/// <summary>
/// Convert the presense / count of the enumerable expression(list/map) into bool true/false.
/// </summary>
/// <param name="expr">The list check expression.</param>
/// <returns></returns>
public object VisitListCheck(ListCheckExpr expr)
{
var varExp = expr.NameExp.Evaluate(this) as LObject;
if (varExp == LObjects.Null)
return new LBool(false);
var count = 0;
// 1. Array type ? check count
if (varExp.Type == LTypes.Array)
{
count = ((LArray)varExp).Value.Count;
}
// 2 Table Map type
else if (varExp.Type == LTypes.Map)
{
count = ((LMap)varExp).Value.Count;
}
// 3. Table type
else if (varExp.Type == LTypes.Table)
{
count = ((LTable) varExp).Value.Count;
}
// 3. Other type : keep count as 0 so we return false;
var result = count > 0 ? new LBool(true) : new LBool(false);
return result;
}
/// <summary>
/// Creates an expr that checks if the list variable supplied has any items.
/// </summary>
/// <param name="varName"></param>
/// <param name="token"></param>
/// <returns></returns>
public static Expr ListCheck(TokenData name, TokenData token)
{
var exp = new ListCheckExpr();
exp.NameExp = Ident(name.Token.Text, name);
SetupContext(exp, token);
return exp;
}
/// <summary>
/// Check the epxr which checks the presense / count of the enumerable expression(list/map) into bool true/false.
/// </summary>
/// <param name="expr">The list check expression.</param>
/// <returns></returns>
public object VisitListCheck(ListCheckExpr expr)
{
return null;
}