/* 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, [ include/3, % :Pred, +List, -Ok exclude/3, % :Pred. +List, -NotOk partition/4, % :Pred, +List, -Included, -Excluded partition/5, % :Pred, +List, ?Less, ?Equal, ?Greater maplist/2, % :Pred, +List maplist/3, % :Pred, ?List, ?List maplist/4, % :Pred, ?List, ?List, ?List maplist/5, % :Pred, ?List, ?List, ?List, ?List convlist/3, % :Pred, +List, -List foldl/4, % :Pred, +List, ?V0, ?V foldl/5, % :Pred, +List1, +List2, ?V0, ?V foldl/6, % :Pred, +List1, +List2, +List3, ?V0, ?V foldl/7, % :Pred, +List1, +List2, +List3, +List4, % ?V0, ?V scanl/4, % :Pred, +List, ?V0, ?Vs scanl/5, % :Pred, +List1, +List2, ?V0, ?Vs scanl/6, % :Pred, +List1, +List2, +List3, ?V0, ?Vs scanl/7 % :Pred, +List1, +List2, +List3, +List4, % ?V0, ?Vs ]). :- autoload(library(error),[must_be/2]). :- set_prolog_flag(generate_debug_info, false). /** Apply predicates on a list This module defines meta-predicates that apply a predicate on all members of a list. All predicates support partial application in the Goal argument. This means that these calls are identical: ``` ?- maplist(=, [foo, foo], [X, Y]). ?- maplist(=(foo), [X, Y]). ``` @see apply_macros.pl provides compile-time expansion for part of this library. @see http://www.cs.otago.ac.nz/staffpriv/ok/pllib.htm @see Unit test code in src/Tests/library/test_apply.pl @tbd Add include/4, include/5, exclude/4, exclude/5 */ :- meta_predicate include(1, +, -), exclude(1, +, -), partition(1, +, -, -), partition(2, +, -, -, -), maplist(1, ?), maplist(2, ?, ?), maplist(3, ?, ?, ?), maplist(4, ?, ?, ?, ?), convlist(2, +, -), foldl(3, +, +, -), foldl(4, +, +, +, -), foldl(5, +, +, +, +, -), foldl(6, +, +, +, +, +, -), scanl(3, +, +, -), scanl(4, +, +, +, -), scanl(5, +, +, +, +, -), scanl(6, +, +, +, +, +, -). %! include(:Goal, +List1, ?List2) is det. % % Filter elements for which Goal succeeds. True if List2 contains % those elements Xi of List1 for which call(Goal, Xi) succeeds. % % @see exclude/3, partition/4, convlist/3. % @compat Older versions of SWI-Prolog had sublist/3 with the same % arguments and semantics. include(Goal, List, Included) :- include_(List, Goal, Included). include_([], _, []). include_([X1|Xs1], P, Included) :- ( call(P, X1) -> Included = [X1|Included1] ; Included = Included1 ), include_(Xs1, P, Included1). %! exclude(:Goal, +List1, ?List2) is det. % % Filter elements for which Goal fails. True if List2 contains those % elements Xi of List1 for which call(Goal, Xi) fails. % % @see include/3, partition/4 exclude(Goal, List, Included) :- exclude_(List, Goal, Included). exclude_([], _, []). exclude_([X1|Xs1], P, Included) :- ( call(P, X1) -> Included = Included1 ; Included = [X1|Included1] ), exclude_(Xs1, P, Included1). %! partition(:Pred, +List, ?Included, ?Excluded) is det. % % Filter elements of List according to Pred. True if Included % contains all elements for which call(Pred, X) succeeds and % Excluded contains the remaining elements. % % @see include/3, exclude/3, partition/5. partition(Pred, List, Included, Excluded) :- partition_(List, Pred, Included, Excluded). partition_([], _, [], []). partition_([H|T], Pred, Incl, Excl) :- ( call(Pred, H) -> Incl = [H|I], partition_(T, Pred, I, Excl) ; Excl = [H|E], partition_(T, Pred, Incl, E) ). %! partition(:Pred, +List, ?Less, ?Equal, ?Greater) is semidet. % % Filter List according to Pred in three sets. For each element Xi % of List, its destination is