Koans, Katas, Oh my by Cory Foy
Practice outside production is essential
Write dreyfus number 1-5 on head of others in conversation
Shu Ha Ri
Koans is a mindset, the actual excercises are katas.
Katas: You know solution, practice solving them
Code Kata origin: Dave Thomas
Katacasts
KataFizzBuzz
http://codingdojo.org/cgi-bin/wiki.pl?KataFizzBuzz
TDD as you meant it (gojko.net)
Only refactor out production code
Code retreat - C0d3r3tr3at
Game Of Life
How do we try out stuff otherwise? We introduce in in our production code! Is that good?
Cory Haynes – Has done a lot of Javascript testing lately.
Scala Thinking by Ted Neward
Functional
- Order Does Not Matter à No notion of sequence like
· i=1;
· i =i+2;
- There is no shared state à always same return from function – no side effects.
- But: Sometimes order matter (fly before explodes)
- Scala says: There’s goodness in both functional and OO world.
What the outcome of combo of F and OO is not yet known, nobody knows!
Scala is impure FL, allows
- functions as first-class values
- strongly typed, type-inferenced
- immutable values
- expressions-not-statements
- typles, lists
- recursion
- pattern-matching
- currying, partial-application of functions
lambda calculus
f(x,y) = x + y
f(x,y,op) = x (op) y
add (x, y) = x + y
inc = add 1 (returns first class value function that takes one value)
Function that takes more than 2 parameters are too long – compare to Bob J
Currying à Pipelining
Val convertToInt = { x:String => x.toInt }
Val doubleIt = { x:Int => x * 2 }
Val sqrtIt = { x:Double => Mat.sqrt(x) }
Val pipeline = convertToInt andThen doubleIt andThen int2double andThen sqrtIt
RUN:
Scalac person.scala
Javap Person (Shows java-code)
object App {
Unit testing? Yepp, but maybe Java TDD? Make unit testing first compile scala? Would be cool to integrate!
Using from Java?
Problems
lift framework
Tomorrow: Go to Java Bytecode!!!
Anything is better than java.
Why use scala: Unless you want to write tomorrows legacy code today.
