Automatas in Scala

DFA1.scala

class DFA[StateType]
(
    val Q:Set[StateType],
    val F:Set[StateType],
    val q0:StateType, 
    val delta: (StateType,Char)=>StateType,
    val Sigma:Set[Char]
)
{
    ...

dfa_accepts.scala

def accepts(input:List[Char]):Boolean =F contains deltaHat(q0,input) 

dfa_delta.scala

    // sample DFA transition function
    def dfa1_delta(state:Int,inp:Char)={
        state match {
            case 0=>
                if(inp=='a') 0 else 1;
            case 1=>
                if(inp=='a') 2 else 1;
            case 2=> 2
        }
    }

dfa_delta_hat.scala

def deltaHat(state:StateType,input:List[Char]):StateType= {
    input match {
        case Nil => state;
        case head::tail => deltaHat(delta(state,head),tail)
    }
}

dfa_use.scala

val Q=Set(0,1,2);
val F=Set(2);
val d=new DFA(Q,F,0,dfa1_delta,Set('a','b'));
println(d.accepts(List('b','a')));