Expose formatting functions used for formatting error messages

[jacobbuck]

Exposes 2 methods:

Backbone.Validation.formatFunctions.formatLabel(attrName, model)
Backbone.Validation.formatFunctions.format()

Useful for writing method validators or custom validators which use default messages.

[platinumazure]

Rather than jump into this, I'd like to discuss if it makes sense to unify standard and custom error message processing first.

To me it would be awesome if messages were all (under the hood) functions which take similar arguments to the validators themselves. Maybe strings with numeric formatting markers could be special-cased to invocations of the format function.

Exposing formatLabel isn't a bad idea, though.

Just my 2¢.

[jacobbuck]

@platinumazure I agree. But this is just a short term fix until that's a reality.

[chiefGui]

What do you think guys about a Dictionary of messages?

[platinumazure]

@chiefGui What sort of thing are you thinking of? Care to write a quick example? (Pseudocode is fine)

[chiefGui]

@platinumazure you told:

[...] unify standard and custom error message processing first [...]

For me, it makes lots of sense. Same interface: a dictionary. Something like errorMessages.json with key:value design.

If you stop and think about it, it turns globalization way easier.

Can you understand my point of view?

PS: I am saying this for empiricism. Once upon a time I needed validation messages in multiple languages and I got frustrated to deal with since the native foundation doesn't give me a solid — and easy — way to go.

At last, do you really think we have to create an interface to release this PR?

[platinumazure]

@chiefGui It's probably okay to release this as is, sure. I just wanted to make sure the concept was discussed.

Let's move further discussion to a new issue. I apologize for leading us down the rabbit hole in the first place.

[jacobbuck]

@thedersen any movement on this?

[jacobbuck]

@thedersen bump