determined by call(Pred, Xi, Place), % where Place must be unified to one of =|<|=, =|=|= or =|>|=. % Pred must be deterministic. % % @see partition/4 partition(Pred, List, Less, Equal, Greater) :- partition_(List, Pred, Less, Equal, Greater). partition_([], _, [], [], []). partition_([H|T], Pred, L, E, G) :- call(Pred, H, Diff), partition_(Diff, H, Pred, T, L, E, G). partition_(<, H, Pred, T, L, E, G) :- !, L = [H|Rest], partition_(T, Pred, Rest, E, G). partition_(=, H, Pred, T, L, E, G) :- !, E = [H|Rest], partition_(T, Pred, L, Rest, G). partition_(>, H, Pred, T, L, E, G) :- !, G = [H|Rest], partition_(T, Pred, L, E, Rest). partition_(Diff, _, _, _, _, _, _) :- must_be(oneof([<,=,>]), Diff). /******************************* * MAPLIST * *******************************/ %! maplist(:Goal, ?List1). %! maplist(:Goal, ?List1, ?List2). %! maplist(:Goal, ?List1, ?List2, ?List3). %! maplist(:Goal, ?List1, ?List2, ?List3, ?List4). % % True if Goal is successfully applied on all matching elements of the % list. The maplist family of predicates is defined as: % % ``` % maplist(G, [X_11, ..., X_1n], % [X_21, ..., X_2n], % ..., % [X_m1, ..., X_mn]) :- % call(G, X_11, ..., X_m1), % call(G, X_12, ..., X_m2), % ... % call(G, X_1n, ..., X_mn). % ``` % % This family of predicates is deterministic iff Goal is deterministic % and List1 is a proper list, i.e., a list that ends in `[]`. maplist(Goal, List) :- maplist_(List, Goal). maplist_([], _). maplist_([Elem|Tail], Goal) :- call(Goal, Elem), maplist_(Tail, Goal). maplist(Goal, List1, List2) :- maplist_(List1, List2, Goal). maplist_([], [], _). maplist_([Elem1|Tail1], [Elem2|Tail2], Goal) :- call(Goal, Elem1, Elem2), maplist_(Tail1, Tail2, Goal). maplist(Goal, List1, List2, List3) :- maplist_(List1, List2, List3, Goal). maplist_([], [], [], _). maplist_([Elem1|Tail1], [Elem2|Tail2], [Elem3|Tail3], Goal) :- call(Goal, Elem1, Elem2, Elem3), maplist_(Tail1, Tail2, Tail3, Goal). maplist(Goal, List1, List2, List3, List4) :- maplist_(List1, List2, List3, List4, Goal). maplist_([], [], [], [], _). maplist_([Elem1|Tail1], [Elem2|Tail2], [Elem3|Tail3], [Elem4|Tail4], Goal) :- call(Goal, Elem1, Elem2, Elem3, Elem4), maplist_(Tail1, Tail2, Tail3, Tail4, Goal). %! convlist(:Goal, +ListIn, -ListOut) is det. % % Similar to maplist/3, but elements for which call(Goal, ElemIn, _) % fails are omitted from ListOut. For example (using library(yall)): % % ``` % ?- convlist([X,Y]>>(integer(X), Y is X^2), % [3, 5, foo, 2], L). % L = [9, 25, 4]. % ``` % % @compat Also appears in YAP =|library(maplist)|= and SICStus % =|library(lists)|=. convlist(Goal, ListIn, ListOut) :- convlist_(ListIn, ListOut, Goal). convlist_([], [], _). convlist_([H0|T0], ListOut, Goal) :- ( call(Goal, H0, H) -> ListOut = [H|T], convlist_(T0, T, Goal) ; convlist_(T0, ListOut, Goal) ). /******************************* * FOLDL * *******************************/ %! foldl(:Goal, +List, +V0, -V). %! foldl(:Goal, +List1, +List2, +V0, -V). %! foldl(:Goal, +List1, +List2, +List3, +V0, -V). %! foldl(:Goal, +List1, +List2, +List3, +List4, +V0, -V). % % Fold an ensemble of _m_ (0 <= _m_ <= 4) lists of length _n_ % head-to-tail ("fold-left"), using columns of _m_ list elements as % arguments for Goal. The `foldl` family of predicates is defined as % follows, with `V0` an initial value and `V` the final value of the % folding operation: % % ``` % foldl(G, [X_11, ..., X_1n], % [X_21, ..., X_2n], % ..., % [X_m1, ..., X_mn], V0, V) :- % call(G, X_11, ..., X_m1, V0, V1), % call(G, X_12, ..., X_m2, V1, V2), % ... % call(G, X_1n, ..., X_mn, V, V). % ``` % % No implementation for a corresponding `foldr` is given. A `foldr` % implementation would consist in first calling reverse/2 on each of % the _m_ input lists, then applying the appropriate `foldl`. This is % actually more efficient than using a properly programmed-out % recursive algorithm that cannot be tail-call optimized. foldl(Goal, List, V0, V) :- foldl_(List, Goal, V0, V). foldl_([], _, V, V). foldl_([H|T], Goal, V0, V) :- call(Goal, H, V0, V1), foldl_(T, Goal, V1, V). foldl(Goal, List1, List2, V0, V) :- foldl_(List1, List2, Goal, V0, V). foldl_([], [], _, V, V). foldl_([H1|T1], [H2|T2], Goal, V0, V) :- call(Goal, H1, H2, V0, V1), foldl_(T1, T2, Goal, V1, V). foldl(Goal, List1, List2, List3, V0, V) :- foldl_(List1, List2, List3, Goal, V0, V). foldl_([], [], [], _, V, V). foldl_([H1|T1], [H2|T2], [H3|T3], Goal, V0, V) :- call(Goal, H1, H2, H3, V0, V1), foldl_(T1, T2, T3, Goal, V1, V). foldl(Goal, List1, List2, List3, List4, V0, V) :- foldl_(List1, List2, List3, List4, Goal, V0, V). foldl_([], [], [], [], _, V, V). foldl_([H1|T1], [H2|T2], [H3|T3], [H4|T4], Goal, V0, V) :- call(Goal, H1, H2, H3, H4, V0, V1), foldl_(T1, T2, T3, T4, Goal, V1, V). /******************************* * SCANL * *******************************/ %! scanl(:Goal, +List, +V0, -Values). %! scanl(:Goal, +List1, +List2, +V0, -Values). %! scanl(:Goal, +List1, +List2, +List3, +V0, -Values). %! scanl(:Goal, +List1, +List2, +List3, +List4, +V0, -Values). % % Scan an ensemble of _m_ (0 <= _m_ <= 4) lists of length _n_ % head-to-tail ("scan-left"), using columns of _m_ list elements as % arguments for Goal. The `scanl` family of predicates is defined as % follows, with `V0` an initial value and `V` the final value of the % scanning operation: % % ``` % scanl(G, [X_11, ..., X_1n], % [X_21, ..., X_2n], % ..., % [X_m1, ..., X_mn], V0, [V0, V1, ..., Vn] ) :- % call(G, X_11, ..., X_m1, V0, V1), % call(G, X_12, ..., X_m2, V1, V2), % ... % call(G, X_1n, ..., X_mn, V, Vn). % ``` % % `scanl` behaves like a `foldl` that collects the sequence of % values taken on by the `Vx` accumulator into a list. scanl(Goal, List, V0, [V0|Values]) :- scanl_(List, Goal, V0, Values). scanl_([], _, _, []). scanl_([H|T], Goal, V, [VH|VT]) :- call(Goal, H, V, VH), scanl_(T, Goal, VH, VT). scanl(Goal, List1, List2, V0, [V0|Values]) :- scanl_(List1, List2, Goal, V0, Values). scanl_([], [], _, _, []). scanl_([H1|T1], [H2|T2], Goal, V, [VH|VT]) :- call(Goal, H1, H2, V, VH), scanl_(T1, T2, Goal, VH, VT). scanl(Goal, List1, List2, List3, V0, [V0|Values]) :- scanl_(List1, List2, List3, Goal, V0, Values). scanl_([], [], [], _, _, []). scanl_([H1|T1], [H2|T2], [H3|T3], Goal, V, [VH|VT]) :- call(Goal, H1, H2, H3, V, VH), scanl_(T1, T2, T3, Goal, VH, VT). scanl(Goal, List1, List2, List3, List4, V0, [V0|Values]) :- scanl_(List1, List2, List3, List4, Goal, V0, Values). scanl_([], [], [], [], _, _, []). scanl_([H1|T1], [H2|T2], [H3|T3], [H4|T4], Goal, V, [VH|VT]) :- call(Goal, H1, H2, H3, H4, V, VH), scanl_(T1, T2, T3, T4, Goal, VH, VT). /******************************* * SANDBOX * *******************************/ :- multifile sandbox:safe_meta_predicate/1. safe_api(Name/Arity, sandbox:safe_meta_predicate(apply:Name/Arity)). term_expansion(safe_api, Clauses) :- module_property(apply, exports(API)), maplist(safe_api, API, Clauses). safe_api.