overriding validate_python (and similar methods) in validators

Hello.  I'm a bit new to FormEncode, so pardon me if I'm bringing up
an old chestnut or need to be set straight about something.

I recently had a bunch of custom validators, subclassing
FancyValidator or one of its subclasses (Regex, for instance), and
then I found a bug in one of them -- I overrode validate_python but
didn't call the same method on the superclass, so didn't get the
complete validation.  (I believe this was a Regex subclass.)  So I
went through my validators and made sure that whenever I wrote a
validate_python method, I called the corresponding superclass method.
Then I tried running it, and whoah!  for some but not all of the
validators, this gave rise to an error, because validate_python in
FancyValidator is None.

I take it that the reason FormEncode allows validate_python et al to
have the value of None is to support a declarative programming style.
But to my mind the use of this feature in FancyValidator, a base
class, makes the interface it presents rather confusing and
unpredictable, and, I think, results in an excessively leaky
abstraction.  Couldn't these methods be defined there as noops, or
would that have side-effects I'm unaware of?

js

-- 
Jacob Smullyan
office: 212/669-3230
mobile: 917/576-5274

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