we are considering Scala for a new Project within our company. We have some Junior Programmers with only PHP knowledge, and we are in doubt that they can handle Scala. What are your opinions? Some say: "Scala is a complicated beast!", some say: "It's easy once you got it." Maybe someone has real-world experience?
"My coworkers will not understand Scala" is simultaneously overstating its difficulty and insulting your coworkers.
Scala is not that difficult. It's just another programming language. Any trouble that junior programmers have with Scala is going to be more or less the same trouble they would have with any other language.
Your coworkers are smart. Of course, I don't know them, but it's a pretty safe bet unless your company is the kind of organisation that hires stupid people, in which case, you have bigger problems.
That said, at my company we have some core products developed in Scala, and we don't find that people have any more trouble with it than Java. The code is generally more clear and concise, easier to generalise and reuse, etc.
I guess Scala could be used as a "beginners" language. Even though there are tricky ideas behind it, you dont have to use/explain them in the beginning. If you explain pure OO with Scala, I would say it is straight forward and easily understandable. As Scala reduces a lot of code overhead from other languages it might even be easier to learn concepts with Scala than with Java/C++.
A major drawback I see with Scala as a beginner language is the lack of documentation. Don't get this wrong, the official Scala doc is very good and also the few books that are available are quite useful to get the details of the language, but those have not been written for beginners. For example in Java you find hundreds of books titled something like "Learning OO with Java" you wont find that for Scala which may be a show stopper.
As Hannes mentioned, only do new language introductions within research projects and not productive or even flagship projects. If you have some juniors, that makes the situation even better, take some internal tool, you always wanted and needed and let them create it during a research project. This is also a nice opportunity to experiment with different development-processes. And your juniors most probably like to be challenged and will deliver a good prototype and a very well proofed opinion if Scala can be used as a beginner language.
I believe that most people moving to Scala are experienced and enthusiastic coders. I'd suggest that you get in-house experience with a Scala project with your senior programmers first before forming a strategy for mentoring your junior coders. I'd also suggest that you only involve people who are eager to join in.
I would advocate it. But with the proviso that you have clear guidelines on what language features are acceptable for your team. For example, coding primarily in an imperative style (which is familiar for Java-trained people), or perhaps limiting the employment of recursion or closures.
Also plan for seniors to mentor the juniors. This may take the form of any combination of: pair programming, code reviews, info sessions, regular discussion forums, etc.
The opportunity that scala presents for vastly improved coding on the JVM is too great to pass up. When your seniors get into it I would not be surprised if they find renewed passion for development. When your juniors get into it they will be learning best practice JVM development from the start.
If you choose to go this route, perhaps they'll find easier to use the Scalate framework than a more traditional one like Lift, since it allows mixing HTML with Scala, much in the same way as PHP works.
Scala is a very 'normal' programming language. Any programmer should be able to learn this language. The people that have difficulties learning Scala mostly are experienced with imperative languages and are surprised by the functional concepts. So unexperienced programmers may learn it even faster. In my opinion should be no problem, to assign it to juniors. From a management point of view, I would assign a junior and a senior developer as a team (or more of both, depending on the size of the project).
I think it depends whats more importent for you. If you want to learn as possible about OO Programming and the standard stuff its a bad idea.
But what you really give them is a opportunity to learn something really cool and unique. Witch can be good motivation. Scala has many cool stuff in it. If you can handle Scala you can handle a lot of otherstuff as well.
Talk to the Programmers (all of them) and tell them why you wanne to use scala. Ask if the have to motivation to make and learn something not everybody can do and go the extra mile?
If the are go with it!
My initial thought would be that Scala will be too heavy for them but then I guess because Scala is an OO/Imperitave/Functional hybrid, one could introduce them to the OO/Imperative part of scala until their comfortable, but then again they will probably have bad PHP habits in Scala since scala authors mostly prefer the functional style over the imperative one.
So, it could work, but I would do it for a research project, and definately not for a flagship one.
Edit: Perhaps this should be said also: It seems that functional/OO hybrids like Scala is becoming more popular especially because of how functional languages handles parallel processing as opposed to how we know it in languages like in Java. The amount of cores found in a chip is increasing rapidly, so this is important. However, mentioning PHP, it seems that you are developing web server scripts where threading is less important. PHP doesn't even have threads.
