George Sakkis wrote:
> That's a typical case for using an OO approach; just make a class for
> each validator and have a single polymorphic validate method (I would
> make validators __call__able instead of naming the method 'validate'):
>
> # Abstract Validator class; not strictly necessary but good for
> documentation
> class Validator(object):
> def __call__(self,field,value):
> '''Validate a value for this field.
> Return a string representation of value on success, or None on
> failure.
> '''
> raise NotImplementedError("Abstract method")
>
>
> class DecimalValidator(Validator):
> def __call__(self,name,value):
> '''Test whether numeric value is a decimal.'''
Why is this better than an isDecimal function?
def isDecimal(name, value):
''' Test whether numeric value is a decimal.'''
seems simpler and more straightforward to me.
> def validateField(name, value, validators):
> """ Validates field input """
> results = {}
> for validate in validators:
> result = validate(name,value)
> if result is not None:
> results[name] = result
> # XXX: if more than one validators succeed,
> # all but the last result will be overwritten
> return results
No change needed in the loop above...
>
> # test
> validators = [DecimalValidator(), ZipCodeValidator()]
validators = [ isDecimal, isZipCode ]
Kent
--
http://mail.python.org/mailman/listinfo/python-list
