public static String parse(
Lexer lexer,
HashMap<Nonterminal, HashMap<Terminal, Rule>> parsingTable,
Nonterminal startSymbol) {
Stack<Token> stack = new Stack<Token>();
ArrayList<Terminal> inputs = lexer.getTokens();
int count = 0;
stack.push(startSymbol);
while (!stack.isEmpty() && count < inputs.size()) {
Token top = stack.peek();
System.out.println(
"Testing top: " + top.toString() + ", next input: " + inputs.get(count).toString());
if (top instanceof Nonterminal) {
Nonterminal nextNonTerm = (Nonterminal) top;
Rule rules = parsingTable.get(nextNonTerm).get(inputs.get(count));
if (rules == null)
return "Invalid. No rule found for "
+ nextNonTerm.toString()
+ " and the input "
+ inputs.get(count);
stack.pop();
for (int i = rules.rule.length - 1; i > -1; i--) {
if (!rules.rule[i].equals(new Terminal(Terminal.TerminalType.EPSILON)))
stack.push(rules.rule[i]);
}
} else if (top instanceof Terminal) {
Terminal nextTerm = (Terminal) top;
Terminal nextInput = inputs.get(count);
if (nextTerm.equals(nextInput)) {
++count;
stack.pop();
} else return nextTerm + " and " + nextInput + " do not match: invalid";
}
System.out.println("Current stack: " + stack.toString());
}
if (stack.isEmpty()) return "Valid";
return "Invalid. Ran out of tokens early or ran over input count";
}
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
Vuelo other = (Vuelo) obj;
if (avion == null) {
if (other.avion != null) return false;
} else if (!avion.equals(other.avion)) return false;
if (id != other.id) return false;
if (pista == null) {
if (other.pista != null) return false;
} else if (!pista.equals(other.pista)) return false;
if (terminal == null) {
if (other.terminal != null) return false;
} else if (!terminal.equals(other.terminal)) return false;
return true;
}
