- From: Julian Reschke <julian.reschke@gmx.de>
- Date: Fri, 05 Jun 2009 10:42:16 +0200
Ian Hickson wrote: > On Fri, 5 Jun 2009, Julian Reschke wrote: >> Ian Hickson wrote: >>>> Michael(tm) Smith wrote: >>>>> It seems pretty clear that there isn't anything else to refer to for >>>>> the date/time parsing rules -- but to me at least, specifying those >>>>> rules seems orthogonal to specifying the date/time syntax, and I >>>>> would think the syntax could just be defined by making reference to >>>>> the productions[1] in RFC 3339 (instead of completely redefining >>>>> them), while stating any exceptions. >>>>> >>>>> [1] http://tools.ietf.org/html/rfc3339#section-5.6 >>>>> >>>>> I think the exceptions might just amount to: >>>>> >>>>> - the literal letters T and Z must be uppercase >>>> Any technical reason why they have to? >>> Not really. We just need a separator. >> So why make it different from RFC 3339? > > Limiting the syntax to the simplest possible syntax was an intentional > design choice intended to ease the burden on implementors and authors. In > practice, pretty much every time we've made syntax case-insensitive, we've > ended up having trouble because of it. If this was a totally new syntax, I would agree. But as something based on ISO8601 (and thereby also RFC 3339) it appears to be a bad idea to make it less compatible just for that reason. >>>>> - a year must be four or more digits, and must be greater that zero >>>> "a year must be four or more digits" -- sounds like an alternative >>>> format that an additional RFC, updating RFC 3339 could specify. >>>> >>>> "must be greater that zero" -- that's not syntax :-) >>>> >>>> So yes, I think referring to RFC 3339, even if it's just a narrative >>>> mention, would be good. >>> Why? >> Because it explains to readers how this is different. That is important >> because it's natural to look for existing libraries to parse date formats. > > The HTML5 spec defines exactly how to parse dates. Implementors are > required to implement what the spec describes, so reusing libraries is > implicitly not likely to be useful here. RFC3339 isn't even a particularly > important one in the grand scheme of things (ISO8601 comes to mind as a > much higher-profile example). I think it's unfortunate that HTML5 doesn't allow using an off-the-shelf parser. But if it doesn't, and the temptation *will* be there to use them, I'd recommend stating it very clearly. > I'm certainly not proposing to go through every date format spec and > explain how the rules in HTML5 differ from those rules. That is the kind > of material that belongs in support documents. BR, Julian
Received on Friday, 5 June 2009 01:42:16 UTC