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import { class, interface, implements } from 'sweet-interfaces';

const constant = x => _ => x;
const identity = x => x;
const flip = f => (a, b) -> f(b, c);

interface Setoid {
  // eq :: Setoid a => a ~> a -> Boolean
  eq(b) { return this === b; }
}

srdjan

// Sometimes, you might want to supply *some* config, but
// not necessarily *all*. Maybe your password is really
// secret, so you don't want to risk saving it in a config
// file. In which case, you'll want to ask the user to enter
// it when your script runs.

// This interface provides a flexible approach, where
// the user is prompted for a missing key when it's
// requested - if a particular key isn't needed for a given
// run, the user won't need to enter it. Of course, if the

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    var byMonth = R.groupBy(R.prop('Month'));
    var byAuthor = R.groupBy(R.prop('Author'));

    var royalty_key = 'Royalty (SUM)';

    var months_keys = R.uniq(R.map(R.prop('Month'), data)).sort();
    var monthly_revenue =
        R.map((group) => 
            R.reduce((acc, record) => acc + parseMoney(record[royalty_key]), 0, group),
        byMonth(data));

srdjan

CATEGORY THEORY FOR PROGRAMMERS

Category Theory 1.1: Motivation and Philosophy 
https://www.youtube.com/watch?v=I8LbkfSSR58&index=1&list=PLbgaMIhjbmEnaH_LTkxLI7FMa2HsnawM_

Composability, Abstraction, Reusability

Category Theory is a higher-level language.
Not a practical, executable language.

srdjan

const reg = new RegExp("([^?=&]+)(=([^&]*))?", "g")

function qs (uri) {
  const obj = {}
  uri = uri.replace(/^.*\?/, '')
  uri.replace(reg, map)
  return obj

  function map (a0, a1, a2, a3) {
    obj[decodeURIComponent(a1)] = decodeURIComponent(a3)

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type Request<'i,'o,'k> = 'i * ('o -> 'k)
let bindRequest bind f (s,k) = s, fun v -> bind(k v,f)

type Id = int
type Entity<'e> = Entity of Id option * 'e 
[<Measure>] type money
type User = {name : string; email : string; ballance : int<money>}
type Product = { name : string; quantity : int; price : int<money>}

type Email = {body:string; subject : string}

srdjan

/*eslint-env es6 */

// Inspired by the paper "A tutorial on the universality and
// expressiveness of fold" by Graham Hutton (available at
// http://www.cs.nott.ac.uk/~gmh/fold.pdf), implementing some generic
// list handling functions in JavaScript in terms of `fold`.

// Personally I had an enlightnening moment when I realised the
// beautiful interplay of cons lists and foldr during the FP101x
// Haskell course. JavaScript's syntax doesn't make this very apparent

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using System;
using System.Linq;
using Raven.Abstractions.Data;
using Raven.Abstractions.Logging;
using Raven.Bundles.Replication.Plugins;
using Raven.Json.Linq;

namespace RavenConflictResolverPlugin
{
    public class LastInWinsReplicationConflictResolver

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module BorrowABook = 
    type BookLoanProblem = 
        NotInCatalogue 
        | OutOnLoan
        | InsufficientPermission
        | Failed of string

    type Book = Book
    type BookModel = BookModel

srdjan

Is socket.push(bytes) all what you need to program Realtime Web apps?

One of the goals of Play2 architecture is to provide a programming model for what is called Realtime Web Applications.

Realtime Web Applications

Realtime Web Applications are applications making use of Websockets, Server Sent Events, Comet or other protocols offering/simulating an open socket between the browser and the server for continuous communication. Basically, these applications offer to users delivery of information as it is published without having the user periodically pinging the service.

There are quite a few web frameworks that target the development of this type of applications. Mostly, however, the solution is by providing an API that allows developers to push/receive messages from/to an open channel, something like: