dvdsgl

fs = require 'fs'

class MyClass

  # Trying to create middleware with access to class members.
  withData: (cb) -> 
    return cb @__data if @__data?
    fs.readFile 'datafile.json', (err, json) =>
      throw err if err?
      @__data = JSON.parse json

dvdsgl

web: node server.js

dvdsgl

findRoots 0 b c = Nothing
findRoots a b c = Just ((-b + d) / 2*a, (-b - d) / 2*a)
  where d = sqrt (b^2 - 4*a*c)

main = print (findRoots 1 6 8)

dvdsgl

-- findRoots is a function that takes 3 Doubles and maybe returns a tuple of doubles.
-- Here's its signature, which can be omitted because Haskell infers it:
findRoots :: Double -> Double -> Double -> Maybe (Double, Double)

-- In a C-like language with parameterized types, the type signature might look like:
--
-- static Maybe<Tuple<double,double>> findRoots(double a, double b, double c);
--
-- Maybe is Haskell's 'nullable type'; values of type Maybe t can be thought of as lists
-- containing exactly zero or one value of type t. So, a Maybe Double is either zero or

dvdsgl

// Register an API key in your AppDelegate's FinsihedLaunching method:
// GMSServices.ProvideAPIKey ("Your API key.");

GMSMapView mapView;

public override void ViewDidLoad ()
{
    base.ViewDidLoad ();
    
    // Create the map view, framing Xamarin headquarters

dvdsgl

// Demo:
//
// let files = sh "ls -a /Users/david" |> lines
// let install = sh "cp -r %s /Applications"
// install "/Volumes/Awareness/Awareness.app"
//

module Campari.Shell

open System

dvdsgl

// I see this a lot in F# code:

control.OnClick.Add (fun _ ->
  printfn "%A was clicked" control
)

// The entire lamda is parenthesized so it can be
// passed to Add, resulting in an ugly, dangling ')'.

// F# has a reverse pipeline operator called <| that's

dvdsgl

type FizzBuzz =
  FizzBuzz | Fizz | Buzz | Nat of int

let (|DivisibleBy|_|) by n =
  if n % by = 0 then Some () else None

let fizzbuzz n = match n with
  | DivisibleBy 3 & DivisibleBy 5 -> FizzBuzz
  | DivisibleBy 3 -> Fizz
  | DivisibleBy 5 -> Buzz

dvdsgl

public static class RectangleExtensions
{
  public static RectangleF With (this RectangleF self,
                                 float? X = null, float? Y = null,
                                 float? Width = null, float? Height = null)
  {
    return new RectangleF (X ?? self.X, Y ?? self.Y, Width ?? self.Width, Height ?? self.Height);
  }
  
  static T Id<T> (T t) { return t; }

dvdsgl

#r "Volare.dll"

open Volare

get "/" <| fun req res ->
  "Hello, world!"

get "/:name" <| fun req res ->
  html <| fun _ ->
    body <| fun _ ->