private static INfa Any()
{
var start = new NfaState();
var end = new NfaState();
start.AddTransistion(new TerminalNfaTransition(new AnyTerminal(), end));
return new Nfa(start, end);
}
private static INfa Character(RegexCharacter character)
{
var start = new NfaState();
var end = new NfaState();
var terminal = new CharacterTerminal(character.Value);
var transition = new TerminalNfaTransition(
terminal: terminal,
target: end);
start.AddTransistion(transition);
return new Nfa(start, end);
}
private static INfa Character(RegexCharacterClassCharacter character, bool negate)
{
var start = new NfaState();
var end = new NfaState();
ITerminal terminal = new CharacterTerminal(character.Value);
if (negate)
terminal = new NegationTerminal(terminal);
var transition = new TerminalNfaTransition(
terminal: terminal,
target: end);
start.AddTransistion(transition);
return new Nfa(start, end);
}
private static INfa Empty()
{
var start = new NfaState();
var end = new NfaState();
start.AddTransistion(new NullNfaTransition(end));
return new Nfa(start, end);
}
private static INfa Union(INfa first, INfa second)
{
var start = new NfaState();
start.AddTransistion(new NullNfaTransition(first.Start));
start.AddTransistion(new NullNfaTransition(second.Start));
var end = new NfaState();
var endTransition = new NullNfaTransition(end);
first.End.AddTransistion(endTransition);
second.End.AddTransistion(endTransition);
return new Nfa(start, end);
}
private static INfa Range(RegexCharacterRange range, bool negate)
{
// combine characters into a character range terminal
var start = range.StartCharacter.Value;
var end = range.EndCharacter.Value;
ITerminal terminal = new RangeTerminal(start, end);
var nfaStartState = new NfaState();
var nfaEndState = new NfaState();
if (negate)
terminal = new NegationTerminal(terminal);
nfaStartState.AddTransistion(
new TerminalNfaTransition(terminal, nfaEndState));
return new Nfa(nfaStartState, nfaEndState);
}
private static INfa Optional(INfa nfa)
{
var start = new NfaState();
var end = new NfaState();
start.AddTransistion(new NullNfaTransition(nfa.Start));
start.AddTransistion(new NullNfaTransition(end));
nfa.End.AddTransistion(new NullNfaTransition(end));
return new Nfa(start, end);
}
private static INfa KleeneStar(INfa nfa)
{
var start = new NfaState();
var nullToNfaStart = new NullNfaTransition(nfa.Start);
start.AddTransistion(nullToNfaStart);
nfa.End.AddTransistion(nullToNfaStart);
var end = new NfaState();
var nullToNewEnd = new NullNfaTransition(end);
start.AddTransistion(nullToNewEnd);
nfa.End.AddTransistion(nullToNewEnd);
return new Nfa(start, end);
}
