Enhancement: allow ":once" on event names to indicate one() variant event binding

[getify]

I am a big fan of the "one()" functionality. But I have a suggestion for a small piece of sugar to extend it:

Allow me to put ":once" on the end of any event name in any of the event binding APIs (bind, on, etc) which tells jQuery to use the "one()" variant for the binding of that particular event. For example:

$("a").bind("click:once",handle)
// vs. $("a").one("click",handle)

$("#foobar").on("mousedown:once mouseup","a",handle)
// vs. $("#foobar").one("mousedown","a",handle).on("mouseup","a",handle)

[dmethvin]

There might be a case to be made for a CSS-selectors-like handling of the event string, but I'm not a fan of making an exception for ":once" alone. Also, many external users are now using the ":" character in their custom event strings so we would need to be very careful about creating compatibility issues. I'll mark it for 1.9 discussion.

[getify]

FWIW, Mootools has a whole system of "Event Pseudos", including ":once"...

 http://mootools.net/docs/more/Class/Events.Pseudos

Perhaps that's a pattern jQuery could consider for this.

[dmethvin]

-1, This doesn't fit in at all with our string event syntax, and the colon char is used by frameworks.

[mikesherov]

-1, Seems almost too late for jQuery to do this now.

[gibson042]

-1, I'd rather not mix extra logic into event type.

[mikesherov]

-1

[rwaldron]

-1, No new custom selectors. No new event system complexities

[gibson042]

-1

[gnarf]

-1, Dave brings up points I agree with