This raises another point. Do you want to develop Scala Web applications i.e. Lift. If so then you have a doubled up learning curve which should also be considered.
Imagine that you would have picked Java and asked whether they could handle Java. If your answer is they could, then they can probably handle Scala.
Scala is only marginally more difficult due to:
No great IDE support. The support ranges from poor to good. Not necessarily an issue for a PHP programmer.
Documentation not as rich as Java
Both Java and Scala have new challenges for a PHP programmer (JVM, new libraries, compiled language, statically typed).
I don't think Scala is a complicated beast, but you do need to understand some of the syntactic sugar and design principles, which would be true of learning Java as well.
Yes, if...
Strategic decision has been made to go with Scala
Company can handle the hit (financial and time) that will come from the steep learning curve.
No, if...
No senior Java, C# or C++ programmers can be put on the project too
Can't find a Scala programmer to act as a lead
Programmers don't have the patience to learn Scala or deal with a language where Jars (libraries) are scattered all over the place, rather than in one or two neat packages like PHP.
*Note: if the junior programmers were C++, C#, or Java Software Engineers rather than PHP, then my answer would be different like, Go for it!
I would not recommend it. My experience of Scala is only from homebrew projects, but I would imagine the currently lousy IDE support, quite frequent API changes and a very flexible syntax (that allows one to hang himself and everybody else participating in the project) would cause a lot of problems in a bigger, more official project.
Give them IntelliJ and throw 'em in the deep end.
Here is a blog post I recently stumbled upon:
http://james-iry.blogspot.com/2008/07/java-is-too-academic.html
It shows that even Java can be too academic to be understood by programmers which have no experience in functional programming. On the other hand, Scala allows to write code the "imperative way", so you can avoid all the FP stuff if you do not understand it. In my opinion, Scala is much more concise than Java, so I guess a "junior programmer" should be able to handle it.
Related
I've read a few questions such as Scala vs Haskell discussing the merits of both languages or which to learn, but I already know that I'd like to learn Scala. I was a Java programmer at uni and now mainly use PHP.
I want to learn Scala as it looks like an improvement on Java for personal projects and I'd also like to learn a functional language to improve my knowledge as a programmer.
I am wondering if it would be a good idea to learn Haskell as an introduction to functional programming as it is purely functional so I'd properly learn it rather than haphazard using bits of functional in Scala without knowing why?
I'd also like to use Haskell for personal projects etc as it looks great, but I don't really see many real world applications of it, seems more used for academic stuff hence wanting to learn it to get the functional understanding then move on to Scala.
Speaking as someone who came from Java, and for whom Scala was a gateway drug to Haskell, I happen to think this is a great idea (learn Haskell first)!
Haskell is conceptually a much simpler language than Scala, and if your goal is to learn how to program functionally, you can't help but do so if you start with Haskell. By design, Scala supports a kind of "legacy mode" of coding in which you don't really have to change your Java (or PHP) habits too much if you don't want to. I think this is a strategic decision--and a good one!--meant to increase adoption amongst crusty Java stalwarts.
But that's not you! You're actually interested in learning something new... so why not go all-out? Learning functional programming in a pure setting, without the clutter and the temptation to regress into old habits, will crystallize the concepts in your brain.
Then by all means return to Scala and learn how it differs from Haskell; it is both weaker in some respects and stronger in others, but you will then be on a much better foundation to appreciate these differences.
I came to Scala from a Java background. Initially I just focused on Scala as a better Java. As time went on I started to use more and more functional concepts in Scala. Eventually I reached a point where I felt I needed a purer understanding of functional programming. It was at this point that I went away and learnt Haskell.
When I cam back to Scala I found it much easier to use a functional style and some of the the concepts I struggled with previously made much more sense.
You don't have to learn Haskell to become a good Scala developers, but I think once you get to a certain level in Scala that having a deeper understanding of functional programming concepts really helps.
I wouldn't do that. If you go straight to Scala (your final aim) you save time. You'll learn functional programming anyway, but as Scala is "less pure" you'll be able to start writing programs in Scala usign some Java-like constructs, which will make the transition simpler.
