But compare this to someone's experience with Python, Ruby, JavaScript, Go, or (maybe) Rust, where they are much more rapidly productive, and they actually have that immediate wow factor. I think this may also apply to "lighter"-weight Scala alternatives like Kotlin/Ceylon one day, depending on their adoption. So I think Scala pales on this dimension relative to its competition.
You can be just as productive as you would be in Python/Ruby/JavaScript/Go from day 1 in Scala - usually the same code will work, with minor syntax differences and maybe the occasional type annotation. The difference is there's more to learn in Scala that will make you even more productive, but that should never be a downside, and you don't have to learn it if you don't want to.
I have to agree with "lmm" and "the_af" here. You can use Scala as a "Java without semicolons", and indeed that's what I recommend to those who want to learn Scala coming form an OO background. There is absolutely no need to use fancy Scala features like higher-kinds or monadic effects. Indeed, there is no need even to use functional features. Scala is a perfectly fine OO language. The one thing I recommend to learn once a learner gets a grip on Scala syntax is pattern matching matching and case classes. It's really easy to understand. And once you understand it, you never want to go back.
I have had a substantial number of undergraduate students learn Scala this way for their final year project and they all got it pretty quickly.
You are advocating that beginners start using Scala without really understanding what they're doing, and being mostly unable to read other code or read the source, while writing what is considered to be bad Scala from the get go. Contrast this to languages like Python or Ruby, where it is totally possible to immediately start writing code you understand that follows the general gist of good Python/Ruby style.
You are certainly right that someone new to Scala can get started quickly this way. You are wrong that Scala is anywhere close to the same level on this dimension as Python or Ruby or Go.
No, I was talking about strong Java (or C# or C++) programmers learning Scala, starting with the OO part of Scala. Clearly this is not a large jump, as Scala has class-based OO that is really similar to Java, C# and C++. It is perfectly possible to be productive in this fragment.
I don't at all agree that someone can pick Python or Ruby up and start writing idiomatic (or even "good") code on day one. In fact I make a good living consulting in JRuby shops where they thought they would get some sort of benefit by using Rails but then wrote all the code as if they were still using Java.
I am speaking from direct personal experience. Explicit effect sequencing is optional (in contrast to Haskell), traditional OO with inheritance is available. You may not be able to read all the standard library type signatures on day 1 but the documentation is adequate without them. Anything you could do in Python/Ruby/Javascript translates directly; in the very short term I guess not having a single baked-into-the-language concurrency model like Go is a disadvantage, but the use case where you'd need that on day 1 is pretty rare.
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.
With a few exceptions, you can program in Scala as if it were Java++. You won't take full advantage of Scala, but it can be done, and beginners sometimes do precisely that.
It's a lot like learning SVN vs Git, SVN requires fewer steps to do a commit so you can be "productive" faster. Once you learn Git though you won't care that it took you a bit longer to learn. Prioritizing being productive immediately and instant gratification isn't always the best in the long term.
That's a pretty bad example. Git is widely considered [1] to be overly complex and difficult to learn compared to something like Mercurial. The advantage Git has is its dominance in terms of adoption/community. Scala does not have juggernaut dominance in programming languahes.
[1] I acknowledge this is debatable, but it's an opinion I agree with.
Not familiar with Go or Rust, but the issue with newcomers to Scala, as compared to Python, Ruby, Javascript is one of the ecosystem rather than the language. While that's very off-putting to newcomers, it hopefully is a one-time cost amortized of the life of your language use.
