ssanj

List("one", "two", "three") map (_.length)

trait Functor[F[_]] {
 def fmap[A,B](f: A => B, fa:F[A]): F[B]
}

class ListFunctor extends Functor[List] {
  def fmap[A,B](f: A => B, fa:List[A]): List[B] = fa match {
    case Nil => Nil
    case x::xs => f(x) :: fmap(f, xs)

ssanj

case class Person(name:String)
fmap((_:Person).name, Holder(Person("Harry Potter")))
11: error: could not find implicit value for parameter functor: Functor[Holder]

ssanj

List -> is a type constructor
List[Long] -> is a type

ssanj

scala> val ar:List[Int] = Nil
ar: List[Int] = List()

scala> "blah" :: 5 :: 6 :: ar
res21: List[Any] = List(blah, 5, 6)

//how did I add a String to a List[Int]?
//how do you keep the type within the List fixed at Int?
//can I only do that at declaration time as opposed to when I call the :: method?
//This works:

ssanj

;; Load the ensime lisp code...
(add-to-list 'load-path "ENSIME_ROOT/elisp/")
(require 'ensime)

;; This step causes the ensime-mode to be started whenever
;; scala-mode is started for a buffer. You may have to customize this step
;; if you're not using the standard scala mode.
(add-hook 'scala-mode-hook 'ensime-scala-mode-hook)

;; MINI HOWTO: 

ssanj

Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

ssanj

sudo iptables -A CHAIN_NAME

ssanj

sudo chmod +x /etc/network/if-pre-up.d/iptablesload

ssanj

cabal install hlint
Resolving dependencies...
[1 of 1] Compiling Main             ( /var/folders/zn/7pk0j2jd3d5b35n46ybls6s80000gn/T/haskell-src-exts-1.11.15274/haskell-src-exts-1.11.1/Setup.hs, /var/folders/zn/7pk0j2jd3d5b35n46ybls6s80000gn/T/haskell-src-exts-1.11.15274/haskell-src-exts-1.11.1/dist/setup/Main.o )

/var/folders/zn/7pk0j2jd3d5b35n46ybls6s80000gn/T/haskell-src-exts-1.11.15274/haskell-src-exts-1.11.1/Setup.hs:1:0:
    Warning: In the use of `runTests'
             (imported from Distribution.Simple, but defined in Distribution.Simple.UserHooks):
             Deprecated: "Please use the new testing interface instead!"
Linking /var/folders/zn/7pk0j2jd3d5b35n46ybls6s80000gn/T/haskell-src-exts-1.11.15274/haskell-src-exts-1.11.1/dist/setup/setup ...
Configuring haskell-src-exts-1.11.1...

ssanj

Given: uncurry id

the result is: (b -> c, b) -> c

How does this result come about?

uncurry :: (a-> b -> c) -> (a,b) -> c
id :: a -> a

How can you use id (a -> a) as the first parameter to uncurry, which requires a (a -> b -> c) function?