4 ms·

I'd rather utilize a metaclass in this special case. This would retain the notion of Foo being a type much better than transmogrifying a function into a class.

I'd rather utilize a metaclass in this special case. This would retain the notion of Foo being a type much better than transmogrifying a function into a class. (Granted, there's not that big a difference technically but you're tricking other programmers into believing Foo cannot be used for eg. isinstance.) class Foo(Struct): __endian__ = Struct.LE foo = Struct.uint32 bar = Struct.string(foo) If you don't like specifying the endianness as a class attribute you could still inherit from Struct.LE/BE rather than Struct itself. Quick technical howto: make Struct have a __metaclass__ class attribute, populate the __metaclass__ class with a __new__ or __init__ method performing the desired transformations. See http://www.python.org/download/releases/2.2/descrintro/#metaclasses http://www.python.org/download/releases/2.2/descrintro/#meta... for details on metaclasses.

daeken 17y ago
Metaclasses won't fly in this case, since the order of struct members has to be kept. Tried a bunch of things to make it work, but in the end nothing came out cleaner.
- jbox 17y ago
  "Metaclasses won't fly in this case, since the order of struct members has to be kept." Couldn't you use a creation counter in a metaclasses and assign order to the attributes as they are added? (like Django's forms use to keep track of field order)
  - daeken 17y ago
    Huh, I hadn't thought about that... I may be able to pull that off. Thanks for the suggestion.
  - lehmannro 17y ago
    Oh, I didn't think about the order. Django's approach to this issue is really simple and only requires that all your Struct fields are instances of some common base class. http://code.djangoproject.com/browser/django/trunk/django/forms/fields.py#L97 http://code.djangoproject.com/browser/django/trunk/django/fo... creation of the counter on individual fields http://code.djangoproject.com/browser/django/trunk/django/forms/forms.py#L37 http://code.djangoproject.com/browser/django/trunk/django/fo... application of the counter upon field harvesting

daeken 17y ago

Metaclasses won't fly in this case, since the order of struct members has to be kept. Tried a bunch of things to make it work, but in the end nothing came out cleaner.

jbox 17y ago
"Metaclasses won't fly in this case, since the order of struct members has to be kept." Couldn't you use a creation counter in a metaclasses and assign order to the attributes as they are added? (like Django's forms use to keep track of field order)
- daeken 17y ago
  Huh, I hadn't thought about that... I may be able to pull that off. Thanks for the suggestion.
- lehmannro 17y ago
  Oh, I didn't think about the order. Django's approach to this issue is really simple and only requires that all your Struct fields are instances of some common base class. http://code.djangoproject.com/browser/django/trunk/django/forms/fields.py#L97 http://code.djangoproject.com/browser/django/trunk/django/fo... creation of the counter on individual fields http://code.djangoproject.com/browser/django/trunk/django/forms/forms.py#L37 http://code.djangoproject.com/browser/django/trunk/django/fo... application of the counter upon field harvesting