Re: using min and max with float

On Fri, May 2, 2008 at 8:30 AM, Ian Bicking <[email protected]> wrote:
> Re: Range -- perhaps that could be an abstract base class for Float and Int?

Yes, that's an excellent idea.  Duh ;)

My style is just slightly different than yours, but here's the code
with doctests and all:

class RangeValidator(FancyValidator):

    """This is an abstract base class for Int and Number.

    It verifies that a value is within range.  It accepts min and max
    values in the constructor.

    (Since this is an abstract base class, the tests are in Int and
    Number.)

    """

    messages = {
        'tooLow': _("Please enter a number that is %(min)s or greater"),
        'tooHigh': _("Please enter a number that is %(max)s or smaller"),
    }

    min = None
    max = None

    def validate_python(self, value, state):

        # There's some duplicated code here, but it's a lot more
        # readable than the alternative.

        if self.min is not None:
            if value < self.min:
                msg = self.message("tooLow", state, min=self.min)
                raise Invalid(msg, value, state)
        if self.max is not None:
            if value > self.max:
                msg = self.message("tooHigh", state, max=self.max)
                raise Invalid(msg, value, state)


class Int(RangeValidator):

    """Convert a value to an integer.

    Example::

        >>> Int.to_python('10')
        10
        >>> Int.to_python('ten')
        Traceback (most recent call last):
            ...
        Invalid: Please enter an integer value
        >>> Int(min=5).to_python('6')
        6
        >>> Int(max=10).to_python('11')
        Traceback (most recent call last):
            ...
        Invalid: Please enter a number that is 10 or smaller

    """

    messages = {
        'integer': _("Please enter an integer value")
    }

    def _to_python(self, value, state):
        try:
            return int(value)
        except (ValueError, TypeError):
            raise Invalid(self.message('integer', state),
                          value, state)

    _from_python = _to_python


class Number(RangeValidator):

    """Convert a value to a float or integer.

    Tries to convert it to an integer if no information is lost.

    Example::

        >>> Number.to_python('10')
        10
        >>> Number.to_python('10.5')
        10.5
        >>> Number.to_python('ten')
        Traceback (most recent call last):
            ...
        Invalid: Please enter a number
        >>> Number(min=5).to_python('6.5')
        6.5
        >>> Number(max=10.5).to_python('11.5')
        Traceback (most recent call last):
            ...
        Invalid: Please enter a number that is 10.5 or smaller

    """

    messages = {
        'number': _("Please enter a number")
    }

    def _to_python(self, value, state):
        try:
            value = float(value)
            if value == int(value):
                return int(value)
            return value
        except ValueError:
            raise Invalid(self.message('number', state),
                          value, state)

Best Regards,
-jj

-- 
I, for one, welcome our new Facebook overlords!
http://jjinux.blogspot.com/

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