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