Even if you go into Haskell, your first programs will be of less "functional quality" than later ones, as only practice improves that. Starting Scala your first programs will be of "less quality" as your first programs in Java or PHP were, but with practice you'll improve. Spending time in unrelated tasks hoping they MAY help, it can result in you wasting that time.
Focus on your aim. If that's Scala, go for it.
UPDATE: I believe this may be relevant to the question. It raises a point on productivity (deliver software) vs seeking "pure knowledge".
The risk of starting directly from Scala, without having played any purely functional programming language first, is that you'll probably be drawn to the procedural solutions a bit too often.
I wouldn't try Haskell as an intro to functional programming, though: not that it's particularly hard - its syntax is amazingly terse - but it's definitely very peculiar (even in the peculiar world of functional programming) and I think you should try with a language you can port more easily to Scala, like Racket or plain Scheme.
To better understand what I mean, look at list comprehensions in Haskell, Scala and Scheme.
I learned Haskell first and then Scala and never regretted. You will gain a much deeper appreciation of FP if you learn Haskell first. Your understanding of the concepts behind FP and why they are important will be seared in. Much of Scala is taken from Haskell (IMHO). It will make more sense when you have the Haskell background. Don't shy away! Your efforts will be rewarded.
For me, I want to learn Scala and functional programming; and, thus simply, I am learning Scala. My study material is Programming Scala. After I have read the early chapter on syntx and stuff, I have skipped chapter covering OO stuff and jumped to Chapter 8 which cover the functional programming stuff. There I let myself struggle with FP.
I read this scala code, which is written in FP way and analyze it. You want to learn Scala for "...an improvement on Java for personal projects." and Haskell for FP intro. So, it seems that first of all, you want to be productive with your java project and then grasp FP as a side effect. To be productive, you have to master the language. There are much to learn and master the language and the only way to master the language is that you have to write the code in that language. As you learn/use Scala, you can't avoid FP out right even if you want to. I have been reading the Scala blogs(the book too) and the authors always go out of their way to do explanation when it comes to FP concept. You don't have to worry about not grasping FP by going Scala route. Yes, you can draw inspiration from Haskell like this when you are learning Scala. Or as Chris Turner above have pointed out, you can delve into more FP when you are already productive with Scala.
You wanna go to point A, why not go to point A directly? If you go via the route of point B (Haskell), you will have to postpone your productivity as Pere Villega mentioned.
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I'm starting to understand Scala and I like it a lot.
How can you position yourself to get a paying job as a Scala developer (assuming those become more common)?
What parts of the Scala ecosystem have the best job potential (Lift, Actors?).
How can you gain credibility with a prospective employer without being able to point to Scala work experience (maybe experience on open-source projects?).
(The above questions are hopefully of somewhat general interest to Scala folk. If you want to factor my particular situation into your response, here are a few details about me: longtime developer (mostly Java) with a Computer Sci PhD; not currently working; I'm tied to a non-cutting edge location (Rochester NY), so I may be limited to remote work.)
Update 2010/07/30:
Thanks for the responses. I'd like to crank up the emphasis on the location issue. I'm tied by family to a location that probably won't have Scala work locally for a long time. Are there realistic prospects for getting remote Scala work, and if so how do you position yourself to get remote work? (A modest amount of travel would be doable, but not a full-on road warrior.)
Also, I was wondering about leveraging my teaching background. Would teaching a Scala class at a local university make a big difference in one's marketability as a developer, or just divert more effort than it is worth?
Pure Scala position:
Finding a pure Scala position is not very easy, but it is getting easier and easier. I am going on my first pure Scala job interview in a few days.
I hope we will see a lot of new systems being written entirely in Scala, and I think these systems will be mostly back-end, heavy duty systems. These systems will be using Scalas less error prone functional style to reduce bugs. I think Akka, SBT and Specs will be important frameworks for the Scala developer (this is not much of a prediction since they are already important).
