empty an empty map.

singleton k v returns a map with a single key k and value v pair.

size m returns the number of elements of the map m in constant time.

find ctxt k m looks up the value with key k in the given map m and also consumes the gas associated with the lookup. The complexity is logarithmic in the size of the map.

update ctxt k f map updates or adds the value of the key k using f. The function accounts for the gas cost for finding the element. The updating function f should also account for its own gas cost. The complexity is logarithmic in the size of the map.

to_list m transforms a map m into a list. It also accounts for the gas cost for traversing the elements. The complexity is linear in the size of the map.

of_list ctxt ~merge_overlaps m creates a map from a list of key-value pairs. In case there are overlapping keys, their values are combined using the merge_overlap function. The function accounts for gas for traversing the elements. merge_overlap should account for its own gas cost. The complexity is n * log n in the size of the list.

merge ctxt ~merge_overlap m1 m2 merges the maps m1 and m2. In case there are overlapping keys, their values are combined using the merge_overlap function. Gas costs for traversing all elements from both maps are accounted for. merge_overlap should account for its own gas cost. The complexity is n * log n, where n is size m1 + size m2.

map ctxt f m maps over all key-value pairs in the map m using the function f. It accounts for gas costs associated with traversing the elements. The mapping function f should also account for its own gas cost. The complexity is linear in the size of the map m.

fold ctxt f z m folds over the key-value pairs of the given map m, accumulating values using f, with z as the initial state. The function f must account for its own gas cost. The complexity is linear in the size of the map m.