map -package:containers -package:charset -package:case-insensitive -package:dlist -package:aeson -package:Cabal-syntax -package:ghc -package:incipit-base -package:base-compat-batteries -package:base-prelude -package:dense-linear-algebra is:exact package:basement
Map all element a from a block to a new block of b
Map all elements in a list