Automata

A library for simulating deterministic finite Automata in Haskell

Usage:

-- Example: automata that determines if a binary number is divisible by 4
import Automata
-- the initial state
init = 1
-- a list of end states
endstates = [3]
-- a function state -> string -> state to simulate a transition table
delta i s
        | i == 1 && s == "1" = 1
        | i == 1 && s == "0" = 2
        | i == 2 && s == "1" = 1
        | i == 2 && s == "0" = 3
        | i == 3 && s == "1" = 1
        | i == 3 && s == "0" = 3
        --- 0 als failure state
        | otherwise = 0


a = (endstates,init,delta)

-- check if 4 is in the language (is divisible by 4)
checkword a ["1","0","0"]


-- Example 2: automata that checks if a word is a vector

endstates = [5]
s = 1

delta i s
        | i == 1 && s == "(" = 2
        | i == 2 && s == "-" = 3
        | i == 2 && s `element` ["0","1","2","3","4","5","6","7","8","9"] = 4
        | i == 3 && s `element` ["0","1","2","3","4","5","6","7","8","9"] = 4
        | i == 4 && s == ";" = 2
        | i == 4 && s `element` ["0","1","2","3","4","5","6","7","8","9"] = 4
        | i == 4 && s == ")" = 5
        --- 0 as failure state
        | otherwise = 0
       
a = (endstates,s,delta)

--check if  (0;0;0) is valid notation for a vector
checkword a ["(","0",";","0",";","0",")"]