map -package:containers -package:charset -package:Cabal-syntax -package:insert-ordered-containers -package:incipit-base -package:dlist -package:case-insensitive -package:bytestring -package:imports -package:base-compat -package:os-string -package:filepath package:basement is:exact
Map all element a from a block to a new block of b
Map all elements in a list