Declarative setting of validation rules

[Nettsentrisk]

Like the declarative nature of providing error messages, it should be possible to set validation rules on inputs declaratively.

jQuery Validation has a data-rule-* format for these, where you can pass settings in to the validation rule in the attribute value, if necessary.

As far as I can see from the code as it is now, you'd have to iterate over all the inputs that need a custom validator and pass them through the addValidator method one by one.

[Boldewyn]

I'm not against such a feature (and implemented things like that myself several times), but what would be a rule that one could add, and that cannot be built with a combination of existing attributes like pattern? Or would that be a general-purpose rule like creditcard or phoneUS like in jQuery Validation?

The point why I'm a bit hesitating is, that I plan with #14 to open up the inner workings of Hyperform, so one could write plugins, that could do things like, in the extreme case, add support for new type values. I haven't quite made up my mind how that will work out in the end, but I'd like to sort that out first, before implementing a rules feature.

[Nettsentrisk]

The "equalTo" validation from jQuery Validation is maybe a good example of this. Other use cases are when you need to validate something via an AJAX request (I have another issue filed for clarification/example of how this can be done with hyperform).