Another huge game changer feature: Delegate function pointer types (Call by pointer)

[fafalone]

Thought this feature was also worth flagging for those who don't follow tB GitHub or Discord.

twinBASIC now supports Call By Pointer, by way of Delegates, which are function pointer types.

    Private Delegate Function Delegate1 (ByVal A As Long, ByVal B As Long) As Long
    
    Private Sub Command1_Click()
        Dim myDelegate As Delegate1 = AddressOf Addition
        MsgBox "Answer: " & myDelegate(5, 6)
    End Sub
    
    Public Function Addition(ByVal A As Long, ByVal B As Long) As Long
        Return A + B
    End Function

You can of course also use a LongPtr variable to assign to the delegate type.

The delegate type can also be used in interface/API declarations and as members of a User-defined type, for example, the ChooseColor API:

Public Delegate Function CCHookProc (ByVal hwnd As LongPtr, ByVal uMsg As Long, ByVal wParam As LongPtr, ByVal lParam As LongPtr) As LongPtr
Public Type CHOOSECOLOR
    lStructSize As Long
    hwndOwner As LongPtr
    hInstance As LongPtr
    rgbResult As Long
    lpCustColors As LongPtr
    Flags As ChooseColorFlags
    lCustData As LongPtr
    lpfnHook As CCHookProc 'Delegate function pointer type instead of LongPtr
    lpTemplateName As LongPtr
End Type

If you already have code assigning a Long/LongPtr to the lpfnHook member, it will continue to work normally, but now you can also have the type safety benefits of setting it to a method matching the Delegate:

Dim tCC As CHOOSECOLOR
tCC.lpfnHook = AddressOf ChooseColorHookProc

...

Public Function ChooseColorHookProc(ByVal hwnd As LongPtr, ByVal uMsg As Long, ByVal wParam As LongPtr, ByVal lParam As LongPtr) As LongPtr

End Function

A much, much better way of implementing call by pointer compared to the standard ways of DispCallFunc or asm thunks!