Object Mentor Blog: More Clojure from Uncle Bob JSPS

More Clojure from Uncle Bob JSPS

Uncle Bob — Fri, 31 Jul 2009 08:12:44 -0500

Thanks to all who posted their solutions to the Bowling Game. Just to be contrary, I decided to implement yet another kind of solution. This one clearly shows my OO roots.

h2. Here are the tests.

(ns bowling-game)
(use 'clojure.contrib.test-is)
(use 'bowling-game)

(defn roll-list [game list]
  (vec (concat game list)))

(defn roll-many [game n pins]
  (roll-list game (repeat n pins)))

(deftest can-create-game
  (is (not (nil? (new-game)))))

(deftest gutter-game-should-score-0
  (is (= 0 (score (-> (new-game) (roll-many 20 0))))))

(deftest all-ones-should-score-20
  (is (= 20 (score (-> (new-game) (roll-many 20 1))))))

(deftest one-spare
  (is (= 16 (score (-> (new-game) (roll-list [5 5 3]) (roll-many 17 0))))))

(deftest one_strike
  (is (= 24 (score (-> (new-game) (roll-list [10 3 4]) (roll-many 16 0))))))

(deftest perfect-game
  (is (= 300 (score (-> (new-game) (roll-many 12 10))))))

(run-tests 'bowling-game)

And here is the code.

(ns bowling-game)
(defn new-game [] [])

(defn frame-type [[first second]]
  (cond
    (= 10 first) :strike
    (= 10 (+ first second)) :spare
    :else :no-mark))

(defmulti frame-size frame-type)
(defmethod frame-size :strike [_] 1)
(defmethod frame-size :spare [_] 2)
(defmethod frame-size :no-mark [_] 2)

(defmulti frame-score frame-type)
(defmethod frame-score :strike [[_ first second]] (+ 10 (+ first second)))
(defmethod frame-score :spare [[_ _ next]] (+ 10 next))
(defmethod frame-score :no-mark [[first second]] (+ first second))

(defn score [game]
  (loop [frame 1 rolls game score 0]
    (if (> frame 10)
      score
      (recur (inc frame) (subvec rolls (frame-size rolls)) (+ score (frame-score rolls))))))

"More Clojure from Uncle Bob JSPS" by Discount Louboutin Shoes

Wed, 11 Jan 2012 20:31:09 -0600

Every women always has Christian Louboutins Wedding Shoes turn of fame but it also has its own goodbyes.

"More Clojure from Uncle Bob JSPS" by gianmarco lorenzi

Sun, 01 Jan 2012 21:03:59 -0600

too wide to freeze

"More Clojure from Uncle Bob JSPS" by Tips For Bowling

Tue, 18 Oct 2011 12:19:59 -0500

Everybody has a high point and a lot goes into that: timing, situation, general consciousness.

"More Clojure from Uncle Bob JSPS" by best sleep aid

Fri, 30 Sep 2011 12:26:08 -0500

Cloudsourcing combines on-demand business process outsourcing (BPO) with crowdsourcing technologies to enable companies to purchase quality BPO services on-demand through a pay-per-use model.

"More Clojure from Uncle Bob JSPS" by bagsupplyer

Tue, 06 Sep 2011 04:02:02 -0500

Thanks for share with us.I look forward to reading more. Designer fashion women replica shoulder bag from China for sale on line

"More Clojure from Uncle Bob JSPS" by beats by dr dre headphones

Fri, 03 Jun 2011 23:09:00 -0500

I found that his foot odors never bring us to death.I never regret buying these beats by dr dre studio for him. These beats by dr dre solo are just the same as selling in the franchise store.Or even better.

"More Clojure from Uncle Bob JSPS" by shoes christian louboutin

Wed, 18 May 2011 23:02:32 -0500

It doesn’t matter, I can upload again for you. What server do you prefer most? :D

"More Clojure from Uncle Bob JSPS" by okey oyunu oyna

Thu, 28 Apr 2011 14:48:37 -0500

Nice code. Thanks

internette görüntülü olarak okey oyunu oyna, gerçek kisilerle tanis, turnuva heyecanini yasa.

