Synnefo

    def parse(self, item):

        opts = self.opts

        if item is None and 'default' in opts:

            item = opts['default']

        can_be_null = opts.get('null', False)

        if item is None and can_be_null:

            return None

        return self._parse(item)

    def _parse(self, item):

        raise NotImplementedError

    def _parse(self, item):

        return self.check(item)

    def _parse(self, item):

        return self.check(item)

    def _parse(self, item):

        if item is None:

            item = ()

        try:

            items = iter(item)

        except TypeError, e:

            m = "%s: %s is not iterable" % (self, shorts(item))

            raise CanonifyException(m)

        canonical = self.canonical

        canonified = []

        append = canonified.append

        for k, v in items:

            item = canonical.parse(v)

            append(item)

        if not canonified and self.opts.get('nonempty', False):

            m = "%s: must be nonempty" % (self,)

            raise CanonifyException(m)

        return canonified

    def _parse(self, item):

        try:

            items = list(item)

        except TypeError, e:

            m = "%s: %s is not iterable" % (self, shorts(item))

            raise CanonifyException(m)

        canonicals = self.args

        zi = len(items)

        zc = len(canonicals)

        if zi != zc:

            m = "%s: expecting %d elements, not %d (%s)" % (self, zc, zi, str(items))

            raise CanonifyException(m)

        g = (canonical.parse(element)

             for canonical, (k, element) in zip(self.args, item))

        return tuple(g)

    def _parse(self, item):

        try:

            item = dict(item)

        except TypeError:

            m = "%s: '%s' is not dict-able" % (self, shorts(item))

            raise CanonifyException(m)

        canonified = {}

        canonical = self.kw

        for n, c in canonical.items():

            if n not in item:

                m = "%s: key '%s' not found" % (self, shorts(n))

                raise CanonifyException(m)

            canonified[n] = c(item[n])

        strict = self.opts.get('strict', True)

        if strict and len(item) != len(canonical):

            for k in sorted(item.keys()):

                if k not in canonical:

                    break

            m = "%s: unexpected key '%s' (strict mode)" % (self, shorts(k))

            raise CanonifyException(m)

        return canonified