An automaton, is a logical machine that models the process of computation.

Types of Automata

Turing machine
Finite state machine
Deterministic finite state machine
Pushdown automaton
. . .


An automaton can also be used as a powerful control structure, transcending the block-hierarchical paradigm of structured programming. The following pages are related:

A tiny state machine
Finite state machines
Automata in Tcl
Goto in Tcl

The need for such power is most often felt when parsing or doing IPC.

AM 2010-07-19: Quite apart from the above, automata are also studied as mathematical objects - see the book A New kind of Science , by Stephen Wolfram, for instance. A simple program with complex behaviour is one example.