map is:exact -package:text -package:dense-linear-algebra -package:aeson -package:Cabal-syntax -package:blaze-html -package:dlist -package:ghc -package:bytestring -package:integration -package:insert-ordered-containers -package:base-compat-batteries -package:conduit package:basement
Map all element a from a block to a new block of b
Map all elements in a list