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