If you do not find a pure Scala position:
Your credibility comes from your time with Java. Most big companies have heaps of Java code that must be maintained and developed. If it is your job to babysit the old Java code, and as an old Java guru, you should have some say in how this should be done. The first step is to change the Maven setup to allow mixed Java/Scala environment. Moving to SBT is probably your best choice. This is a one time investment you have to do or else you can not proceed!
If you work independently you could probably replace Java with Scala whenever you feel like, most likely when you have to re-factor some old code. Talk about Scala as a "framework" for Java (this is technically a lie) that boosts productivity when speaking to the non technical project manager, this might calm their worrying minds. In the end it will be your responsibility to see to it that Scala indeed integrates with Java. But since Scala does this very well it is not much of a problem. Actually, maintaining old legacy code is not a dream for anyone, so PMs are usually happy if they find anyone who would do it for more than 3 month. Management will probably put up with you rebellion.
If you work in a team it is a bit more tricky. In this case you have to teach the team Scala, or else they will not be able to understand your code. You have to persuade your PM to set aside resources for Scala training (might be hard). When you introduce Scala to a team, start small. My experience is that it takes a while for a Java dude to learn Scala, so this is not done overnight. Therefore, ignore everything that is "hard" when you teach Scala. When the team grasps the basics, start with writing tests in Scala (thank Davetron5000 for this tip), continue to use Java for programming in the application (the production code). Hopefully the team will learn and enjoy Scala and after that, well, it is all downhill from that point.
Good luck!
If I was hiring at the moment, I can tell you right now what questions I would be asking and they would be about the language. It is a hard language to understand at a deep level, even if it seems easy to use and, as a consequence, you might be expected to understand code written in a large number of different styles.
Knowledge of libraries (Akka and Lift being the obvious ones) the sbt build tool is great but it is an extra. I would want to know that you understand:
a bit (well, a lot) about the type system (and higher-kinded types)
something about the typeclasses approach
implicits and the pimp-my-library approach
good scala style (i.e. idiomatic scala)
recursion
the actors approach to concurrency
the standard libraries
functional programming
If you understand the language, you'll pick up the libraries with no problems, I'm sure.
Other libraries:
scalaz for functional programming
scalala for numerical programming (linear algebra etc)
scalaj for interacting with Java
I think your best bet is to get good at Scala and to get visible in the Scala community. These are not necessarily the same thing but luckily they are very closely related in the Scala community. Once you do this there are definitely opportunities to use Scala for fun and profit, whether as a consultant/contractor or as a (remote) full-time employee. As part of getting better and more visible I would recommend becoming active in one of the existing communities (Lift, Akka, ScalaNLP, you name it) or even going out in the wilderness and hacking away to solve a common problem, even if it's just making a native Scala alternative to a popular Java library (e.g. squeryl and Dispatch maybe weren't necessary but they're awesome).
I guess what I'm saying is that contributing to any good, useful Scala code will be good experience and I think the ecosystem is so young that there's no need (or benefit?) to specializing in only one part of it. Of course, if there's a specific subject that Scala is useful for and/or a specific field that benefits from Scala that jumps out to you, direct your attention in that direction.
Having had two full-time Scala jobs at this point, I'd say that the most important thing to do is learn the type system and the standard libraries inside and out. The individual technologies can then be picked up with relative ease.
Also, start using Scala (specifically Specs and ScalaCheck) for testing in your current project, today, if you possibly can.
Finally, as pr1001 said, get visible in the Scala community. Contribute to a project, interact on the mailing list, hang out in #scala on freenode, answer questions where you can.
Take your current job, and implement resume driven development. Just claim that xyz can't get done on schedule without Scala, and then use it. After that, take your project to success and either work elsewhere, open your own business, or continue developing Scala apps at your own company.
It worked for Dick Wall, so it should work for you. :)
Now i know that this one is actually not a very technical question but one that has been bothering me for some time. Actually we are using a lot of C++ and PHP at our company and some of our developers are really hoping for a new and modern language to come by to help us getting more productive. I have been talking about what scala can do and the other coders seem to gain some interest in the language. The tough job is, how do you convince your boss to consider scala as a language for the company. I saw the presentation "Sneaking Scala into your company", but it deals with the situation that you are using Java at your company which we don't.
