example.hs

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE OverloadedLists #-}

module Main where

import qualified Data.ByteString as BS
import Data.HashMap.Strict (HashMap)
import Data.Text (Text)
import qualified Xmlbf as X
import qualified Xmlbf.Xeno as Xx

data AtomFeed = AtomFeed
  { feedName :: !Text
  , feedAttrs :: !(HashMap Text Text)
  , feedChildren :: ![X.Node]
  } deriving (Show, Eq)

instance X.ToXml AtomFeed where
  toXml = \(AtomFeed n as cs) ->
    let title = X.element' "atom:title" [] [X.text n]
    in [X.element' "atom:feed" as (title : cs)]

instance X.FromXml AtomFeed where
  fromXml = X.pElement "atom:feed" $ do
    title <- X.pElement "atom:title" X.pText
    attrs <- X.pAttrs
    pure (AtomFeed title attrs [])

rawFeed :: BS.ByteString
rawFeed =
  "<atom:feed xmlns:atom=\"http://www.w3.org/2005/Atom\">\
  \  <atom:title>ServicePlan Feed</atom:title>\
  \</atom:feed>"

expectedFeed :: AtomFeed
expectedFeed = AtomFeed
  { feedName = "ServicePlan Feed"
  , feedAttrs = [("xmlns:atom", "http://www.w3.org/2005/Atom")]
  , feedChildren = []
  }

actualFeed :: AtomFeed
Right actualFeed = X.runParser X.fromXml =<< Xx.nodes rawFeed

Ok, two modules loaded.                                                                                                                  
> expectedFeed                                                                                                                           
AtomFeed {feedName = "ServicePlan Feed", feedAttrs = fromList [("xmlns:atom","http://www.w3.org/2005/Atom")], feedChildren = []}         
> actualFeed                                                                   
AtomFeed {feedName = "ServicePlan Feed", feedAttrs = fromList [("xmlns:atom","http://www.w3.org/2005/Atom")], feedChildren = []}