"More Clojure from Uncle Bob JSPS" by vibradngers

Sat, 19 Mar 2011 04:29:01 -0500

I started with making enhancements to a unit test framework called lisp-unit. What I wanted is to change its output and also to add fixtures to my tests.

"More Clojure from Uncle Bob JSPS" by cold room

Mon, 28 Feb 2011 23:45:49 -0600

Haile Electric Industrial Co. Ltd. is the leading manufacturer and exporter of cold room,axial fan,condensing unit,centrifugal fan,shaded pole motor and refrigeration products in China.

"More Clojure from Uncle Bob JSPS" by Criminal Records

Thu, 17 Feb 2011 16:45:34 -0600

I started with making enhancements to a unit test framework called lisp-unit. What I wanted is to change its output and also to add fixtures to my tests.

"More Clojure from Uncle Bob JSPS" by Tenant Screening

Thu, 17 Feb 2011 14:44:30 -0600

I understand why it is, but still the nice thing about using a lisp language is that you can change it to go in the direction of a DSL. Unit testing is an DSL.

"More Clojure from Uncle Bob JSPS" by lupus symptoms

Sun, 06 Feb 2011 07:50:15 -0600

I guess that I’ll persevere with it, especially since you lately tweeted that your opinion of the book is changing, that the organization is frustrating, but the content is rich.

"More Clojure from Uncle Bob JSPS" by Criminal Check

Tue, 11 Jan 2011 13:04:10 -0600

The most important part of OOP is data encapsulation and having the methods that transform the data into the behavior that the object needs and the above definitely qualifies.

"More Clojure from Uncle Bob JSPS" by garbage bag making machine

Mon, 10 Jan 2011 00:17:42 -0600

This is one of the most professional manufacturers and suppliers in plastic packing machinery. We mainly provide non woven bag making machine,disposable glove machines,blowing film machines,flexo printing machines,garbage bag making machine etc.

"More Clojure from Uncle Bob JSPS" by moncler

Thu, 06 Jan 2011 09:05:36 -0600

thanks for Moncler Jackets || Christian louboutin UK || Moncler coats || Christian louboutin shoes || Christian louboutin pumps your post!

"More Clojure from Uncle Bob JSPS" by Silicone Molding

Mon, 03 Jan 2011 20:55:43 -0600

Mold making is the core business of Intertech (Taiwan). With world level technology, Intertech enjoys a very good reputation for making Injection Mold and Plastic Moldsfor their worldwide customers.

"More Clojure from Uncle Bob JSPS" by willson

Fri, 10 Dec 2010 01:29:43 -0600

Thanks for sharing. I get satisfaction from this site. preserve it up. uggs outlet

"More Clojure from Uncle Bob JSPS" by Mens Watch

Tue, 26 Oct 2010 03:35:16 -0500

Lady Gaga Mens Watch has undergone louis vuitton wallet a “spiritual” commitment ceremony with her boyfriend.The rolex watch ‘Paparazzi’hitmaker and Luc Carl reportedly .zf

"More Clojure from Uncle Bob JSPS" by bag manufacturer

Sun, 12 Sep 2010 22:27:54 -0500

tions to the Bowling Game. Just to be contrary, I decided to implement ye

"More Clojure from Uncle Bob JSPS" by Bob

Sat, 14 Aug 2010 01:34:39 -0500

Really helpful for me.I have learned a lot makeup brushes about asp.net from this.

"More Clojure from Uncle Bob JSPS" by Kooba Handbags

Wed, 31 Mar 2010 23:05:04 -0500

Living without an aim is like sailing without a compass. with a new http://www.handbags4buy.com/ idea is a crank until the idea succeeds.