How do you fight of the usual "that is just esoteric stuff" and "we can already do that in $LANGUAGE" arguments. I was planing to give a talk about Scala, and since I don't have much time I need ideas how to get people interested in the language rather then setting of reactions like "currying? we can already do something like this with boost::bind".
How did you guys do it?
Regards,
raichoo
EDIT: Gave my talk yesterday, people were very excited. My company is going to give it a try! Thanks for all your suggestions.
If you don't already have killer arguments, what are you basing your reasoning on that Scala will make your company more productive?
Don't like something then hunt for reasons to use it at work. Let the reasons speak for themselves..
"A hammer looking for nails"
Using it to do some stuff around the side, as datamigrations, testing and similar things will make sure the necessary experience is built and can give it some exposure.
ScalaTest is really nice to help with acceptance/integration testing. (Yes, I know it is nice for unit testing, but I do not see that immediately happening with C++/PHP target code, and it would probably be unwise).
Proof of Concept and other Prototypes are great for 2 reasons
1) It showcases the capabilities
2) You are certain they will be thrown away if you have to reimplement them in C++/PHP
Now a bad time to introduce Scala would be when you REALLY need it : hopes will be high, it will not immediately work as intended, hopes are dashed and everybody will blame Scala. As a result it will be burnt for a long time in the organisation.
Sooner or later some suit will think it was his idea to introduce Scala and use it on a formal project. If that project is moderately successful, then it is sold.
These kind of changes are complicated people issues, and the harder you push, the harder you will face push-back. On the other hand the persistent mind can move mountains.
Redo some of your work related code in Scala and compare KLOC, code structure and performence, if it looks and works better, show it to your peers and your managers.
In other words:
Talk is cheap. Show me the code.
-- Torvalds, Linus (2000-08-25)
In case of our company (and I assume, many companies share the same scenario), move to Scala (from Java) was initiated by tech people, who 1. wanted to work more productive writing code (living in the 21st century utilize modern approaches), 2. have less troubles building concurrent applications (Actors concept promoted by Scala is a way simpler than Java thread-based concurrency) 2.1 have a simpler way of building scalable staged event driven architectures.
In our company, transition to Scala was more or less simple, because Scala was literlly sold to business people as a library to Java :) -> from their POV, we're still using the same platform (JVM), application servers, etc., but developers are having more fun from their work, and therefore, are more inspired and work more efficiently.
Maybe you could pitch Scala by showing off the suite of tools that is used for development? For example, if you are not already using Eclipse in your company, show your execs a demo of what a modern IDE can do for your productivity.
There is a book called "Fearless Change" (Linda Rising) that describes a pattern language for "powerless leaders" (I LOVE that role title!). SE-radio had a really motivating interview with the author: http://www.se-radio.net/podcast/2009-06/episode-139-fearless-change-linda-rising. Listen up on that interview to collect a few non-technical strategies that can help you in this struggle!
I haven't used Scala yet for any real business code, but I know people who have.
One group used it to write a tool to analyze log files. So they didn't use it for mission-critical business code, but for a non-critical tool to support the project.
Another person I know is an architect and he just went and wrote some Scala code on his own for some production code without telling his manager. After the code was deployed successfully he did tell it. One of the things he mentioned is that because Scala runs on the JVM, the people who support the application don't even notice - to them, Scala is just another library that's included with the application (they were already used to the JVM). Ofcourse this approach is risky and not everybody will be in the position or be willing to do this.
You could start small - use it as your personal preferred scripting language for small things that you need yourself. Tell your fellow developers about it and make them enthusiasts too. If they also start using it then you can step it up to make some side code for your project (such as for example that log analyser tool).
This isn't a really easy task. I would concentrate on the fact that you will be able to produce code and therefore products faster and with a higher quality. That's always the two reasons, business wants to hear from you and will listen to.
Maybe you can show an example of 1-2 very small projects you did in your company with C++/PHP and compare the effort, quality etc. with a similar/the same implemenation in Scala? This would be very impressive and should also convince people who are not on the coding side.
There was a very good talk at Scala Days 2010 by David Copeland:
Sneaking Scala into your organisation
The executive summary: Testing. You can use Scala for testing without affecting release code.
