James Maggs Jazzatola

Jazzatola / Identity.scala

Created March 2, 2018 12:57

Identity Monad

	package com.jamesmaggs.monads

	trait Identity[A] { self =>

	def run: A

	def map[B](f: A => B): Identity[B] =
	new Identity[B] { def run = f(self.run) }

	def flatMap[B](f: A => Identity[B]): Identity[B] =

Jazzatola / Example.scala

Created April 25, 2015 16:11

How do I make this compile? I must be missing a type bound somewhere...

Jazzatola / PimpMyPredicate.scala

Last active August 29, 2015 14:19

	package org.example

	case class PimpMyPredicate[A](f: A => Boolean) {
	def &&(g: A => Boolean): A => Boolean = a => g(a) && f(a)
	}

	object PimpMyPredicate {
	implicit def enrichPredicate[A](f: A => Boolean): PimpMyPredicate[A] = PimpMyPredicate(f)
	}

Jazzatola / CPS.scala

Created January 28, 2015 17:27

Continuation Passing

	object CPS {

	def chainCps[A, B, R](f: ((A => R) => R), g: (A => ((B => R) => R))): (B => R) => R =
	(h: B => R) => f(a => g(a)(h))

	}

Jazzatola / Mapper.scala

Created January 21, 2015 20:59

Tail recursive map implementation

	package org.example

	import scala.annotation.tailrec

	object Mapper {

	@tailrec
	def foldLeft[A, B](as: List[A], z: B)(f: (B, A) => B): B = as match {
	case Nil => z
	case a :: as => foldLeft(as, f(z, a))(f)

Jazzatola / Liskov.scala

Last active August 29, 2015 14:13

Using covariant and contravariant types to demonstrate the Liskov substitution principle

	package com.example

	class GrandParent
	class Parent extends GrandParent
	class Child extends Parent

	/*
	* contravariant parameter p
	* covariant result r
	*/

Jazzatola / app.rb

Last active December 17, 2015 22:58

Minimal sinatra app exposing suspected bug in warden. The callback is not called when logging out.

	require 'sinatra'
	require 'warden'

	class User

	def initialize(id = nil)
	@id = id
	end

	def self.find_by_username(username)

Jazzatola / random_colors.html

Created February 1, 2013 17:06

Random colours animated with jquery.

	<html>
	<head>
	<title>Random Colors</title>
	<script src="http://code.jquery.com/jquery-1.9.0.min.js"></script>
	<script src="http://code.jquery.com/ui/1.10.0/jquery-ui.js"></script>
	<style type="text/css">
	body {
	margin: 0;
	}