Scala Logging

Scala Logging

http://scala-programming-language.1934581.n4.nabble.com/verbose-logger-usage-td3084112.html

AOP:
<http://jonasboner.com/2008/02/06/aop-style-mixin-composition-stacks-in-scala.html>
<http://jonasboner.com/2008/10/06/real-world-scala-dependency-injection-di.html>
<http://jonasboner.com/2008/12/09/real-world-scala-managing-cross-cutting-concerns-using-mixin-composition-and-aop/> 

Pointfree

http://www.haskell.org/haskellwiki/Pointfree

it is clearer to write

let fn = f . g . h

than to write

let fn x = f (g (h x))

The term originated in topology, a branch of mathematics which works with spaces composed of points, and functions between those spaces. So a 'points-free' definition of a function is one which does not explicitly mention the points (values) of the space on which the function acts. In Haskell, our 'space' is some type, and 'points' are values.

Pros
This style is particularly useful when deriving efficient programs by calculation and, in general, constitutes good discipline. It helps the writer (and reader) think about composing functions (high level), rather than shuffling data (low level).
It is a common experience when rewriting expressions in pointfree style to derive more compact, clearer versions of the code -- explicit points often obscure the underlying algorithm.


Cons
Point-free style can (clearly) lead to Obfuscation when used unwisely. As higher-order functions are chained together, it can become harder to mentally infer the types of expressions. The mental cues to an expression's type (explicit function arguments, and the number of arguments) go missing.
Point-free style often times leads to code which is difficult to modify. A function written in a pointfree style may have to be radically changed to make minor changes in functionality. This is because the function becomes more complicated than a composition of lambdas and other functions, and compositions must be changed to application for a pointful function.
Perhaps these are why pointfree style is sometimes (often?) referred to as pointless style.

eta conversion

http://www.haskell.org/haskellwiki/Eta_expansion

eta conversion (also written η-conversion) is adding or dropping of abstraction over a function. For
example, the following two values are equivalent under η-conversion:

\x -> abs x

and

abs

Converting from the first to the second would constitute an eta reduction, and moving from the second to the first would be an eta abstraction. 

progopedia

Encyclopedia of Programming Languages
http://progopedia.com/

Yoxos5 Share Eclipse Configuration

http://eclipsesource.com/en/yoxos/

Language Classifications

Strict (call-by-value)
Lazy (call-by-need)
Pure
Static
Dynamic
Duck-typed
Functional
Object-oriented

Language	Pure	Strict	Non-Strict (Lazy)
Haskell	Yes	No	Yes
ML
Erlang
Scheme
Java
C#
Scala
Ruby
F#
SQL
Regex

OCaml notes

Functional core of Objective CAML:

http://caml.inria.fr/pub/docs/oreilly-book/html/book-ora015.html

Variables are variable:

# let p = 10 ;;
val p : int = 10
# let k x = (x, p, x+p) ;;
val k : int -> int * int * int = 
# k p ;;
- : int * int * int = 10, 10, 20
# let p = 1000 ;;
val p : int = 1000
# k p ;;
- : int * int * int = 1000, 10, 1010

http://caml.inria.fr/pub/docs/manual-ocaml/expr.html

Looping:

while expr1 do  expr2 done

for name =  expr1 to  expr2 do  expr3 done

for name =  expr1 downto  expr2 do  expr3 done 

Exceptions: try ... with ... -> ...

Objects

Coercion (casting to superclass): subobject :> superclass

Message sending (calling method on object): object # method

Object duplication: Oo.copy

Recursive functions: rec

String concatenation: ^

Characters delimited by ` not ': `a`

http://caml.inria.fr/pub/docs/oreilly-book/html/book-ora016.html#toc21 

Tuples

Records

Sum Types

Constant Constructor: type suit = Spades | Hearts | Diamonds | Clubs ;; 

  Constructor with Args: type card = King of suit | Queen of suit | Knight of suit | Knave of suit | Minor_card of suit * int | Trump of int | Joker ;;

