object IVisitor <object> .visit(UnOpNode node)
{
Node child = node.getLeft();
child.accept(this);
return(null);
}
private Node factor()
{
Node node = null;
switch (currentToken.type)
{
case "integer":
node = new IntNode(currentToken);
match(Token.INT);
break;
case "string":
node = new StrNode(currentToken);
match(Token.STRING);
break;
case "boolean":
node = new BoolNode(currentToken);
match(Token.BOOL);
break;
case "identifier":
node = new IdNode(currentToken);
match(Token.ID);
break;
case "lpar":
nextToken();
node = expr();
match(Token.RPAR);
break;
case "negation":
node = new UnOpNode(currentToken);
match(Token.NEG);
node.addChild(factor());
break;
default:
new SyntaxError(currentToken, "Syntax Error: Expected integer, string, bool, identifier or (, got " + currentToken.value);
break;
}
return(node);
}
object IVisitor <object> .visit(UnOpNode node)
{
switch (node.value)
{
case "!":
if (Convert.ToBoolean(evaluate(node.getLeft())))
{
return(0);
}
else
{
return(1);
}
default:
break;
}
return(null);
}
object IVisitor <object> .visit(UnOpNode node)
{
return(null);
}