https://github.com/dbrgn/ndfa

Nondeterministic and deterministic finite automata
https://github.com/dbrgn/ndfa

Last synced: 10 months ago
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Nondeterministic and deterministic finite automata

• Host: GitHub
• URL: https://github.com/dbrgn/ndfa
• Owner: dbrgn
• License: other
• Created: 2012-07-28T14:08:05.000Z (almost 14 years ago)
• Default Branch: master
• Last Pushed: 2012-07-28T14:15:14.000Z (almost 14 years ago)
• Last Synced: 2025-09-01T15:52:05.010Z (10 months ago)
• Language: Python
• Size: 105 KB
• Stars: 3
• Watchers: 4
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

          
ndfa - nondeterministic and deterministic finite automata

=========================================================

Finit state machine implementations.

`ndfa.py` currently contains only a DFA class. NFA will follow later.

Usage

-----

Here is an example of a DFA that accepts strings with an even number of 'a's.

    from ndfa import DFA

    states = list('01')

    alphabet = list('ab')

    transitions = {

        ('0', 'a'): '1',

        ('0', 'b'): '0',

        ('1', 'a'): '0',

        ('1', 'b'): '1',

    }

    start = '0'

    accepts = list('0')

    dfa = DFA(states, alphabet, transitions, start, accepts)

To test some words with this dfa:

    >>> dfa.test('')

    True

    >>> dfa.test('aababa')

    True

    >>> dfa.test('baaa')

    False

    >>> dfa.test('foo')

    Traceback (most recent call last):

      File "", line 1, in 

      File "ndfa.py", line 24, in test

        'Symbol "%s" must be in alphabet.' % symbol

    AssertionError: Symbol "f" must be in alphabet.

Output

------

The DFA class uses the python logging module. To see basic output, set log

level to INFO:

    >>> import logging

    >>> logging.basicConfig(level=logging.INFO, format='%(message)s')

    >>> dfa.test('aba')

    Testing word "aba"...

    Accepted: True

...or to DEBUG for more verbose output:

    >>> import logging

    >>> logging.basicConfig(level=logging.DEBUG, format='%(message)s')

    >>> dfa.test('aba')

    Testing word "aba"...

    Initial state: 0

    Current symbol: a

    New state: 1

    Current symbol: b

    New state: 1

    Current symbol: a

    New state: 0

    Final state: 0

    Accepted: True

License

-------

GPLv3, see LICENSE.md