map is:exact -package:bytestring -package:dense-linear-algebra -package:blaze-html -package:incipit-base -package:base-compat -package:Cabal-syntax -package:filepath -package:conduit -package:base-compat-batteries -package:monoidal-containers -package:case-insensitive package:basement
Map all element a from a block to a new block of b
Map all elements in a list