`make_hash`

computes the needed data to turn the DFA `a`

into a hashing
automaton. A hashing automaton provides a highly efficient way to
implement a bidirectionnal mapping (known as perfect hash function)
between strings of any character type and the positive integers. Such
an automaton can be used with the algorithms `hash_value`

and
`value_hash`

.
Vincent Le Maout 2003-07-08