```
% apply.pl
/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2012, University of Amsterdam
VU University Amsterdam
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
As a special exception, if you link this library with other files,
compiled with a Free Software compiler, to produce an executable, this
library does not by itself cause the resulting executable to be covered
by the GNU General Public License. This exception does not however
invalidate any other reasons why the executable file might be covered by
the GNU General Public License.
*/
:- 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
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
]).
:- use_module(library(error)).
/** <module> Apply predicates on a list
This module defines meta-predicates that apply a predicate on all
members of a list.
@see apply_macros.pl provides compile-time expansion for part of this
library.
@see http://www.cs.otago.ac.nz/staffpriv/ok/pllib.htm
@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, ?, ?, ?, ?),
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 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.
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.
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.
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, [H|L], E, G) :- !,
partition_(T, Pred, L, E, G).
partition_(=, H, Pred, T, L, [H|E], G) :- !,
partition_(T, Pred, L, E, G).
partition_(>, H, Pred, T, L, E, [H|G]) :- !,
partition_(T, Pred, L, E, G).
partition_(Diff, _, _, _, _, _, _) :-
must_be(oneof([<.=,>]), Diff).
/*******************************
* MAPLIST/2... *
*******************************/
%% maplist(:Goal, ?List)
%
% True if Goal can successfully be applied on all elements of
% List. Arguments are reordered to gain performance as well as to
% make the predicate deterministic under normal circumstances.
maplist(Goal, List) :-
maplist_(List, Goal).
maplist_([], _).
maplist_([Elem|Tail], Goal) :-
call(Goal, Elem),
maplist_(Tail, Goal).
%% maplist(:Goal, ?List1, ?List2)
%
% As maplist/2, operating on pairs of elements from two lists.
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)
%
% As maplist/2, operating on triples of elements from three lists.
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)
%
% As maplist/2, operating on quadruples of elements from four
% lists.
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).
/*******************************
* 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 a list, using arguments of the list as left argument. The
% foldl family of predicates is defined by:
%
% ==
% foldl(P, [X11,...,X1n], ..., [Xm1,...,Xmn], V0, Vn) :-
% P(X11, ..., Xm1, V0, V1),
% ...
% P(X1n, ..., Xmn, V', Vn).
% ==
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).
%
% Left scan of list. The scanl family of higher order list
% operations is defined by:
%
% ==
% scanl(P, [X11,...,X1n], ..., [Xm1,...,Xmn], V0,
% [V0,V1,...,Vn]) :-
% P(X11, ..., Xmn, V0, V1),
% ...
% P(X1n, ..., Xmn, V', Vn).
% ==
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).
```