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For the next 3 years I will have to work with the JVM (project requirement) using a very specific third party API. They want Java but I've been given leeway to move away from Java. I was hoping we could move back to the .NET framework so I could develop code in F#, being absolutely in love with OCaml. .NET development has been struck down by our customer. It is a no go.
I've turned to looking, reading, and poking around programming blogs/forums trying to understand which language might appeal to me further: Scala or Clojure. Those seem to have the largest community/fan base. Being experienced with ML languages I see lots of people who compare Scala to ML. However, there are some real naysayers when making this comparison. If Scala was that close to ML my productivity and learning curve would benefit making this switch.
The internet is full of misinformation and wonder if I'm suffering from such. I don't like the syntax of Lisp (don't hurt me!) but if Scala has the warts I'm reading (poor IDE support, in flux Unit testing framework, performance issues) I'm wondering if Clojure is the better option. I want to be productive out of the gate, using functions as first class objects, and minimizing concurrency pain.
So anyways, before I spend too much time on the internet and not working... I'm stuck with the JVM, sick of Java and wondering where to go?
In my opinion, both Clojure and Scala don't have great IDE support, if that's really important to you. That said, here's what I can collect from my reading & experience.
Scala's pros
Faster than Clojure thanks to more static typing
Closer to ML (syntax, type-directed programming)
Bigger standard API (Clojure's APIs grow very slowly, because they want to make sure they find the best idioms before making them public. That said, Clojure still has semi-official supplementary APIs)
Better integration practices with the typical Java toolset (Clojure is still making some choices, so less firmly established yet on this regard)
Older than Clojure (but Clojure is built on top of a very old and proven core: Lisp)
People say it has chances to reach mainstream, while they wouldn't say the same about Clojure
Clojure's pros
Incredibly easy, fast and right concurrency thanks to MVCC-based STM and other concurrency mechanisms
Immutability by default helps doing the right thing first
More stable standard API
When things change, usually you don't have to rewrite any existing code
(Scala's collections are being remade again for 2.8)
(I have also read somewhere that it's common knowledge that Scala's Actors implementation needs a rethinking and rewrite.)
Easier to learn (small language, being a (very-clean) Lisp)
An opportunity for you to grow by learning something different
Clojure's performance will only get better with time; there's still room for nice optimizations in the compiler
Scala's tying to Java feels more limiting than Clojure's (interactions between Scala's and Java's static type systems). One could sometimes say the same about Clojure (Object-Orientation's support is not a 1:1 fit, but support for this will soon get better)
Rich Hickey has a gift for making choices that put Clojure in the position of having technical leading features that will be adopted by other languages in the decades to follow. And he also has a gift for explaining them. So use them today in Clojure, or wait to use them in another language in some number of years. :)
On distributed concurrency
If your concurrency needs are distributed, Clojure doesn't yet have anything for this unless you run it on top of Terracotta or something similar, in which case you'll be able to use all its concurrency features. If you do, you will end up with a better distributed concurrency experience than with Scala's Actors, IMO.
Conclusion
IMO Scala tries to do everything, and succeeds at doing most of it. Clojure doesn't try the same thing, but what it focuses on is more than enough and succeeds so well that most people really knowing Clojure wouldn't want to go back to something else. Disclosure: my personal preference goes, of course, to Clojure. I hope I've been able to be objective in what I wrote.
Have you considered Groovy? I don't think it is quite as functional as Scala/Clojure, but it's certainly a lot more functional than Java**. In general, I can get the same work done in Groovy with about 50% of the code it would take me in Java.
This is because Groovy is syntactically similar to Java and provides seamless access to the JDK libraries, but the addition of a lot of language features (closures, meta-programming, properties) and dynamic typing eliminates almost all the boilerplate associated with Java programming.
** I mean functional in the sense of 'functional programming' rather than 'working correctly'
I'll address the points you raised about Scala.
IDE support:
Scala doesn't have the same level or IDE support Java has -- or, for that matter, that F# should have with VS10.
That said, it has one of the best (maybe even the best?) IDE supports on JVM, outside Java. Right now NetBeans is good enough, and people have consistently said IDEA is still better (hearsay). The Eclipse plugin is unstable though.
