Data.Graph transitive closure

[Johannes Waldmann]

Hi,

> I looked at doing this in a "principled" way a long time ago.
> I then got distracted by something else..... 

You don't say :-)

Well, short-term suggestion (for containers:Data.Graph)
don't change existing code,
but improve documentation and do some benchmarking
https://github.com/haskell/containers/issues/648
https://github.com/haskell/containers/issues/649

@David: perhaps you can label these issues as "nice to have"
so it does not look like "bugs that need fixing".
Benchmarking would make for a nice student project?
In fact, I will pitch this to my current class.

- Johannes