Map, Flatten and FlatMap

I've recently been working with some developers who are new to the Scala world. They've picked up the language really easily and in only a few week have become competent Scala developers. Who says it's too complex and difficult to learn?

Anyway, one of these developers is a visual thinker such as myself. We prefer communication through diagrams rather than words. While explaining Scala I've been drawing some pictures to illustrate some of the more interesting concepts. She suggested that I should publish these and we had the idea that an animation would be fun.

Here's my first animated post showing the concepts for Map, Flatten and FlatMap. It's a pretty amiturish stab at animation, but hopefully it explains the concepts while also adding a bit of humour along the way.

If you are interested here's the Scala code for the concepts covered in the animation:

case class World[+A](revolvesAround: A) {

  def map[B](f: A => B): World[B] = World(f(revolvesAround)) 

  def flatten[B](implicit ev: A <:< World[B]): World[B] = World(revolvesAround.revolvesAround)

  def flatMap[B](f: A => World[B]) = World(f(revolvesAround).revolvesAround)

  def get: A = revolvesAround
}

def lift[A](entity: A): World[A] = World(entity)

case class Person(name: String) {
  def smite = DeadBody(name)
}
case class DeadBody(usedToBe: String)
case class Insect(species: String)

def kill(p: Person): DeadBody = p.smite
def reincarnate(b: DeadBody): World[Insect] = World(Insect("ant"))

val dave: Person = Person("Dave")
val antDave: Insect = lift(dave) map kill flatMap reincarnate get 

println(antDave)

The Elusive Inspiration

I'm currently working on a software idea that I have had running around in my head for a number of years. It's based around concepts for classification of information, exploration of relationships between this information and how this changes over time. The domain model is fairly complex as I want to keep it fairly generic and configurable so that individual users can customise it for their own types of information and classifications.

Unfortunately I have come up against a mental block when it comes to this domain model. I think that the ideas have been going round in my head for so long and I have so many different variations and alternatives that I  just can't find a way to move forward with something concrete.

This has got me thinking about the mental process and how to unblock my creative self on this project. To this end I've been considering the following ideas...

Go Away and Do Something Else
Often I find that if I can't get my head around something then going off and doing a different project for a while allows my brain time to unwind and process my ideas in the background. After a while I then come back to my original project and more often than not this allows me make good progress. However, on this current project I've been going off and doing something else for ages and it's time I made some progress.

Go For a Thinking Walk
I love walking - especially going somewhere I haven't been before and just exploring. Often I find that during a walk of this type I am able to focus and concentrate on a single topic until I come to some form of resolution. I think I'll try this one at lunchtime today.

Whiteboard Session
I am a very visual person. I find exploring concepts on a whiteboard a great solution for fleshing out designs and examining alternatives. I love colours as well and often find a visual with different element types in different colours really clarifies my understanding. This will probably be my next approach to explore the results of my thinking walk.

Exploratory Coding
Sometimes even the best thinking and most perfect whiteboard drawings just don't capture the essence of a problem. At times like these a couple of hours of hacking out an exploratory solution in code can clarify all sorts thoughts and ideas. When doing this sort of coding I like to use a very dynamic language (Ruby is my general choice) as I find these allow me to capture lots of thinking in a short amount of time.  Increasingly I'm also doing exploratory coding in a Functional language (usually Haskell) as I find this a great way to structure my thinking.

Test Driven Development
A completely alternative approach is to avoid all the up front thinking of how the domain model will work. Instead, define some test cases that describe what the domain model should do and then derive the model out of these tests. My final implementation will certainly be carried out in this way, but for the moment I'm still thinking at a higher level. I feel that I need to better understand exactly what I'm trying to achieve before writing production code.

How do you resolve mental block issues such as these? What other techniques are available?

Additions:


Build a Mind Map
Another thought that I had was to build a mind map to explore all of the thoughts and alternatives. By restricting this mind map to just the domain model that I am interested in I might be able to look at the problem in a new light. I use ConceptDraw MINDMAP on my Mac for this purpose.