Add FloatField in newforms

[jay.baird@…]

Not sure if this should be wrapped up in a patch, or what, but I just thought I'd put this out there in case anyone wanted to use it.

import re
import decimal
from django.newforms import *

float_regex = re.compile(
    r'\d+.\d+'
)

class FloatField(RegexField):
    def __init__(self, max_digits=None, decimal_places=None,max_value=None, min_value=None, required=True, widget=None, label=None, initial=None):
        self.max_value, self.min_value = decimal.Decimal(max_value or 'inf'), decimal.Decimal(min_value or '-inf')
        self.max_digits, self.decimal_places = max_digits, decimal_places
        RegexField.__init__(self, regex=float_regex, error_message="Please enter a valid decimal number", required=required, widget=widget, label=label, initial=initial)
        
    def clean(self, value):
        super(FloatField, self).clean(value)
        digits,decimals = value.split(".") 
        if not self.required and value in EMPTY_VALUES:
            return u''
        try:
            value = decimal.Decimal(value)
        except:
            raise ValidationError("Enter a decimal number")
        if self.max_value is not None and value > self.max_value:
            raise ValidationError("Ensure that value is less than or equal to %s" % self.max_value)
        if self.min_value is not None and value < self.min_value:
            raise ValidationError("Ensure that value is greater than or equal to %s" % self.min_value)
        if self.max_digits is not None and len(digits) > self.max_digits:
            raise ValidationError("Ensure that the number of digits is less than or equal to %s" % self.max_digits)
        if self.decimal_places is not None and len(decimals) > self.decimal_places:
            raise ValidationError("Ensure that the number of decimal places is less than or equal to %s" % self.decimal_places)
        return value

[jay.baird@…]

I'm not sure which is preferred in Django itself, Decimal or float(). If you're trying to keep backwards compatibility with 2.3 then this version is out, but with float() you get the dreaded 3.4 being expressed as 3.99999999998.

Any thoughts?

[James Bennett]

I can't speak to this suggestion one way or another, but in the past patches have been rejected which relied on the decimal module, in order to maintain compatibility with (the still widely-deployed) Python 2.3.

[jay.baird]

Yeah, since after looking at the way FloatField in the model.Fields handles things I'd replace that with float() for sure now.

[Waylan Limberg <waylan@…>]

This probably needs to be considered in relation to ticket #2365 (models.FloatField should be renamed). Whatever happens there should happen here so that FloatFields can match with FloatFields and DecimalFields with DecimalFields

[adurdin@…]

Yes, I'll incorporate this with the new patch for #2365 as the newforms FloatField.

[adurdin@…]

Should this be closed in favour of #2365?

[Jay Baird]

Not sure. It's there and ready to go, but it still hasn't been looked at by Adrian who's the principle on newforms. Anyone at PyCon want to get together and talk about it?

[Malcolm Tredinnick]

See #4004 for an alternative patch.

[Malcolm Tredinnick]

Closing as a dupe of #2365, since this patch has been incorporated there and looks reasonable.