xfire

import Control.Monad.Error

execAna :: Int -> ErrorT String IO (Int, Int)
execAna 0 = throwError "ERROR"
execAna n = return (n - 1, n + 1)

report :: Either String () -> IO ()
report (Left err) = putStrLn $ "failed: " ++ err
report _ = putStrLn "complete"

xfire

{-# LANGUAGE GeneralizedNewtypeDeriving #-}

import Control.Monad.Reader
import Control.Monad.State
import Control.Monad.Writer

-- our monad transformer stack
--   a reader with an prefix string for the log
--      a state with the current value as integer
--         a writer to log the work done

xfire

import Control.Monad.Reader
import Control.Monad.State
import Control.Monad.Writer

-- our monad transformer stack
--   a reader with an prefix string for the log
--      a state with the current value as integer
--         a writer to log the work done
--            all in a IO monad
type Prefix = String

xfire

{- xmobar util to read temperature on lenovo notebooks
 - 
 - usage:
 -   , Run Com "/home/fire/.xmonad/ibm_temp" ["40", "#B6B4B8", "red"] "temp" 10
 -}

import System( getArgs )
import Data.Maybe
import Control.Monad
import Control.Applicative

xfire

import Data.Foldable as F

-- our data structure
data Tree a = Empty
            | Node (Tree a) a (Tree a)
            deriving Show

-- a step on the way through our tree.
-- either going to the left or to the right.
data Direction a = DLeft a (Tree a)

xfire

-- little helper function
-- f3 (f2 (f1 x)) == x -: f1 -: f2 -: f3
(-:) x f = f x

-- the list zipper simply split the list in two parts.
type ListZipper a = ([a], [a])

makeListZipper :: [a] -> ListZipper a
makeListZipper l = (l, [])

xfire

-- little helper function
-- f3 (f2 (f1 x)) == x -: f1 -: f2 -: f3
(-:) x f = f x

-- our data structure
data Tree a = Empty
            | Node (Tree a) a (Tree a)
            deriving Show

-- a step on the way through our tree.

xfire

trait Foo[TC[_], V]

/* compilation error
 * -----------------
 * view_bound_error.scala:11: error: type T takes type parameters
 * def viewBound[T[V] <% Foo[T, V], V](value: T[V]) = value
 *                    ^
 * one error found
 */
def viewBound[T[V] <% Foo[T, V], V](value: T[V]) = value

xfire

class Foo(val a: Int, val b: String) {
  private var _c: Int = 42  // fuer die meisten default
  def c: Int = _c

  def this(a: Int, b: String, c: Int) = {
    this(a, b)
    _c = c
  }
}

xfire

data Tree a = Node (Tree a) (Tree a)
            | Leaf a
            deriving Show

instance Functor Tree where
    fmap g (Leaf v)   = Leaf (g v)
    fmap g (Node l r) = Node (fmap g l) (fmap g r)

sampleTree :: Tree String
sampleTree = Node (Node (Leaf "hello") (Leaf "foo")) (Leaf "baar")