[diegoperini]

Do ctrl-f for "Nested Operator Expressions" in this piece: https://martinfowler.com/articles/collection-pipeline/

Some other references helped me along the way:

* http://www.lihaoyi.com/post/WhatsFunctionalProgrammingAllAbo...

* http://learnyouahaskell.com/chapters

[atombender]

Reading a little more about it, I think the concatenation idea more properly fits with the join operator, which acts like a flatten function.