A self-type for a trait A: trait B trait A { this: B => } says that “A cannot be mixed into a concrete class that does not also extend B“. On the other hand, the following: trait B trait A extends B says that “any (concrete or abstract) class mixing in A will also … Read more
An implicit question to newcomers to Scala seems to be: where does the compiler look for implicits? I mean implicit because the question never seems to get fully formed, as if there weren’t words for it. 🙂 For example, where do the values for integral below come from? scala> import scala.math._ import scala.math._ scala> def … Read more
Scala syntax has a lot of symbols. Since these kinds of names are difficult to find using search engines, a comprehensive list of them would be helpful. What are all of the symbols in Scala, and what does each of them do? In particular, I’d like to know about ->, ||=, ++=, <=, _._, ::, … Read more
If I have an EnumeratorT and a corresponding IterateeT I can run them together: val en: EnumeratorT[String, Task] = EnumeratorT.enumList(List(“a”, “b”, “c”)) val it: IterateeT[String, Task, Int] = IterateeT.length (it &= en).run : Task[Int] If the enumerator monad is “bigger” than the iteratee monad, I can use up or, more generally, Hoist to “lift” the … Read more
I searched in Google to find the differences between a case class and a class. Everyone mentions that when you want to do pattern matching on the class, use case class. Otherwise use classes and also mentioning some extra perks like equals and hash code overriding. But are these the only reasons why one should … Read more
I’ve taken a look at the list of surveys taken on scala-lang.org and noticed a curious question: “Can you name all the uses of “_”?”. Can you? If yes, please do so here. Explanatory examples are appreciated. 7 s 7
Closed. This question needs to be more focused. It is not currently accepting answers. Closed 8 years ago. Locked. This question and its answers are locked because the question is off-topic but has historical significance. It is not currently accepting new answers or interactions. Can someone please explain the major differences between Scala, Groovy and … Read more
I’m just going over some Scala tutorials on the Internet and have noticed in some examples an object is declared at the start of the example. What is the difference between class and object in Scala? 13 s 13 tl;dr class C defines a class, just as in Java or C++. object O creates a … Read more
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