MapArity is N + 1, format(atom(AuxName), '__aux_maplist/~d_~w+~d', [MapArity, QPred, Argc]), append(Lists, Args, AuxArgs), Goal =.. [AuxName|AuxArgs], AuxArity is N+Argc, prolog_load_context(module, Module), functor(NextCall, Pred, AuxArity), \+ predicate_property(Module:NextGoal, transparent), ( predicate_property(Module:Goal, defined) -> true ; empty_lists(N, BaseLists), length(Anon, Argc), append(BaseLists, Anon, BaseArgs), BaseClause =.. [AuxName|BaseArgs], heads_and_tails(N, NextArgs, Vars, Tails), append(NextArgs, Argv, AllNextArgs), NextHead =.. [AuxName|AllNextArgs], append(Argv, Vars, PredArgs), NextCall =.. [Pred|PredArgs], append(Tails, Argv, IttArgs), NextIterate =.. [AuxName|IttArgs], NextClause = (NextHead :- NextGoal, NextIterate), compile_aux_clauses([BaseClause, NextClause]) ). unfold_maplist(Lists, Callable, Goal) :- maplist(cons, Lists, Heads, Tails), !, maplist_extend_goal(Callable, Heads, G1), unfold_maplist(Tails, Callable, G2), mkconj(G1, G2, Goal). unfold_maplist(_, _, true). cons([H|T], H, T). %! maplist_extend_goal(+Closure, +Args, -Goal) is semidet. % % Extend the maplist Closure with Args. This can be tricky. Notably % library(yall) lambda expressions may instantiate the Closure while % the real execution does not. We can solve that by using % lambda_calls/3. The expand_goal_no_instantiate/2 ensures safe goal % expansion. maplist_extend_goal(Closure, Args, Goal) :- is_lambda(Closure), !, lambda_calls(Closure, Args, Goal1), expand_goal_no_instantiate(Goal1, Goal). maplist_extend_goal(Closure, Args, Goal) :- extend_goal(Closure, Args, Goal1), expand_goal_no_instantiate(Goal1, Goal). % using is_most_general_term/1 is an alternative, but fails % if the goal variables have attributes. expand_goal_no_instantiate(Goal0, Goal) :- term_variables(Goal0, Vars0), expand_goal(Goal0, Goal), term_variables(Goal0, Vars1), Vars0 == Vars1. %! expand_closure_no_fail(+Goal, +Extra:integer, -GoalExt) is det. % % Add Extra additional arguments to Goal. expand_closure_no_fail(Callable0, N, Callable1) :- '$expand_closure'(Callable0, N, Callable1), !. expand_closure_no_fail(Callable, _, Callable). empty_lists(0, []) :- !. empty_lists(N, [[]|T]) :- N2 is N - 1, empty_lists(N2, T). heads_and_tails(0, [], [], []). heads_and_tails(N, [[H|T]|L1], [H|L2], [T|L3]) :- N2 is N - 1, heads_and_tails(N2, L1, L2, L3). %! expand_apply(+GoalIn:callable, -GoalOut) is semidet. % % Macro expansion for `apply' predicates. expand_apply(Maplist, Goal) :- compound(Maplist), compound_name_arity(Maplist, maplist, N), N >= 2, Maplist =.. [maplist, Callable|Lists], qcall_instantiated(Callable), !, expand_maplist(Callable, Lists, Goal). %! expand_apply(+GoalIn:callable, -GoalOut, +PosIn, -PosOut) is semidet. % % Translation of simple meta calls to inline code while % maintaining position information. Note that once(Goal) cannot be % translated to `(Goal->true)` because this will break the % compilation of `(once(X) ; Y)`. A correct translation is to % `(Goal->true;fail)`. Abramo Bagnara suggested % `((Goal->true),true)`, which is both faster