Migrate from Markdown to Djot
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Adrián Arroyo Calle
@@ -57,22 +57,22 @@
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/** Ordered set manipulation
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Ordered sets are lists with unique elements sorted to the standard order
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of terms (see sort/2). Exploiting ordering, many of the set operations
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of terms (see `sort/2`). Exploiting ordering, many of the set operations
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can be expressed in order N rather than N^2 when dealing with unordered
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sets that may contain duplicates. The library(ordsets) is available in a
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number of Prolog implementations. Our predicates are designed to be
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compatible with common practice in the Prolog community.
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Some of these predicates match directly to corresponding list
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operations. It is advised to use the versions from this library to make
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clear you are operating on ordered sets. An exception is member/2. See
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ord\_memberchk/2.
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clear you are operating on ordered sets. An exception is `member/2`. See
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`ord_memberchk/2`.
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The ordsets library is based on the standard order of terms. This
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implies it can handle all Prolog terms, including variables. Note
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however, that the ordering is not stable if a term inside the set is
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further instantiated. Also note that variable ordering changes if
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variables in the set are unified with each other or a variable in the
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set is unified with a variable that is `older' than the newest variable
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set is unified with a variable that is _older_ than the newest variable
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in the set. In practice, this implies that it is allowed to use
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member(X, OrdSet) on an ordered set that holds variables only if X is a
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fresh variable. In other cases one should cease using it as an ordset
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@@ -84,8 +84,8 @@ because the order it relies on may have been changed.
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% True if Term is an ordered set. All predicates in this library
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% expect ordered sets as input arguments. Failing to fullfil this
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% assumption results in undefined behaviour. Typically, ordered
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% sets are created by predicates from this library, sort/2 or
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% setof/3.
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% sets are created by predicates from this library, `sort/2` or
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% `setof/3`.
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is_ordset(Term) :-
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'$skip_max_list'(_, _, Term, Tail), Tail == [], %% is_list(Term),
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@@ -112,7 +112,7 @@ ord_empty([]).
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%% ord_seteq(+Set1, +Set2) is semidet.
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%
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% True if Set1 and Set2 have the same elements. As both are
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% canonical sorted lists, this is the same as ==/2.
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% canonical sorted lists, this is the same as `==/2`.
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ord_seteq(Set1, Set2) :-
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Set1 == Set2.
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@@ -148,7 +148,7 @@ ord_intersect__(>, H1, T1, _H2, T2) :-
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%% ord_disjoint(+Set1, +Set2) is semidet.
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%
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% True if Set1 and Set2 have no common elements. This is the
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% negation of ord\_intersect/2.
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% negation of `ord_intersect/2`.
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ord_disjoint(Set1, Set2) :-
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\+ ord_intersect(Set1, Set2).
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@@ -158,7 +158,7 @@ ord_disjoint(Set1, Set2) :-
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%
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% Intersection holds the common elements of Set1 and Set2.
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%
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% This predicate is **deprecated**. Use ord\_intersection/3
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% This predicate is *deprecated*. Use `ord_intersection/3`
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ord_intersect(Set1, Set2, Intersection) :-
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oset_int(Set1, Set2, Intersection).
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@@ -188,7 +188,7 @@ l_int([_-H|T], S0, S) :-
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%% ord_intersection(+Set1, +Set2, -Intersection) is det.
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%
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% Intersection holds the common elements of Set1 and Set2. Uses
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% ord\_disjoint/2 if Intersection is bound to `[]` on entry.
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% `ord_disjoint/2` if Intersection is bound to `[]` on entry.
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ord_intersection(Set1, Set2, Intersection) :-
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( Intersection == []
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@@ -201,7 +201,7 @@ ord_intersection(Set1, Set2, Intersection) :-
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%
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% Intersection and difference between two ordered sets.
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% Intersection is the intersection between Set1 and Set2, while
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% Difference is defined by ord\_subtract(Set2, Set1, Difference).
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% Difference is defined by `ord_subtract(Set2, Set1, Difference)`.
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ord_intersection([], L, [], L) :- !.
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ord_intersection([_|_], [], [], []) :- !.
