# DFA

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A DFA, also known as a Deterministic Finite Automata or "deterministic finite state machine" is a finite state machine capable of recognizing regular languages (languages recognizable using regular expressions). It can recognize repeated but not recursive structures.

DFAs are called "deterministic" because for each state and input symbol there is one and only one transition to the next state.

### Software that uses DFAs

- ANTLR constructs DFAs for the purposes of predicting alternatives.
- Ragel is a state machine compiler.