SWI-Prolog -- library(assoc)

assoc_to_list/2	Translate assoc into a pairs list
assoc_to_keys/2	Translate assoc into a key list
assoc_to_values/2	Translate assoc into a value list
empty_assoc/1	Test/create an empty assoc
gen_assoc/3	Non-deterministic enumeration of assoc
get_assoc/3	Get associated value
get_assoc/5	Get and replace associated value
list_to_assoc/2	Translate pair list to assoc
map_assoc/2	Test assoc values
map_assoc/3	Map assoc values
max_assoc/3	Max key-value of an assoc
min_assoc/3	Min key-value of an assoc
ord_list_to_assoc/2	Translate ordered list into an assoc
put_assoc/4	Add association to an assoc