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@@ -220,7 +220,7 @@ ord_intersection2(>, H1, T1, H2, T2, Intersection, [H2|HDiff]) :-
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%% ord_add_element(+Set1, +Element, ?Set2) is det.
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%
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% Insert an element into the set. This is the same as
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% ord\_union(Set1, [Element], Set2).
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% `ord_union(Set1, [Element], Set2)`.
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ord_add_element(Set1, Element, Set2) :-
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oset_addel(Set1, Element, Set2).
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@@ -229,7 +229,7 @@ ord_add_element(Set1, Element, Set2) :-
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%% ord_del_element(+Set, +Element, -NewSet) is det.
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%
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% Delete an element from an ordered set. This is the same as
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% ord\_subtract(Set, [Element], NewSet).
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% `ord_subtract(Set, [Element], NewSet)`.
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ord_del_element(Set, Element, NewSet) :-
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oset_delel(Set, Element, NewSet).
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@@ -237,13 +237,13 @@ ord_del_element(Set, Element, NewSet) :-
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%% ord_selectchk(+Item, ?Set1, ?Set2) is semidet.
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%
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% Selectchk/3, specialised for ordered sets. Is true when
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% `selectchk/3`, specialised for ordered sets. Is true when
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% select(Item, Set1, Set2) and Set1, Set2 are both sorted lists
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% without duplicates. This implementation is only expected to work
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% for Item ground and either Set1 or Set2 ground. The "chk" suffix
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% is meant to remind you of memberchk/2, which also expects its
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% first argument to be ground. ord\_selectchk(X, S, T) =>
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% ord\_memberchk(X, S) & \\+ ord\_memberchk(X, T).
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% is meant to remind you of `memberchk/2`, which also expects its
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% first argument to be ground. `ord_selectchk(X, S, T) =>
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% ord_memberchk(X, S) & \+ ord_memberchk(X, T).`
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%
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% Author: Richard O'Keefe
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@@ -263,13 +263,13 @@ ord_selectchk(Item, [Item|Set1], Set1) :-
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%
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% True if Element is a member of OrdSet, compared using ==. Note
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% that _enumerating_ elements of an ordered set can be done using
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% member/2.
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% `member/2`.
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%
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% Some Prolog implementations also provide ord\_member/2, with the
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% same semantics as ord\_memberchk/2. We believe that having a
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% semidet ord\_member/2 is unacceptably inconsistent with the \*\_chk
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% convention. Portable code should use ord\_memberchk/2 or
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% member/2.
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% Some Prolog implementations also provide `ord_member/2`, with the
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% same semantics as `ord_memberchk/2`. We believe that having a
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% semidet `ord_member/2` is unacceptably inconsistent with the \*\_chk
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% convention. Portable code should use `ord_memberchk/2` or
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% `member/2`.
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%
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% Author: Richard O'Keefe
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@@ -356,8 +356,8 @@ ord_union(Set1, Set2, Union) :-
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%% ord_union(+Set1, +Set2, -Union, -New) is det.
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%
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% True iff ord\_union(Set1, Set2, Union) and
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% ord\_subtract(Set2, Set1, New).
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% True iff `ord_union(Set1, Set2, Union)` and
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% `ord_subtract(Set2, Set1, New)`.
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ord_union([], Set2, Set2, Set2).
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ord_union([H|T], Set2, Union, New) :-
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@@ -389,14 +389,18 @@ ord_union_2([H|T], H2, T2, Union, New) :-
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% sequence below (but the actual implementation requires only a
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% single scan).
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%
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% ord_union(Set1, Set2, Union),
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% ord_intersection(Set1, Set2, Intersection),
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% ord_subtract(Union, Intersection, Difference).
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% ```
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% ord_union(Set1, Set2, Union),
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% ord_intersection(Set1, Set2, Intersection),
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% ord_subtract(Union, Intersection, Difference).
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% ```
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%
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% For example:
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% For example:
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%
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% ?- ord_symdiff([1,2], [2,3], X).
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% X = [1,3].
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% ```
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% ?- ord_symdiff([1,2], [2,3], X).
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% X = [1,3].
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% ```
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ord_symdiff([], Set2, Set2).
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ord_symdiff([H1|T1], Set2, Difference) :-
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