[Haskell-cafe] do ghci

Just curious, why does ghci run in the context of a 'do'? This tripped me up when I first started learning Haskell. It's fine once you know what's going on, but why the restriction? Why can't I write the code below without 'let' and ':module'?

two = 1 + 1 import Data.List cols = transpose [[1,2,3], [4,5,6]]

Thanks, Greg