I have found that the issue isn't the language, it's the ecosystem. If you're coming from Java environment set up is not such a big deal, but if your brand new it is not as easy as other languages.
There are certainly poor libraries and bad advice going around (why people tell beginners to use SBT or ScalaTest is beyond me), but that happens in every language. IME the average quality on maven central is if anything better than on PyPi/rubygems/npm/etc., and the IDEs/profilers/debuggers are better than anything you can get for the other languages.
I can think of some very good reasons to suggest SBT to beginners. Probably the most useful features, in this regard, is that a folder with some Scala files in it is a valid SBT project. You don't even need a build configuration file. This is substantially less work than setting up a Scala project through Gradle, Maven, Ant or an IDE.
Also, if you use SBT through Activator[1] you get project templates and an automatically configured IDE.
> I can think of some very good reasons to suggest SBT to beginners. Probably the most useful features, in this regard, is that a folder with some Scala files in it is a valid SBT project. You don't even need a build configuration file.
Sounds horribly magic/incomprehensible.
> This is substantially less work than setting up a Scala project through Gradle, Maven, Ant or an IDE.
I don't think the work of doing it in Maven with an IDE could be called substantial. Push the button, choose the scala template, give it a groupId and artifactId, done.
Maven and Ant are barely maintained anymore despite so many broken things. Just compare artifact resolution/download speed between Maven/Ivy and sbt with coursier.
There is no way in hell I'll ever touch Maven again. SBT works without a single line of configuration, and that IDEs are not able to touch config files is a big fat benefit.
Eclipse developers can't even turn it into a working editor. I certainly don't want Eclipse to deal with my project configuration.
I'll get over my hate when every setting is documented, every operator is documented in a searchable way (which probably means replacing most of them or writing their own search engine), and build definitions are no longer turing-complete. Until then, Maven's a much better option.
How is compiling everything in a given directory any more magic/incomprehensible than any other build tool?
> I don't think the work of doing it in Maven with an IDE could be called substantial. Push the button, choose the scala template, give it a groupId and artifactId, done
What IDE comes with a 'scala template' out of the box? What if you are not already in the JVM ecosystem? With SBT, the set up is:
- Install SBT/Activator
With your suggested equivalent, the steps are:
- Install Maven
- Install IDE
- Install Scala IDE plugin
I think the SBT option sounds like they would be much less imposing for a beginner.
IntelliJ doesn't have the Scala plugin installed by default. However, that is true that you could combine the 'Install IDE' and the 'Install Scala IDE plugin' steps by installing the Scala IDE.
Even if you do combine those steps, there are still further steps a user would have take after they install everything. You described the set up as just being as simple as "Push the button, choose the scala template, give it a groupId and artifactId, done". However, I don't think it is that simple. As far as I'm aware, no IDE will give you a Scala project with a Maven POM. You can choose to create a 'Scala project' or you can create 'Maven project'. You can't create a 'Maven Scala project'. So you will have to figure out how to add Scala support to Maven manually. Also, you may have to figure out how to let your IDE know that your project is both a Maven project and Scala project.
I find it makes tests much less comprehensible (and gives them worse IDE integration) than JUnit; it uses gratuitous operator overloading style with e.g. "should". And for a beginner it doesn't really offer any advantage - if you're using generators or the like I can see it might be helpful, but for basic unit testing I find straightforward code with JUnit is much easier.
Using the natural language style assertions is optional though, and only work if you incorporate the 'Matchers' trait in your tests. If that's too magical, you can still use plain old assertions or one of the other styles here http://www.scalatest.org/user_guide/using_assertions
You can do what we did in my team: decide on a style of testing and stick to it (in our case, I liked WordSpec). With JUnit you can't do this, because there is only one style.
I particularly liked the "should", "must", "where", etc. DSL. If I remember correctly, this style of testing comes from the Rails community. I guess it's a matter of taste, but I would definitely recommend it to newbies.
I wouldn't recommend it to newbies at all, because it's using relatively advanced Scala features - implicit conversions to make the operators available, "word word word" style desugaring into method calls. Of course these are things that you have to learn eventually and that have value, but making a newbie learn how they work before they can test anything is throwing them in at the deep end, and having to use a test framework that you can't understand isn't good.
A lot of Java programmers don't understand how JUnit works, nor need to, and they still manage to use it, so I don't think this is a strong argument.
The point of DSLs is that they feel natural for their job, regardless of how they are implemented. You can use a DSL without understanding how it works "behind the scenes". To me, ScalaTest with WordSpec seems more natural than JUnit, and at least my own experience shows I'm right: I've successfully introduced it in a team of newbies.
> A lot of Java programmers don't understand how JUnit works, nor need to, and they still manage to use it, so I don't think this is a strong argument.
What's to understand? You write a method in plain old java, and the framework runs it.
> The point of DSLs is that they feel natural for their job, regardless of how they are implemented. You can use a DSL without understanding how it works "behind the scenes".
The point of "embedded DSLs" is that they follow the ordinary rules of the host language. Otherwise they're no better than an external config file, Cucumber-style (which some people apparently like, but I find utterly unusable).
> at least my own experience shows I'm right: I've successfully introduced it in a team of newbies.
When they make a change to code that breaks a test, and you're not there, how long does it take them to understand what's gone wrong? That's the real test of a test framework, and IME ScalaTest does very badly on it.
Let me ask your own question back at you: what's there to understand with WordSpec or Cucumber-style tests? It's just a tool, you just use it as documented... just like you don't need to even look at JUnit's implementation in order to use it.
Yes, when a WordSpec test starts failing, junior devs know how to fix it without my assistance. I haven't noticed any difference in dev effectiveness between ScalaTest and JUnit.
> Let me ask your own question back at you: what's there to understand with WordSpec or Cucumber-style tests?
To use Cucumber you have to understand a whole new grammar. To use ScalaTest you have to understand relatively obscure parts of Scala (implicit conversions, "word word word" style method calls, by-name parameters, ...) - or else treat it like a config file and learn a whole new grammar. To use JUnit you just write plain old Java/Scala.
I've found that Scala beginners google around, and come across lot's of blog posts extolling the virtues of Scalaz, implicits, using higher kinded types, embedding DSLs and so forth. All that is worthwhile, but not really accessible to beginners. It's understandable that Scala bloggers want to write about cutting-edge material, but this misleads beginners, who think you need to use Scalaz, monads and the like to be productive. Nothing could be further from the truth.
