Utility operations built up from the Associative mapping protocol:

delete-at* ( key assoc -- value/f ? )

rename-at ( newkey key assoc -- )

change-at ( ..a key assoc quot: ( ..a value -- ..b newvalue ) -- ..b )

at+ ( n key assoc -- )

inc-at ( key assoc -- )

See also
set-at, delete-at, clear-assoc, push-at