[procedure] hashtable-update! table key update-fun init-value

Bigloo: If key is already in table, replaces its value with (update-fun value). Otherwise, the new entry with key and init-value is put into the table.

R6RS: Slighly differs when the entry doesn't already exist. In such case, (update-fun init-value) is evaluated and the result is put into the table with key.

See also make-hashtable, Concept:HashTable.

Other implementations have hash-table-update!, hash-table-update!/default.

 B and You