lorenjohnson / jankenpon Goto Github PK

Otherwise know as “Rock, Paper, Scissors” this hand game has a Chinese origin and migrated and popularized in Japan long ago as a social way of settling disputes. In Japanese the symbols are the same and in Japaense are Jan, Ken, Pon.

Evidently in Japan babies learn this before they learn to speak and there is a common way of playing in large groups (20 people+) where a single winner is arrived at in a very short period of time.

This group version could have been a fun thing to study and implement. However, in the interest of time and in not “overdoing it” for what is intended as a simple exercise, I went the simpler route and focused on a clear implementation exhibiting a simple full-stack Rails implementation of one player vs computer.

Assuming you use RVM you should be able to just:

1. git clone [email protected]:lorenjohnson/jankenpon.git

2. bundle install

3. rails s

I’ve went with a fairly minimal interface, clock one of the human hands to play. Then wash and repeat. Each round is stored and presented below the currently played round with an accumulation of your winds in the current round to the left and the computer wins to the right.

To “Start Over” in the upper right corner (this will clear entries for your current session id).

1) Basic app setup:

> rvm use 1.9.3
> rvm gemset create jankenpon
> gem install rails
> rails new jankenpon
> cd jankenpon

<create .rvmrc NOTE: will force gemset creation> <edit Gemfile adding ‘haml-rails’>

> bundle install

2) Modeled the Jankenpon game “engine”.

I have a Round class, could have been Match, Game or Fist or something, but Round seemed reasonable enough.

I decided early-on to persist (sqlite3) rounds as when playing in reality with another person I can’t remember ever just playing once. It’s kinda a game of averages to me. (That, and as I chose to do this as a Rails app, well it’s just so easy to persist stuff.)

> rails g resource round

Round#set_computer_move Set in a before_save callback I get the randomized computers move. Nice, I like this new Ruby 1.9.2+ Random class. Hadn’t seen that one yet. Still never really trust computer “random” though… Of course this method could be extended to handle machine learning as we’re storing a history of user moves.

Round#result The “core business logic” :) of the app returning whether the round was :won, :lost or :tied from the perspective of the user I paused for a bit wondering if I should normalize or embellish here further, but honestly my highest order of business generally in Ruby is to maintain explicit and readable code more than be sly.

Round#won?, Round#lost? These helper methods were added later as I developed the Views and wanted things to be a little clearer.

3) Controller / Session: Plumbing

<edit app/controllers/rounds_controller.rb> RoundsController#index, RoundsController#create, RoundsController#destroy Not much to say here. The basic fitting to a resource. If I Ajax’ified things I’d have a couple more actions (“new”, for instance).

<edit app/controllers/application_controller.rb> This init_session before_filter in the ApplicationController#init_session before_filter was necessary due to an issue (?) with Rails instantiating a session on the initial request if some value is not set in the session hash.

4) View layers: Make it fun and pretty

<create app/views/rounds/index.html.haml> <edit app/assets/javascripts/applications.js> <edit app/assets/stylesheets/applications.css.scss> <add app/assets/images/*>

I tried a few versions of the view before settling. Based on how I set things up there was more space to play on the front-end of things here than back-end. I went over the allocated 2 hrs a bit and this playing was the reason for it. I confess, at one point I had implemented 3d CSS cubes to present the rounds, thought it’d be cute to have “3d Jankenpo!” but that was too cute and so I ripped them out.

…grabbed images from Wikipedia and a Google Image Search to find a passable “computer” hand (just didn’t feel right to have the computer play with a fleshy hand).

<edit app/controllers/rounds_controller.rb> In general I changed things in here a few times as I wrapped-up / tidyed the view.

5) Wrap-up / self-grading:

I’ve been pretty deep into a re-factoring of a large application for months over here and kinda needed something to play with for a night. That is my excuse for having given this app more like 4 hrs than 1-2 hrs as instructed.

Also, I’ve importantly drifted from the instruction to Git commit frequently explaining myself as I went in real-time. I liked that plan, I understood the intention and appreciated it: to get a sense for how I approach a problem and it’s implementation. I hope this narrative in addition to the incremental set of commits I am making helps to clear things up.

I’ve written no Tests or Specs. That just felt too much, too academic for the purpose of this exercise.