Another tour of Scala


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I find the tour of scala a nice idea, but very difficult to follow for a few reasons:

  • The level of the tour elements skips from extremely basic to beyond advanced without a good guide through. This has left me scratching my head at some of the more advanced concepts.
  • Many of the features are demonstrated via mathematical conecpts or completely arbitrary calculations (how often do I need to take a list and arbitrarily modulo its contents into a new list?)
  • Some features are demonstrated by setting up a convoluted problem that the feature magically solves, leaving me wondering why the feature even exists, when a simpler design for the problem at hand would have obviated the need for it.
  • The more advanced topics are described in very terse format and difficult to understand without what I assume is a deep understanding of Scala already or some other functional programming language.

So, I’m going through each thing and trying to:

  • Order them sensibly, so previous topics support future ones
  • Create more real-world situations where a feature might be useful (I make you this promise: The word “monoid” will never be used again in these pages)
  • Comment on my own thoughts as to the utility of the feature.

I’m also a Java programmer by trade, so a lot of the “justification” aspects that come to me are in comparison to Java.

The Tour


  • UnifiedTypes
  • ScalaBasics
  • ScalaClasses
  • ScalaPackages
  • ScalaTraits
  • ScalaGenerics
  • ScalaAnnotations
  • ScalaOperators


  • ScalaFunctions
  • PatternMatching
  • FunctionCurrying – define a function that has received some of its parameters now, and will get the remainder later.
  • CaseClasses – taking switch statements to a useful level.
  • SealedClasses – tightening up CaseClasses.
  • XmlLiterals
  • ForComprehensions – don’t let the name confuse you; this is about Scala’s powerful for loop construct
  • TypeBounds
  • InnerClasses – you only thought they were basic.
  • ImplicitConversions
  • TypeDependentClosures – Closures in general discussed here, too.


  • TypeVariance
  • AbstractTypes – not abstract classes
  • ExplcitlyTypedSelfReferences


I haven’t looked at this and they are not all covered by the above (though some may be)

  • ImplicitParameters
  • HigherOrderFunctions
  • ExtractorObjects

Last Updated 07/27/2009 at 11:56:46 AM by davec

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