Raised by: Glen in mail.
Discussion: Glen: "For date and time types ... type of color ... type of range the assignment is only allowed if it is a valid ..." On our call we discussed how these grammars are hints, and in particular how pattern may be difficult to implement. We discussed that showing an output response, even an invalid one, may be more valuable than no response.
Michael: We can do hints for patterns on text, and for numbers out of range, but for other types HTML5 is just too strict to allow it. See date and time state for one such example. From the HTML 5 text:
If the element is mutable, the user agent should allow the user to change the global date and time represented by its value, as obtained by parsing a global date and time from it. User agents must not allow the user to set the value to a non-empty string that is not a valid global date and time string expressed in UTC, though user agents may allow the user to set and view the time in another time zone and silently translate the time to and from the UTC time zone in the value. If the user agent provides a user interface for selecting a global date and time, then the value must be set to a valid global date and time string expressed in UTC representing the user's selection. User agents should allow the user to set the value to the empty string.
So I think that constrains us. We might still allow a reco of "brown" in a date field in the match event, but then when the binding comes I think we are constrained but the "user agents must not allow" which would fail that binding. The states of type has all the various rules spelled out.
Resolution: Refer to issue 11 and include examples of where the problems are.