map is:exact -package:text -package:containers -package:bytestring -package:case-insensitive -package:invertible -package:dlist -package:incipit-base -package:base-compat-batteries -package:hedgehog -package:ghc -package:conduit -package:dense-linear-algebra package:basement
Map all element a from a block to a new block of b
Map all elements in a list