"More Clojure from Uncle Bob JSPS" by Philip Schwarz

Sat, 01 Aug 2009 20:50:18 -0500

@Uncle Bob

When I saw your previous blog entry, Uncle Bob, JSPS: Learning Clojure, I had a go at coding the bowling game, but didn’t get round to posting my solution because I got interrupted by something else.

I had gone for exactly the same frame-type function as you did! Here is my attempt (my first Clojure program):

(defn frame-type [[first second]] 
    (cond (= 10 first) :strike
          (= 10 (+ first second)) :spare
          :else :normal))

(defmulti score frame-type)
(defmethod score :strike [[_ first second & rest]] 
  (+ 10 first second (if (nil? rest) 0 (score (into [first second] rest)))))
(defmethod score :spare  [[_ _ next & rest]] 
  (+ 10 next (if (nil? rest) 0 (score (cons next rest)))))
(defmethod score :normal [[first second & rest]] 
  (+ first second (if (nil? rest) 0 (score rest))))

At the time, I did not write it test-first, but I have now tested it using a minor adaptation of your tests:

(deftest gutter-game-should-score-0
  (is (= 0 (score  (repeat 20 0)))))  
(deftest all-ones-should-score-20
  (is (= 20 (score  (repeat 20 1)))))
(deftest one-spare
  (is (= 16 (score (into [5 5 3] (repeat 17 0) ) )))) 
(deftest one-strike
  (is (= 24 (score (into [10 3 4] (repeat 16 0))))))  
(deftest perfect-game
  (is (= 300 (score (repeat 12 10)))))
(run-tests)

I prefer my Haskell version of the Bowling Game:

score [x, y]                             = x + y      -- Normal Frame
score [10, x, y]                         = 10 + x + y -- Strike
score [x, y, z]                          = 10 + z     -- Spare
score (10:(x:(y:rest)))                  = 10 + x + y + score (x:(y:rest)) -- Strike
score (x:(y:(z:rest)))  | (x + y) == 10  = 10 + z + score (z:rest)         -- Spare
score (x:(y:rest))      | otherwise      = x + y + score rest              -- Normal Frame

It is easier to read/understand.

Your initial tweet about the Clojure book prompted me to get a copy of the book. I agree with your later tweet, that the book is disappointing because it feels rushed, but I guess that I’ll persevere with it, especially since you lately tweeted that your opinion of the book is changing, that the organization is frustrating, but the content is rich.

I look forward to your future thoughts on functional programming.

"More Clojure from Uncle Bob JSPS" by http://uglylispcode.wordpress.com

Sat, 01 Aug 2009 19:46:11 -0500

@uncle bob,

If any yahoos try telling you that functional programming is not OOP, they are blowing smoke.

A lambda over let over lambda is an object.

To me the most important part of OOP is data encapsulation and having the methods that transform the data into the behavior that the object needs and the above definitely qualifies.

You don’t think that the principles that you use for OOP no longer apply when working with a functional program? OCP, SRP, LSP, and all the rest definitely apply.

If you keep in mind that sequences (alist and plist) is the basic data types. And that the operators (I say operators not methods) are used to transform (iteration and recursion) the lists into the outputs you desire.

When I started working with CL, I started with making enhancements to a unit test framework called lisp-unit. What I wanted is to change its output and also to add fixtures to my tests.

For me the unit test framework is ugly: (is(= 0 0)) what the hell! The first thing I would do is change it something like this: (should= 0, 0) or (is= 0, 0). The parenthesis has too much noise. I understand why it is, but still the nice thing about using a lisp language is that you can change it to go in the direction of a DSL. Unit testing is an DSL.

I highly recommend that when starting a new language use it with something that you do know

Right now I’ve stopped with the CL and am back into the dotnet world. I want to bring some of the things I learned with CL back into C#.

My two blogs are here, check them out: http://uglylispcode.wordpress.com http://uglycode.wordpress.com