But you mentioned a 3-years range, and the IDE support for Scala should be greatly enhanced once Scala 2.8 is out, as it will provide some compiler-support for IDEs. There's no release date defined, but it looks to be within the next six months, maybe three. And the Eclipse plugin will be updated right along with it.
In flux unit testing framework:
Yes, if you meant it is vibrant, evolving and well supported, instead of stagnant and abandoned. ScalaTest, Specs and ScalaCheck are top quality frameworks, compatible between themselves, and compatible with other Java frameworks and libraries, such as JUnit and JMock.
The testing frameworks, in fact, are almost a child poster of what is possible with Scala.
EDIT: Scala has basic unit test support in its standard library (scala.testing.SUnit). However, given that many superior, actively-supported and free alternatives have appeared, this has been deprecated and will likely not be part of the library shipped with Scala 2.8.
Performance issues:
I'm unaware of any, aside from the fact that you can write lousy code, just as with any other language. People not used to functional programming will often do stuff that's not efficient, such as not using tail recursion, or concatenating lists, and the paradigm shift that Scala enables brings that to light.
At any rate, you can write Scala code as fast as Java code (even faster with some upcoming features). And you can write Scala code with functional features almost as fast as Java code.
Quite frankly, get another job.
If you are to spend the next three years feeling uncomfortable on what you're doing, you should consider looking for more attractive alternatives.
Even if you manage to get a language you like, if you are part of a team ( which I guess you are ) the rest of the team might not like that language. If the rest of them code in Java and you in "fill in the blank" programming language, then problems may arise.
It is not that bad after all.
Talk with your boss, let him know how do you feel. Start looking for alternatives and have a nice and professional "leave".
There is no reason why you can't still have a good relationship with your current boss. If eventually they have a new project for .net you may come back. Talk about that also with them. Leave your doors open.
Its not really a zero sum game, learn them all!
ps: i vote for Clojure, i find it the most fun!
You should consider yourself lucky that you can use the JVM, because the JVM is becoming more and more popular for alternative programming languages than Java.
Besides Java there's Groovy, Scala, Clojure (a Lisp dialect on the JVM), JRuby (Ruby on the JVM), Jython (Python on the JVM), Jaskell (Haskell on the JVM), Fan (runs on the JVM as well as the .NET CLR) and lots more, and there's also an OCaml-Java, OCaml that runs on the JVM.
So, there's lots of choice in programming languages on the JVM, from purely functional to simple scripting and anvanced OO languages.
Tool support for Scala and Clojure may be immature, but it's steadily improving.
Since you like F#, then Scala is most likely your best bet. I say try it out and form your own opinion - you might find that the things people gripe about are things that don't matter to you, or things you can work around.
Don't forget jRuby, and note that an IDE is optional for non-Java
I think you have a great situation. How many people get permission to choose the implementation language? With everything available for the JVM having your environment chosen is not much of a restriction.
You won't need great IDE support in the less verbose languages
In a language as powerful as Ruby with no type declarations, you don't need an IDE at all
Scala was developed specifically to cure the verbose-java-blues
Count yourself lucky that you have three years of work lined up :-)
Clojure might be fun and provides functional concurrency-safe design patterns
Noop? http://code.google.com/p/noop/ (experimental though)
In terms of IDE support and other doubts you're having, Clojure doesn't do any better than Scala. And for a person with ML/F# background (or generally that in strictly, statically typed FP languages), you'll definitely find Scala much closer to what you're used to.
If you like ML you might like CAL which is more-or-less Haskell 98 for the JVM.
It is high quality and very stable, and has good IDE support on Eclipse, but sadly is no longer under active development.
I've been asked to run a workshop and coding dojo soon for people to try out Scala and try to build something with it. The attendees are all going to be new to Scala, and could come from any of a number of languages (I'm presuming they can code in at least one mainstream language - I'm including syntax comparisons with Java, C#, Python and Ruby).