and avoids warning % if style_check(+var_branches) is used. expand_apply(forall(Cond, Action), Pos0, Goal, Pos) :- Goal = \+((Cond, \+(Action))), ( nonvar(Pos0), Pos0 = term_position(_,_,_,_,[PosCond,PosAct]) -> Pos = term_position(0,0,0,0, % \+ [ term_position(0,0,0,0, % ,/2 [ PosCond, term_position(0,0,0,0, % \+ [PosAct]) ]) ]) ; true ). expand_apply(once(Once), Pos0, Goal, Pos) :- Goal = (Once->true), ( nonvar(Pos0), Pos0 = term_position(_,_,_,_,[OncePos]), compound(OncePos) -> Pos = term_position(0,0,0,0, % ->/2 [ OncePos, F-T % true ]), arg(2, OncePos, F), % highlight true/false on ")" T is F+1 ; true ). expand_apply(ignore(Ignore), Pos0, Goal, Pos) :- Goal = (Ignore->true;true), ( nonvar(Pos0), Pos0 = term_position(_,_,_,_,[IgnorePos]), compound(IgnorePos) -> Pos = term_position(0,0,0,0, % ;/2 [ term_position(0,0,0,0, % ->/2 [ IgnorePos, F-T % true ]), F-T % true ]), arg(2, IgnorePos, F), % highlight true/false on ")" T is F+1 ; true ). expand_apply(Phrase, Pos0, Expanded, Pos) :- expand_phrase(Phrase, Pos0, Expanded, Pos), !. %! expand_phrase(+PhraseGoal, -Goal) is semidet. %! expand_phrase(+PhraseGoal, +Pos0, -Goal, -Pos) is semidet. % % Provide goal-expansion for PhraseGoal. PhraseGoal is either % phrase/2,3 or call_dcg/2,3. The current version does not % translate control structures, but only simple terminals and % non-terminals. % % For example: % % == % ?- expand_phrase(phrase(("ab", rule)), List), Goal). % Goal = (List=[97, 98|_G121], rule(_G121, [])). % == % % @throws Re-throws errors from dcg_translate_rule/2 expand_phrase(Phrase, Goal) :- expand_phrase(Phrase, _, Goal, _). expand_phrase(phrase(NT,Xs), Pos0, NTXsNil, Pos) :- !, extend_pos(Pos0, 1, Pos1), expand_phrase(phrase(NT,Xs,[]), Pos1, NTXsNil, Pos). expand_phrase(Goal, Pos0, NewGoal, Pos) :- dcg_goal(Goal, NT, Xs0, Xs), nonvar(NT), nt_pos(Pos0, NTPos), dcg_extend(NT, NTPos, NewGoal, Pos, Xs0, Xs). dcg_goal(phrase(NT,Xs0,Xs), NT, Xs0, Xs). dcg_goal(call_dcg(NT,Xs0,Xs), NT, Xs0, Xs). %! dcg_extend(+Callable, +Pos0, -Goal, -Pos, +Xs0, ?Xs) is semidet. dcg_extend(Terminal, Pos0, Xs0 = DList, Pos, Xs0, Xs) :- terminal(Terminal, DList, Xs), !, t_pos(Pos0, Pos). dcg_extend(Q0, Pos0, M:Q, Pos, Xs0, Xs) :- nonvar(Q0), Q0 = M:Q1, !, '$expand':f2_pos(Pos0, MPos, APos0, Pos, MPos, APos), dcg_extend(Q1, APos0, Q, APos, Xs0, Xs). dcg_extend(Control, _, _, _, _, _) :- dcg_control(Control), !, fail. dcg_extend(Compound0, Pos0, Compound, Pos, Xs0, Xs) :- compound(Compound0), !, extend_pos(Pos0, 2, Pos), compound_name_arguments(Compound0, Name, Args0), append(Args0, [Xs0,Xs], Args), compound_name_arguments(Compound, Name, Args). dcg_extend(Name, Pos0, Compound, Pos, Xs0, Xs) :- atom(Name), !, extend_pos(Pos0, 2, Pos), compound_name_arguments(Compound, Name, [Xs0,Xs]). dcg_control(!). dcg_control([]). dcg_control([_|_]). dcg_control({_}). dcg_control((_,_)). dcg_control((_;_)). dcg_control((_->_)). dcg_control((_*->_)). terminal([], DList, Tail) => DList = Tail. terminal(String, DList, Tail), string(String) => string(String), string_codes(String, List), append(List, Tail, DList). terminal(List, DList, Tail), is_list(List) => append(List, Tail, DList). terminal(_, _, _) => fail. extend_pos(Var, _, Var) :- var(Var), !. extend_pos(term_position(F,T,FF,FT,ArgPos0), Extra, term_position(F,T,FF,FT,ArgPos)) :- !, extra_pos(Extra, T, ExtraPos), append(ArgPos0, ExtraPos, ArgPos). extend_pos(FF-FT, Extra, term_position(FF,FT,FF,FT,ArgPos)) :- !, extra_pos(Extra, FT, ArgPos). extra_pos(1, T, [T-T]). extra_pos(2, T, [T-T,T-T]). nt_pos(PhrasePos, _NTPos) :- var(PhrasePos), !. nt_pos(term_position(_,_,_,_,[NTPos|_]), NTPos). t_pos(Pos0, term_position(F,T,F,T,[F-T,F-T])) :- compound(Pos0), !, arg(1, Pos0, F), arg(2, Pos0, T). t_pos(_, _). %! qcall_instantiated(@Term) is semidet. % % True if Term is instantiated sufficiently to call it. % % @tbd Shouldn't this be callable straight away? qcall_instantiated(Var) :- var(Var), !, fail. qcall_instantiated(M:C) :- !, atom(M), callable(C). qcall_instantiated(C) :- callable(C). /******************************* * DEBUGGER * *******************************/ :- multifile prolog_clause:unify_goal/5. prolog_clause:unify_goal(Maplist, Expanded, _Module, Pos0, Pos) :- is_maplist(Maplist), maplist_expansion(Expanded), Pos0 = term_position(F,T,FF,FT,[_MapPos|ArgsPos]), Pos = term_position(F,T,FF,FT,ArgsPos). is_maplist(Goal) :- compound(Goal), compound_name_arity(Goal, maplist, A), A >= 2. maplist_expansion(Expanded) :- compound(Expanded), compound_name_arity(Expanded, Name, _), sub_atom(Name, 0, _, _, '__aux_maplist/'). /******************************* * XREF/COLOUR * *******************************/ :- multifile prolog_colour:vararg_goal_classification/3. prolog_colour:vararg_goal_classification(maplist, Arity, expanded) :- Arity >= 2. /******************************* * ACTIVATE * *******************************/ :- multifile system:goal_expansion/2, system:goal_expansion/4. %! apply_macros_sentinel % % Used to detect that library(apply_macros) is loaded into the current % context explicitly. This test is used if the Prolog flag % `apply_macros` is set to `imported`. apply_macros_sentinel. optimise_apply :- ( current_prolog_flag(optimise_apply, true) -> true ; current_prolog_flag(optimise_apply, default), current_prolog_flag(optimise, true) -> true ). apply_macros :- current_prolog_flag(xref, true), !, fail. apply_macros :- optimise_apply, current_prolog_flag(apply_macros_scope, Scope), apply_macros(Scope). apply_macros(global) => true. apply_macros(imported) => prolog_load_context(module, M), predicate_property(M:apply_macros_sentinel, imported_from(apply_macros)), !. system:goal_expansion(GoalIn, GoalOut) :- apply_macros, expand_apply(GoalIn, GoalOut). system:goal_expansion(GoalIn, PosIn, GoalOut, PosOut) :- apply_macros, expand_apply(GoalIn, PosIn, GoalOut, PosOut). /******************************* * MESSAGES * *******************************/ :- multifile prolog:message//1. prolog:message(maplist(inconsistent_length(Maplist, Lens))) --> { functor(Maplist, _, N) }, [ 'maplist/~d called with proper lists of different lengths (~p) always fails' -[N, Lens] ].