Declaring columns in Frames

Cocreature.hs

{-# LANGUAGE OverloadedStrings, QuasiQuotes, RankNTypes #-}
{-# LANGUAGE DataKinds, FlexibleContexts, TemplateHaskell, TypeOperators #-}
import Frames
import Frames.ColumnUniverse
import Frames.CSV
import Lens.Family
import Pipes

-- Manually declared columns using a TH helper
declareColumn "x2" ''Double
declareColumn "y" ''Int

type Data2 = Record '[X1, X2, Y]

-- Manually declared column with no help
type X1 = "x1" :-> Double
x1 :: (forall f. Functor f => (Double -> f Double) -> Data2 -> f Data2)
x1 = rlens [pr|X1|]

data2Parser = defaultParser { headerOverride = Just [] }

data2Stream :: Producer Data2 IO ()
data2Stream = readTableOpt data2Parser "data/ex1data2.txt"

loadData2 :: IO (Frame Data2)
loadData2 = inCoreAoS data2Stream

mean :: Frame s -> (s -> Double) -> Double
mean d col = sum (col <$> d) / (fromIntegral $ frameLength d)