On Exploratory Design and Piecemeal Development

I have a soft spot for Lisp-like languages, I suspect I always will. I've now been programming in Scala for several months. And I sometimes find the language tedious. I've lately been thinking about , , and other such essays in relation to how I feel about Scala vs Lisp.



Let's take a look at what Scala offers:

Where have I been for the last year?

I'm hoping to keep this relatively short, I don't think I'll succeed.A year ago, my parents and I got in the car. Our destination, London Stansted airport, the reason, I was going digging in the Czech Republic. How do I remember, it was the same weekend as the UK grand prix. Now with the grand prix occurring at Silverstone again, it brings back those memories of what I've done, where I've been, who I've met and the distance covered.Czech Republic, Bulgaria, Spain, Portugal, Morocco. I've met people from every single inhabited continent, from an exhaustive range of countries. I've seen incredible sights, experienced highs and lows, spoken up to eight different languages (Only three proficiently), and the highlight of it all, has been Granada, may it carry on for another millennium as it is. To me, it is perfect. So on today, the day I started this adventure I'm on, it seems ironically apt that once again I am travelling.Sadly, this year ahead might just be a bit more dull. Final year, a dissertation and graduation. Let's try to live it up whilst we can now right? - Full Post

Scalability: Links, News And Resources (4)

Scaling with MongoDB
Big Data @ Foursquare: Slides from our recent talk
Fun with MongoDB replica sets
Scaling Rails
Voldemort is a distributed key-value storage system
USING HAPROXY FOR MYSQL FAILOVER AND REDUNDANCY
Amazon’s Dynamo
Sharding & IDs at Instagram
HAProxy
The Reliable, High Performance TCP/HTTP Load Balancer
Ken Little on Scaling Tumblr
Ken Little talks about scaling Tumblr to keep up with their blogging users: scaling the data model, sharding, their PHP frontend and the Scala backend, and much more.
The 4 Building Blocks Of Architecting Systems For Scale
nsisodiya / Demo-Scalable-App
This is small demo of Scalable JavaScript Application
Scaling to Millions of Simultaneous Connections: Rick Reed
Drill
Drill is a distributed system for interactive analysis of large-scale datasets, inspired by Google’s Dremel.
NuoDB
An Easy Way to Build Scalable Network Programs
Memcached
Redis Virtual Memory: the story and the code
Improving Web Site Performance and Scalability While Saving Money
Scalable JavaScript Design Patterns
Cinchcast Architecture – Producing 1,500 Hours Of Audio Every Day
The Netflix Simian Army
C Is For Compute – Google Compute Engine (GCE)
My Links
Keep tuned!
Angel “Java” Lopez
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TDD Kata (5): Tree Search

Some months ago, I read this message in a TDD list:
Implementation of game tree search using TDD
I read:
I am trying to use TDD to implement game tree searching but I am running into some issues.Using C#, MS Test and Rhino Mocks. My requirement is to traverse a tree to a specified depth and find the maximum value of the nodes at this depth. If a path ends before the specified depth then the value of the last node in the path should be considered. Sample usage looks like this: var depth = 5; var tree = new GameTree(); var treeSearch = new TreeSearch();var maxValue = treeSearch.FindMaxValue(tree, depth);

The first tests to implement:
* A search to depth zero should return the value of the root node * A search to depth one with no children should return the value of the root node * A search to depth one with one child should return the value of the child * A search to depth one with two children should return the highest value of the two children * A search to depth one of a tree with depth two should return the maximum value at depth one

All right, but:
Up to this point the tests are simple enough and mocking of the tree is simple. The last test starts driving towards a depth first tree traversal.Now I start on depth 2 tests which should drive the rest of the tree traversal algorithm: * A search to depth two should return the maximum value at depth two I decided to mock a complete binary tree with depth 2

The problem is the use of mocks: it complicates the solution. So, I started to solve the problem, without mocks, simply using a tree implementation to use as a base for other tests:

The solution is simple:

You can see the history of development at:

All tests are green:

Lesson learnt: some times (many times is easier to implement something concrete than build a mock. The tree I implemented could be refined, could be the base for an interface extraction, or could be implemented in other ways. But it served as a base for our search algorithm, using TDD.
Keep tuned!
Angel “Java” Lopez
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I'm Not Calling You A Liar

I've gone on record as saying that I have wonderful friends, truly wonderful friends.  I love my friends - my close friends - as much as I love my family.  I generally go to them for all kinds of advice and also when I simply want to have a good time with someone I like.There is, however one thing about my friends that I hate.  When friends tell me (in regards to relationships) that I am "a great guy... - Full Post

Running and Reading

The last week or so has been one of the more frustrating and interesting of my life.  On the positive side, I ran 6 miles the other day and felt great afterwards; no cramps, no serious burn (if you run, legitimately run, there's going to be burn) and my chest felt great, no breathing issues.  I think I am really starting to get a more healthy cardiovascular system developed; it only took 2 and a half years or so but it happened finally.  The kind of annoying news is that I have not slept (as of this posting) in 40 hours.  At about 6am this morning I decided that I had officially reached the point where I needed to wither be up or go to bed all day; I opted to get up.  I ran about the most pleasant four miles of my life; it was humid and cool, the campus was vacant (as it should be at 6am on a Sunday) and I had plenty of time to run and be alone with my thoughts.  Another bit of good information is that I finally got some thesis stuff done; I met with the research librarian here on campus who gave me a couple of great databases and research programs that I know are going to be really helpful.  I have not yet received a stipend check (first one is June 1st I think) but I have not to do anything I would have to pay for... - Full Post

The GRE is Laaaame

The Sentence Equivalence questions on the GRE are asinine.  They aren't asking you to relate two words together or chose the two words that most closely are synonymous; they are asking you to choose from (what essentially is) 3 pairs of synonyms and decide which pair fits best and best is arbitrary because it depends on what meaning they want the sentence to have; all 3 word pairings make complete sense but if it is not the one ETS likes the most, thinks is the shiniest and prettiest, then it is not right.  I hate this country's obsession with standardized tests. That is all. - Full Post