David Driver wrote:
> What I would like to do is something like this:
>
> class testObj(object):
> _rules = list()
> def evalRules(self):
> for r in _rules:
> r()
> def rule(func):
> if not func in func.__class__._rules:
> func.__class__._rules.append(func)
> print testis._rules
> return func
> @rule
> def arule(self):
> print a
>
> Of course it doesn't work. Is there a way to make it work? What I am
> trying to do is make a collection of validation rules that can be
> iterated and capture raised exceptions to be returned at the end of
> eval rules.
Here is one way to do it. The rule() decorator just adds an attribute to the
function that marks it as a rule. You could also use a naming convention to
mark rules. The __init__ method uses inspection of dir(self) to find the rules.
Because dir() includes base class attributes it works with inherited rule
classes which IIRC was something you wanted.
def rule(func):
func.isRule = True
return func
class testObj(object):
def __init__(self):
self._rules = []
for name in dir(self):
item = getattr(self, name)
if getattr(item, 'isRule', False):
self._rules.append(item)
def evalRules(self):
for r in self._rules:
r()
@rule
def arule(self):
print 'This is a rule'
@rule
def brule(self):
print 'This is another rule'
t = testObj()
t.evalRules()
class testObj2(testObj):
@rule
def arule(self):
print 'This is a new version of arule'
t = testObj2()
t.evalRules()
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