Finite State Machines in Forth (1994)
Summary
This note presents methods to build deterministic and nondeterministic finite state machines in Forth, emphasizing table-driven state transitions over nested IFs. It covers brute-force FSMs, an elegant 4-wide FSM using a state table, and nondeterministic variants, with examples such as a numeric input parser and an identifier detector. The article discusses performance considerations and various implementation styles, including compile-time tables and run-time execution tokens.