map -package:containers -package:charset is:exact -package:insert-ordered-containers -package:base-compat-batteries -package:incipit-base -package:Cabal-syntax -package:ghc -package:case-insensitive -package:monoidal-containers -package:imports -package:foldl package:basement
Map all element a from a block to a new block of b
Map all elements in a list