map is:exact -package:text -package:base-compat-batteries -package:containers -package:amazonka-core -package:Cabal-syntax -package:invertible -package:base-prelude -package:incipit-base -package:bytestring -package:dlist -package:dense-linear-algebra -package:os-string package:basement
Map all element a from a block to a new block of b
Map all elements in a list