Re: Overloaded Constructors?!?

[Michael Spencer]

[EMAIL PROTECTED] wrote:
 [trying to create a single Python class with the equivalent of the following 
overloaded constructors]
wxFoldWindowItem(wxWindow *wnd, int flags = wxFPB_ALIGN_WIDTH,
                 int ySpacing = wxFPB_DEFAULT_YSPACING,
                 int leftSpacing = wxFPB_DEFAULT_LEFTSPACING, 
                 int rightSpacing = wxFPB_DEFAULT_RIGHTSPACING)

or
wxFoldWindowItem(int y, const wxColour &lineColor = *wxBLACK, 
                 int ySpacing = wxFPB_DEFAULT_YSPACING,
                 int leftSpacing = wxFPB_DEFAULT_LEFTLINESPACING,
                 int rightSpacing = wxFPB_DEFAULT_RIGHTLINESPACING)

Several options in addition to the factory function that Kent has suggested (and 
 I'll assume he'll follow up with clarification)

# Option 1: one abstract base class holding all/most of the methods, and two 
separate subclasses reflecting the two use-cases.

class _AbstractFoldWindowItem(object):
    def __init__(self, *args, **kw):
        raise NotImplemetedError
    def
    ... all the shared methods
then
class FoldWindowItem(_AbstractFoldWindowItem):
    def __init__(self, wxWindow, flags = wxFPB_ALIGN_WIDTH,
                 ySpacing = wxFPB_DEFAULT_YSPACING,
                 leftSpacing = wxFPB_DEFAULT_LEFTSPACING,
                 rightSpacing = wxFPB_DEFAULT_RIGHTSPACING):
class FoldSeparator(_AbstractFoldWindowItem):
    def __init__(self, y, lineColor = wx.BLACK,
                 ySpacing = wx.FPB_DEFAULT_YSPACING,
                 leftSpacing = wx.FPB_DEFAULT_LEFTLINESPACING,
                 rightSpacing = wx.FPB_DEFAULT_RIGHTLINESPACING):
# Option 2: One class, two constructors:
class FoldWindowItem():
    def __init__(self, wxWindow, flags = wxFPB_ALIGN_WIDTH,
                 ySpacing = wxFPB_DEFAULT_YSPACING,
                 leftSpacing = wxFPB_DEFAULT_LEFTSPACING,
                 rightSpacing = wxFPB_DEFAULT_RIGHTSPACING):
        """Initializes with wxWindow"""
        self._type = wx.Window
    @classmethod
    def FromSeparator(cls, y, lineColor = wx.BLACK,
                 ySpacing = wx.FPB_DEFAULT_YSPACING,
                 leftSpacing = wx.FPB_DEFAULT_LEFTLINESPACING,
                 rightSpacing = wx.FPB_DEFAULT_RIGHTLINESPACING):
        newobj = cls.__new__(y, lineColor = wx.BLACK,
                 ySpacing = wx.FPB_DEFAULT_YSPACING,
                 leftSpacing = wx.FPB_DEFAULT_LEFTLINESPACING,
                 rightSpacing = wx.FPB_DEFAULT_RIGHTLINESPACING)
        newobj._type = wx.SEPARATOR
        # other initializatio
        return newobj
This requires the user code to call the class in two ways depending on how it is 
to be used:

i.e., myFoldWindowItem = FoldWindowItem(Window)
or myFoldWindowItem = FoldWindowItem.FromSeparator(y)

# Option 3: inspect the arguments and provide the signature details in the 
docstring
class FoldWindowItem():
    def __init__(self, obj, **kw):
        """Initialize with:
                 wxWindow, flags = wxFPB_ALIGN_WIDTH,
                 ySpacing = wxFPB_DEFAULT_YSPACING,
                 leftSpacing = wxFPB_DEFAULT_LEFTSPACING,
                 rightSpacing = wxFPB_DEFAULT_RIGHTSPACING)
            or:
                 y, lineColor = wx.BLACK,
                 ySpacing = wx.FPB_DEFAULT_YSPACING,
                 leftSpacing = wx.FPB_DEFAULT_LEFTLINESPACING,
                 rightSpacing = wx.FPB_DEFAULT_RIGHTLINESPACING)"""
        if isinstance(obj, wx.Window):
            # Do one thing
        elif isinstance(obj, wx.SEPARATOR):
            # Do the other
HTH
Michael
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