Scryer Prolog documentation

Module assoc

:- use_module(library(assoc)).

Binary associations

Assocs are Key-Value associations implemented as a balanced binary tree (AVL tree).

Authors: R.A.O'Keefe, L.Damas, V.S.Costa and Jan Wielemaker

empty_assoc(?Assoc) is semidet.

Is true if Assoc is the empty association list.

assoc_to_list(+Assoc, -Pairs) is det.

Translate Assoc to a list Pairs of Key-Value pairs. The keys in Pairs are sorted in ascending order.

assoc_to_keys(+Assoc, -Keys) is det.

True if Keys is the list of keys in Assoc. The keys are sorted in ascending order.

assoc_to_values(+Assoc, -Values) is det.

True if Values is the list of values in Assoc. Values are ordered in ascending order of the key to which they were associated. Values may contain duplicates.

is_assoc(+Assoc) is semidet.

True if Assoc is an association list. This predicate checks that the structure is valid, elements are in order, and tree is balanced to the extent guaranteed by AVL trees. I.e., branches of each subtree differ in depth by at most 1.

gen_assoc(?Key, +Assoc, ?Value) is nondet.

True if Key-Value is an association in Assoc. Enumerates keys in ascending order on backtracking.

get_assoc(+Key, +Assoc, -Value) is semidet.

True if Key-Value is an association in Assoc.

Throws error: type_error(assoc, Assoc) if Assoc is not an association list.

get_assoc(+Key, +Assoc0, ?Val0, ?Assoc, ?Val) is semidet.

True if Key-Val0 is in Assoc0 and Key-Val is in Assoc.

list_to_assoc(+Pairs, -Assoc) is det.

Create an association from a list Pairs of Key-Value pairs. List must not contain duplicate keys.

Throws error: domain_error(unique_key_pairs, List) if List contains duplicate keys

ord_list_to_assoc(+Pairs, -Assoc) is det.

Assoc is created from an ordered list Pairs of Key-Value pairs. The pairs must occur in strictly ascending order of their keys.

Throws error: domain_error(key_ordered_pairs, List) if pairs are not ordered.

ord_pairs(+Pairs) is semidet

True if Pairs is a list of Key-Val pairs strictly ordered by key.

map_assoc(:Pred, +Assoc) is semidet.

True if Pred(Value) is true for all values in Assoc.

map_assoc(:Pred, +Assoc0, ?Assoc) is semidet.

Map corresponding values. True if Assoc is Assoc0 with Pred applied to all corresponding pairs of of values.

max_assoc(+Assoc, -Key, -Value) is semidet.

True if Key-Value is in Assoc and Key is the largest key.

min_assoc(+Assoc, -Key, -Value) is semidet.

True if Key-Value is in assoc and Key is the smallest key.

put_assoc(+Key, +Assoc0, +Value, -Assoc) is det.

Assoc is Assoc0, except that Key is associated with Value. This can be used to insert and change associations.

del_min_assoc(+Assoc0, ?Key, ?Val, -Assoc) is semidet.

True if Key-Value is in Assoc0 and Key is the smallest key. Assoc is Assoc0 with Key-Value removed. Warning: This will succeed with no bindings for Key or Val if Assoc0 is empty.

del_max_assoc(+Assoc0, ?Key, ?Val, -Assoc) is semidet.

True if Key-Value is in Assoc0 and Key is the greatest key. Assoc is Assoc0 with Key-Value removed. Warning: This will succeed with no bindings for Key or Val if Assoc0 is empty.

del_assoc(+Key, +Assoc0, ?Value, -Assoc) is semidet.

True if Key-Value is in Assoc0. Assoc is Assoc0 with Key-Value removed.

max_assoc/3