HELP KEY_OF_DATAWORD                     updated Mark Rubinstein  October 1985

    key_of_dataword(word) -> key

Given the dataword of a class, this returns the corresponding key.  E.g. if
the word is "integer" this will return the key for the class integers.

See HELP * CLASSES, *DATAWORD, *DATAKEY
See also REF * KEYS for full details.