map -package:containers -package:base-compat -package:Cabal-syntax -package:base-compat-batteries is:exact -package:ghc -package:blaze-html -package:charset -package:bytestring -package:monoidal-containers -package:case-insensitive -package:aeson package:basement
Map all element a from a block to a new block of b
Map all elements in a list