A.2 library(apply): Apply predicates on a list

See also

- apply_macros.pl provides compile-time expansion for part of this library.
- http://www.cs.otago.ac.nz/staffpriv/ok/pllib.htm

To be done

Add include/4, include/5, exclude/4, exclude/5

This module defines meta-predicates that apply a predicate on all members of a list.

[det]include(:Goal, +List1, ?List2)

Filter elements for which Goal succeeds. True if List2 contains those elements Xi of List1 for which call(Goal, Xi) succeeds.

See also

Older versions of SWI-Prolog had sublist/3 with the same arguments and semantics.

[det]exclude(:Goal, +List1, ?List2)

Filter elements for which Goal fails. True if List2 contains those elements Xi of List1 for which call(Goal, Xi) fails.

[det]partition(:Pred, +List, ?Included, ?Excluded)

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.

[semidet]partition(:Pred, +List, ?Less, ?Equal, ?Greater)

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.

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, ?List1, ?List2)

As maplist/2, operating on pairs of elements from two lists.

maplist(:Goal, ?List1, ?List2, ?List3)

As maplist/2, operating on triples of elements from three lists.

maplist(:Goal, ?List1, ?List2, ?List3, ?List4)

As maplist/2, operating on quadruples of elements from four lists.

[det]convlist(:Goal, +ListIn, -ListOut)

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, 4.4, 2], L).
L = [9, 25, 4].

Compatibility

Also appears in YAP library(maplist) and SICStus library(lists).

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).

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, ..., Xm1, V0, V1),
      ...
      P(X1n, ..., Xmn, V', Vn).