This module extends the support for association lists in the SWI-Prolog standard library.

 merge_assoc(+New:assoc, +Old:assoc, -Merge:assoc) is det

Merges two association lists (New and Old) into one new association list (Merge).

If the same key appear in both New and Old, then the value from New is used and the value from Old is discarded.

 transpose_assoc(+Original:assoc, -Transposed:assoc) is det

Transposes an association list, i.e., turns all keys into values and all values into keys.

Re-exported predicates

The following predicates are re-exported from other modules

 empty_assoc(?Assoc) is semidet

Is true if Assoc is the empty association list.

 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. Does not validate that keys are sufficiently instantiated to ensure the tree remains valid if a key is further instantiated.

 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.

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

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

See also

- get_assoc/3.

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

True if Key-Value is an association in Assoc.

 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.

Errors

- domain_error(unique_key_pairs, List) if List contains duplicate keys

 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.

 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.

Errors

- domain_error(key_ordered_pairs, List) if pairs are not ordered.

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

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

 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.