Getting Started with Scala

• Functional Programming
  • Mars Rover
    • Instructions to follow
      • turn left
      • turn right
      • move without changing direction
    • Find position after series of commands
      • like: MMRMMRMRRM
  • + - Parking Lot Attendant
    • Directs cars to appropriate lots
    • Uses lot selection strategies
      • First available
      • Most capacity
      • Most Free
      • Cheapest
• + - Domain Specific Languages
  • Enablers
    • Call by name parameters
      • Implement while loop
    • Structural typing
      • Duck typing with type safety
    • Implicits
      • Scoped open classes
  • Internal
    • ScalaTest
      • Unified DSL for incosistent API
      • Example
        • string should have length (7)
          array should have length (7)
          document should have length (7)
          
  • External
    • Combinator parsing
      • Use Internal DSL to create external DSL
      • Pattern matching
      • + - Google code jam 2009 - Round1B - Problem A
        • http://code.google.com/codejam/contest/dashboard?c=186264#
        • Grammer

          • tree ::= (weight [feature tree tree])
            weight is a real number between 0 and 1, inclusive
            feature is a string of 1 or more lower case English letters

        • Example

          • (0.2 furry
             (0.81 fast
               (0.3)
               (0.2)
             )
             (0.1 fishy
               (0.3 freshwater
                 (0.01)
                 (0.01)
               )
               (0.1)
             )
            )

• + - OOP
  • Improvements
    • Everything is object
    • No statics
    • Type inference
    • Unified operators and methods
    • Path dependant types
  • Traits
    • Minimal AOP example
      • Multiple queue implementations
      • Multiple stackable modifications
      • On the fly combinations
  • Abstract Types
    • Quantities
      • Contrast with parameterized version
• + - More
  • Functional programming
    • Monads
    • Design site generics
      • variance annotations
  • DSL
    • Actors
    • Enumeration
  • OOP
    • DI
    • Self types
    • Java interoperability
      • ICFP-solution