Order in metaclass

[Peter Otten]

Bengt Richter wrote:

> Or, an ugly hack that might work for a while, depending on how
> co_names is really generated. It seems in order of occurrence
> (including right hand sides of assignment, but still top down) ...
> 
> >>> import sys
> >>> def getnames(): return sys._getframe(1).f_code.co_names
> ...
> >>> def MC(cname, cbases, cdict):
> ...     names = cdict.get('ordic',[])
> ...     names = [name for name in names if name in cdict]
> ...     cdict['ordic'] = dict([(name,i) for i,name in enumerate(names)])
> ...     return type(cname, cbases, cdict)
> ...
> >>> class C(object):
> ...     __metaclass__ = MC # really a function shortcut
> ...     x = 123
> ...     y = sys
> ...     z = 0
> ...     ordic = getnames()
> ...
> >>> C.ordic
> {'ordic': 5, '__module__': 0, '__metaclass__': 1, 'y': 3, 'x': 2, 'z': 4}

A metaclass /function/ and sys._getframe() exercised on a class definition
- I think you have raised the bar for what qualifies as a hack :-)

Peter