Add memory management operators (AddRef & Finalize)

[ollydev]

Added class operators AddRef and Finalize. The user must implement their own refcounting if needed:

type
  TManagedRecord = record
    MyObject: Int32;
    Ref: ^Int32;
  end;

class operator TManagedRecord.AddRef(var Obj: TManagedRecord);
begin
  Assert(Obj.Ref <> nil);

  Obj.Ref^ += 1;
end;

class operator TManagedRecord.Finalize(var Obj: TManagedRecord);
var
  i: Int32;
begin
  Assert(Obj.Ref <> nil);
  Assert(Obj.Ref^ > 0);

  Dec(Obj.Ref^);
  if (Obj.Ref^ > 0) then
    Exit;

  // Free stuff here!

  FreeMem(Obj.Ref);
end;

function GetManagedRecord: TManagedRecord;
begin
  Result.MyObject := 123;
  Result.Ref := GetMem(SizeOf(Int32));
  Result.Ref^ := 1;
end;

Perhaps in the future an magic record can be added to inherit from which would do the refcounting internally?

---

Most of the work is on in TLapeTree_Operator.Compile when assigning:

• If Left is writable: Call Finalize
• If Right isn't a constant: Call AddRef
• After assignment if Right is an TLapeTree_Invoke result call VarToDefault to prevent double finalizing when the function cleans up.

Other changes:

• Replaced Eval(op_Assign) calls with TLapeTree_Operator.Create(op_Assign) so these management operators are considered.
• Skip writable check in TLapeTree_Operator only if Left.VarPos.MemPos=mpStack. Assume the stack has been correctly grown if Left is constant and so on.
• Check PType in TLapeType_Pointer.Equals
• Remove full disposal mode, The finalize operator can be used to replace this.
• Removed operator method parsing from ParseMethod by adding ParseOperatorMethod. lpcompiler.pas diff is large due to mostly changing the indent of ParseMethod.
• _Dispose is now generated if type has finalize/addref operator and calls finalize operator.
• _Assign is now generated if type has finalize/addref operator.

[slackydev]

Cool

[ollydev]

Will be reworked.