/// <summary>
/// Attempts to invoke a meta-method and returns the result.
/// </summary>
/// <param name="type">The type of operation.</param>
/// <param name="other">The other value.</param>
/// <returns>The result of the meta-method, or null if not found.</returns>
internal static ILuaValue AttempMetamethod(BinaryOperationType type, ILuaValue self, ILuaValue other)
{
if (type == BinaryOperationType.And || type == BinaryOperationType.Or)
{
return(null);
}
// Search the first object.
ILuaValue ret = null;
var self2 = self as ILuaTable;
if (self2 != null && self2.MetaTable != null)
{
var t = self2.MetaTable.GetItemRaw(LuaString._metamethods[type]);
if (t != null)
{
ret = t.Invoke(LuaNil.Nil, false, -1, new LuaMultiValue(self, other));
}
else if (type == BinaryOperationType.Lte || type == BinaryOperationType.Gt)
{
t = self2.MetaTable.GetItemRaw(LuaString._metamethods[BinaryOperationType.Lt]);
if (t != null)
{
ret = t.Invoke(LuaNil.Nil, false, -1, new LuaMultiValue(other, self)).Not();
}
}
}
// Search the second object.
var other2 = other as ILuaTable;
if (ret == null && other2 != null && other2.MetaTable != null)
{
var t = other2.MetaTable.GetItemRaw(LuaString._metamethods[type]);
if (t != null)
{
ret = t.Invoke(LuaNil.Nil, true, -1, new LuaMultiValue(self, other));
}
else if (type == BinaryOperationType.Lte || type == BinaryOperationType.Gt)
{
t = other2.MetaTable.GetItemRaw(LuaString._metamethods[BinaryOperationType.Lt]);
if (t != null)
{
ret = t.Invoke(LuaNil.Nil, true, -1, new LuaMultiValue(other, self)).Not();
}
}
}
// Fix the arguments for comparisons.
if (ret != null)
{
ret = ret.Single();
switch (type)
{
case BinaryOperationType.Gt:
case BinaryOperationType.Gte:
case BinaryOperationType.NotEquals:
ret = LuaBoolean.Create(!ret.IsTrue);
break;
case BinaryOperationType.Equals:
case BinaryOperationType.Lt:
case BinaryOperationType.Lte:
ret = LuaBoolean.Create(ret.IsTrue);
break;
}
}
return(ret);
}