https://github.com/stlab/adobe_source_libraries/blob/7659244...

https://listarchives.boost.org/Archives/boost/2013/01/200366...

I gotta say, I don't see the greatness any more than most of the repliers in that Boost thread — it's just two stable_partitions in a row.

"[...] Or is there some optimization that gather provides over (stable_)partition? —— Nope. [...]"