First commit

nfa.go

@@ -0,0 +1,38 @@
+package main
+
+const EPSILON int = 0
+
+type State struct {
+	content     int            // Contents of current state
+	isEmpty     bool           // If it is empty - Union operator states will be empty
+	isLast      bool           // If it is the last state (acept state)
+	output      []*State       // The outputs of the current state ie. the 'outward arrows'. A union operator state will have more than one of these.
+	transitions map[int]*State // Transitions to different states (can be associated with an int, representing content of destination state)
+}
+
+type NFA struct {
+	start   State
+	outputs []State
+}
+
+// verifyLastStatesHelper performs the depth-first recursion needed for verifyLastStates
+func verifyLastStatesHelper(state *State, visited map[*State]bool) {
+	if len(state.transitions) == 0 {
+		state.isLast = true
+		return
+	}
+	if visited[state] == true {
+		return
+	}
+	visited[state] = true
+	for k := range state.transitions {
+		if state.transitions[k] != state {
+			verifyLastStatesHelper(state.transitions[k], visited)
+		}
+	}
+}
+
+// verifyLastStates penables the 'isLast' flag for the leaf nodes (last states)
+func verifyLastStates(start []State) {
+	verifyLastStatesHelper(&start[0], make(map[*State]bool))
+}