gistfile1.purs

module Data.PhoneBook where

import Data.List
import Data.Maybe

import Control.Plus (empty)

type Entry = { firstName :: String, lastName :: String, phone :: String }

type PhoneBook = List Entry

showEntry :: Entry -> String
showEntry entry = entry.lastName ++ ", " ++
                  entry.firstName ++ ": " ++
                  entry.phone

emptyBook :: PhoneBook
emptyBook = empty

insertEntry :: Entry -> PhoneBook -> PhoneBook
insertEntry = Cons

filter :: (Entry -> Boolean) -> PhoneBook -> PhoneBook
head :: PhoneBook -> Maybe Entry

findEntry :: String -> String -> PhoneBook -> Maybe Entry
findEntry firstName lastName book = head <<< filter filterEntry
  where
  filterEntry :: Entry -> Boolean
  filterEntry entry = entry.firstName == firstName && entry.lastName == lastName