On 26 October 2017 at 07:30, Chris Barker <[email protected]> wrote:
> +1 on a classmethod constructor > +0 on a based-on-type default constructor > > +inf on SOMETHING! > > Let's get passed the bike shedding and make this work! > I'll also note that these aren't either/or outcomes: adding a str-specific classmethod *doesn't* preclude implicitly calling that class method from the default constructor later based on the input type. For example, decimal.Decimal.from_float() was added before the type constructor gained native support for float inputs, due to concerns about potential binary-vs-decimal rounding errors arising from doing such conversions implicitly. So we can add "datetime.fromisoformat(isotime: str)" now, and then *if* we later decide to support the "type(x)(str(x)) == x" numeric invariant for the datetime classes, that can be specified as "If the constructor arguments consist of a single string, that is handled by calling the fromisoformat class method". Cheers, Nick. -- Nick Coghlan | [email protected] | Brisbane, Australia
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