nkpart

Joining CSV Tables in Haskell

This article describes a technique for joining (in an SQL-style) lists of haskell data structures.

Maybe not the fastest, maybe not the smartest, but it works.

Why I like it

nkpart

{-# LANGUAGE NoMonomorphismRestriction #-}
{-# LANGUAGE TemplateHaskell           #-}
{-# OPTIONS_GHC -fwarn-missing-methods #-}
module Err where

import Control.Lens
import Control.Monad.Error
import Control.Monad.Error.Lens

-- Here is a fairly typical situation, where we have low level errors in certain