Functions in bindings seem to be called twice

[robdodson]

Looking at this example:
http://jsbin.com/niteta/6/edit

The sublist function is always called twice, regardless of what it actually does or returns.

[sjmiles]

Just a note that this appears to be an issue with filters generally. It happens whether using pipe or function syntax.

[nevir]

Interestingly, and seemingly related: we're binding to the output of that function, which seems like it has the potential to be severely confusing: http://jsbin.com/koviji/1/edit

Should it be binding at all? Seems like it should be binding, at most, to the function itself (too magic otherwise?).

[sjmiles]

@jmesserly or @ajklein ... maybe you can review? Seems good to get this fixed asap.