/// <summary>
/// Gets a see MemberAccess object that represents the instance, member name and other information on the member access expression.
/// </summary>
/// <param name="node">The Ast node associated with the member access operation</param>
/// <param name="methods">The collection of registered methods on various types</param>
/// <param name="obj">The object on which the member access is being performed.</param>
/// <param name="memberName">The name of the member to get.</param>
/// <returns></returns>
public static MemberAccess GetLangBasicTypeMember(AstNode node, RegisteredMethods methods, LObject obj, string memberName)
{
var type = obj.Type;
// Get the methods implementation LTypeMethods for this basic type
// e.g. string, date, time, array , map
// e.g. LStringType LDateType, LTimeType, LArrayType, LMapType
var typeMethods = methods.Get(type);
var memberExists = typeMethods.HasMember(obj, memberName);
// 1. Can set non-existing map properties
if (type == LTypes.Map && !memberExists)
{
var nonExistMAccess = new MemberAccess(MemberMode.PropertyMember);
nonExistMAccess.Name = type.Name;
nonExistMAccess.Instance = obj;
nonExistMAccess.MemberName = memberName;
nonExistMAccess.Type = type;
nonExistMAccess.MemberMissing = true;
return nonExistMAccess;
}
// 2. Check that the member exists.
if (!memberExists)
throw ExceptionHelper.BuildRunTimeException(node, "Property or Member : " + memberName + " does not exist");
// 3. It's either a Property or method
var isProp = typeMethods.HasProperty(obj, memberName);
var mode = isProp ? MemberMode.PropertyMember : MemberMode.MethodMember;
var maccess = new MemberAccess(mode);
maccess.Name = type.Name;
maccess.Instance = obj;
maccess.MemberName = memberName;
maccess.Type = type;
return maccess;
}
/// <summary>
/// Evaluate the result of indexing an object e.g. users[0] or users["admins"]
/// </summary>
/// <param name="regmethods"></param>
/// <param name="node"></param>
/// <param name="target"></param>
/// <param name="ndxObj"></param>
/// <returns></returns>
public static LObject AccessIndex(RegisteredMethods regmethods, AstNode node, LObject target, LObject ndxObj)
{
object result = LObjects.Null;
// Case 1: Array access users[0];
if (target.Type == LTypes.Array || target.Type.TypeVal == LTypes.Table.TypeVal)
{
var ndx = ((LNumber)ndxObj).Value;
var isArray = target.Type == LTypes.Array;
var methods = isArray ? regmethods.Get(LTypes.Array) : regmethods.Get(LTypes.Table);
// TODO: Make this generic.
var length = Convert.ToInt32(methods.ExecuteMethod(target, "length", null));
if(ndx >= length)
throw ExceptionHelper.BuildRunTimeException(node, "Index out of bounds : '" + ndx + "'");
result = methods.GetByNumericIndex(target, (int)ndx);
}
// Case 2: Map access. users["kishore"];
else if (target.Type == LTypes.Map)
{
var memberName = ((LString)ndxObj).Value;
var methods = regmethods.Get(LTypes.Map);
if (!methods.HasProperty(target, memberName))
throw ExceptionHelper.BuildRunTimeException(node, "Property does not exist : '" + memberName + "'");
result = methods.GetByStringMember(target, memberName);
}
// Conver to lang type.
if(result != LObjects.Null && !(result is LObject))
{
result = LangTypeHelper.ConvertToLangValue(result);
}
return (LObject)result;
}
