Greets,

Attached is a new patch addressing nits.

Still open questions from the other thread:

  * Is is possible to make a Maybe<UnwindInfo>-style interface to
    sniffers, or should extension languages expose the callbacks
    instead because they really need to be called within their specific
    dynamic environments?

    (Clearly it's possible, to the extent that Alexander and I have done
    it, but is it a good idea?  It sure would be nice, if so :)

  * Regarding recursion and selected frames -- what do you think about
    the hack in v2 of this patch, which adds
    frame_unwinder_is_unwinding() ?  It is a hack but it has somewhat
    reasonable semantics.

Regards,

Andy