Recursive Types

Parameterised Types: type ('a, 'b) list2 =

Hindley-Milner Type Inference

http://www.codecommit.com/blog/scala/what-is-hindley-milner-and-why-is-it-cool

http://dysphoria.net/2009/06/28/hindley-milner-type-inference-in-scala/

Scala not a functional programming language

http://enfranchisedmind.com/blog/posts/scala-not-functional/

Scala foldLeft and map

Scala foldLeft and map

http://stackoverflow.com/questions/2293592/functional-programming-scala-map-and-fold-left

Emulating structural pattern matching over algebraic data types in Java

http://apocalisp.wordpress.com/2009/08/21/structural-pattern-matching-in-java/

http://apocalisp.wordpress.com/category/programming/java/

FizzBuzz links

Scala: http://www.virtuousprogrammer.com/?p=153

http://en.wikipedia.org/wiki/Bizz_buzz

Yow Night - Cloud

Cloud
8/6/2011

Tim Buntel – MS SQL Azure
www.windowsazurepass.com
Promocode: Azurecloud

Clayton Brown – SalesForce
IaaS, PaaS, Saas

Hardy – Ninefold
Iaas
5 key concerns
• Latency
• Self-service
• Data jurisdiction
• Solid financial backing
• Local support
XenServer or VMWare
CentOS, Open SUSE, Ubuntu, Windows 2003/08
Upload ISO
Don’t pay if don’t use
Starts from 2.2c/hr ($30/m) 1 CPU, 384Mb RAM, 80Gb HDD


James Durell – SpringSource Cloud Foundry
Open PaaS
github.com/cloudfoundry


Security?
Risk?
Insurance?
DR?

Yow night – 12 Agile Adoption Failure Modes

Jean Tabaka

9/6/2011

Rally: Tim Miller, Ryan Martins

pm.stackexchange.com

Most orgs have suicidal tendencies

It’s about caring for your world

David Snowden sense making – failure stories are most powerful

Agile helps me be a better me/artist – create your own reality

1. Checkbook commitment
1. Unengaged – just do it
2. Culture that doesn’t support change
1. “Follow the plan”
2. Need to change the metrics
3. Best practices… good practices… emergent practices
4. Standard of work enforced

                                                               i.      Governance = conformance

                                                             ii.      Standard of work is static

                                                            iii.      Cross-org uniform

                                                           iv.      Detailed documentation security blanket

                                                             v.      PMO as enforcers

3. Ineffective use of retrospectives
1. “This sucks” threshold  – if nothing’s gonna change, why bother?
2. Should ask:

                                                               i.      What are we doing well?

                                                             ii.      What’s not serving us as a team?

                                                            iii.      What would we change to improve?

3. No retrospective
4. There is absolutely nothing wrong
5. No action
3. Stable environment?
4. TANSTAAFL – There ain’t no such thing as a free lunch
1. Will work for infrastructure
5. Lack of full planning participation
1. Waiting for decisions = waste
2. Conversation
3. Unavailable product owner
4. Too many product owners
5. Too busy for all the communicating
6. Product owner = hardest role. What does product owner get out of it?
7. Commitment with team
6. Bad scrum masters
1. Command and control

                                                               i.      Telling people what to do = Low morale and lower IQs

                                                             ii.      Cognitive abilities approve the more decisions we make

2. Servant Leader

                                                               i.      Serve and facilitate

                                                             ii.      Remove impediments

8. Not having an onsite evangelist
9. Team lacking
1. Red tape decisions
2. Not forming, storming, norming, performing
10. Testing not pulled forward
1. Pushed to deliver
2. Increased defects
3. Failure-demand work vs value-demand work
4. Piled up trash
5. Stop the line
11. Traditional performance appraisals
1. Manager’s yearly evaluation
2. Individual heroics rewarded – holds back agile success
3. Frequent team evaluation
12. Reverting to form
1. Change is hard

“Drive” Daniel Pink

Monads for Java Programmer

http://irekjozwiak.com/entry/2009/06/13/Monads-for-Java-C---programmers.html

(>>=) bind

a1 >>= a2 = join (fmap a2 a1)

fmap _            Nothing       = Nothing

fmap someFunction (Just a)      = Just (someFunction a)
 

> fmap (+ 2) (Just 4)
Just 6

> fmap (+ 2) (Nothing)
Nothing

join Nothing         = Nothing
join (Just Nothing)  = Nothing
join (Just (Just x)) = Just x