private Expression And()
{
var expression = Equality();
while (Match(TokenType.And))
{
var token = Previous();
var right = Equality();
expression = new Expression.Logical(expression, token, right);
}
return(expression);
}
private Expression Or()
{
var expression = And();
while (Match(TokenType.Or))
{
var token = Previous();
var right = And();
expression = new Expression.Logical(expression, token, right);
}
return(expression);
}
public object VisitLogical(Expression.Logical expression)
{
var left = Evaluate(expression.Left);
if (expression.Operator.Type == TokenType.Or)
{
if (IsTruthy(left))
{
return(left);
}
}
else
{
if (!IsTruthy(left))
{
return(left);
}
}
return(Evaluate(expression.Right));
}
public string VisitLogical(Expression.Logical expression)
{
return(Parenthesize(expression.Left.Accept(this) + expression.Operator.Lexeme + expression.Right.Accept(this)));
}