private Expr And()
{
Expr expr = Equality();
while (Match(TokenType.AND))
{
Token op = Previous();
Expr right = Equality();
expr = new Logical(expr, op, right);
}
return(expr);
}
private Expr Or()
{
Expr expr = And();
while (Match(TokenType.OR))
{
Token op = Previous();
Expr right = And();
expr = new Logical(expr, op, right);
}
return(expr);
}
public object VisitLogicalExpr(Logical expr)
{
Object left = Evaluate(expr.left);
if (expr.op.type == TokenType.OR)
{
if (IsTruthy(left))
{
return(left);
}
}
else
{
if (!IsTruthy(left))
{
return(left);
}
}
return(Evaluate(expr.right));
}
public string VisitLogicalExpr(Logical expr)
{
return(Parenthesize(expr.op.lexeme, expr.left, expr.right));
}
public object VisitLogicalExpr(Logical expr)
{
Resolve(expr.left);
Resolve(expr.right);
return(null);
}