Here is the fully working code for everyone experiencing similar
bugs or problems with pointers and value types. =)
struct DeterministicState {
public:
this(string name, bool isFinal, DeterministicState *[char]
transits...) {
this.name = name;
this.finalState = isFinal;
this.addTransits(transits);
}
this(string name, bool isFinal) {
this.name = name;
this.finalState = isFinal;
}
this(bool isFinal, DeterministicState *[char] transits...) {
this("", isFinal, transits);
}
this(DeterministicState *[char] transits...) {
this("", false, transits);
}
void addTransits(DeterministicState *[char] newTransits) {
foreach (immutable key; newTransits.keys) {
transits[key] = newTransits[key];
}
}
string getName() const {
return name;
}
bool isFinalState() const {
return finalState;
}
bool hasNext(char input) const {
return (input in transits) ? true : false;
}
DeterministicState * getNext(char input) {
return transits[input];
}
string toString() const {
return name;
}
private:
string name;
DeterministicState *[char] transits;
bool finalState;
}
struct DeterministicFiniteAutomaton {
public:
DeterministicState *[] input(char[] input) {
DeterministicState *[] trace = [ start ];
auto currentState = trace[0];
foreach (immutable c; input) {
if (!currentState.hasNext(c)) {
writeln(currentState.toString() ~ " has no next for " ~
to!string(c));
break;
} else {
writeln(currentState.toString() ~ " has next for " ~
to!string(c));
}
currentState = currentState.getNext(c);
trace ~= currentState;
}
return trace;
}
this(DeterministicState * start) {
this.start = start;
}
private:
DeterministicState * start;
}
void main()
{
auto s0 = DeterministicState("s0", false);
auto s1 = DeterministicState("s1", false);
auto s2 = DeterministicState("s2", true);
s0.addTransits(['0' : & s1, '1' : & s2]);
s1.addTransits(['0' : & s0, '1' : & s2]);
s2.addTransits(['0' : & s2, '1' : & s2]);
auto dfa = DeterministicFiniteAutomaton(& s0);
auto trace = dfa.input("0001".dup);
foreach (t; trace) {
writeln(t.toString());
}
writeln("Trace Length = " ~ to!string(trace.length));
}
Regards,
Rob