Part of the appeal of Scala is that it's practical - you can use it as a drop-in "power Java" (Java with less syntactical clutter, closures, immutability, FP, traits, singleton objects, nifty XML handling, type inference etc.) that still runs on the JVM (and on the .NET CLR supposedly) and doesn't require you to change build tools, server infrastructure, libraries, IDEs and so on. Most of the katas I've seen have been fun but not 'real world' - mathematical challenges like Project Euler and so on. These don't seem appropriate as we're trying to explore the use of it as a practical, real world language that people could consider using for both hacking and work, and because people aren't necessarily going to be too familiar with either the deeper parts of the Scala syntax or necessarily of the concepts behind functional programming.
So, has anyone come across any more practical, everyday katas rather than arithmetical 'problem solving' ones? Katas, that is, that can test whether the language, libraries and tools can satisfy the use cases of the actual day-to-day programming most people have to do rather than testing out. (Not that the impractical ones aren't fun, but just not appropriate for the kind of thing I've been asked to run.)
If I can't find good examples, I'm thinking that it might be useful to try and build something like a library catalogue - the event is for programmers who primarily work on building infrastructure for universities (and in education and culture - museums, galleries, schools, libraries and so on). It's a bit boring though, but it's the sort of thing that the attendees work on in their day-to-day existence. Any suggestions?
There is a creative commons licensed introductory training course with hands-on exercises here:
http://github.com/javaBin/scala-training-slides
http://github.com/javaBin/scala-training-code
The slides are in Open Office format. If you don't have this installed, you can upload them to SlideShare, which will convert them for online viewing.
Most of the programming examples in my blog are, effectively, coding dojo exercises. Particularly the matrices series, but also the puzzles and 99 beers. Now, don't disregard the matrices series as being "mathematical", because the problems I concern myself in it are related to the construction of classes in Scala, not to doing fancy algorithms. In fact, I pretty much skip over the mathematical algorithms themselves.
Now, 99 Scala Problems and pretty much everything from Project Euler are nice exercises for the functional part of Scala, but I understand that not to be your emphasis. I do recommend retronym's answer. Rosetta Code, not being functionally oriented, might have more general examples. There are many with Scala examples, of course, though you may wish to consider other tasks as well, for ideas.
There's lot of cool things to learn about Scala, but one has to be careful at beginner level. For instance, I would not speak of dependency injection (self types and the cake pattern) or of type classes (the pattern that simulates such with implicits).
Do look as well at the material on the Scala Lang site, particularly the Scala by Example document.
EDIT
I have now overseen several Scala dojos, so here's a bit of stuff I've learned from then:
Problems: they have to be fun, not-quite-easy, not-that-hard, and that has to be everyone's opinion.
We use the Dojo Puzzles site, which is in Portuguese so it won't be of use for most people here. If there's a similar site in English, I'd love to hear about it.
The way it works is you ask for a random problem, look it over and discuss to see if you'll pick it up or not, and then indicate by saying you'll use it, you'll not use it, or maybe you'll use it but you'd like to see another one. This vote gets registered and you can see how many people picked up a problem, which helps deciding whether to pick it up or not in first place.
Scala knowledge: it turns out it's not that important to introduce key concepts of Scala language beforehand, particularly if some of the participants have basic knowledge.
In my experience, setting up the testing environment with a trivial "pass" test and explaining how people should write the tests is often enough to get people started. If you feel someone is struggling to write something, give a quick explanation and get on with it.
Teaching Scala: if you do set out to teach Scala, keep lessons short and follow up with a dojo. In this case, keep a set of dojo problems that are adequate to the lesson, and, depending on how many lessons you want in one day, short.
It helps imposing artificial constraints on how one must solve a problem. Some examples of constraints I have put in practice are no classes and single-expression methods (that is, no multiple statements or val/var declarations). The point of these constraints is making it impossible for people to solve the problem in the way they are used to, which gets them to explore the language in search of alternatives.
I have the final results of three dojos done at my current job in this repository.
At the moment we are using the Randori Kata format, but without fixed time or break, and with retrospective at the end of the dojo, not at the beginning of the next. This, however, is just were we are currently at -- we have experimented many variations, and we are still evolving.
Perhaps you could have a look at the Ruby Quiz material for inspiration.
Take a look at Scala by example from Martin Odersky (creator of scala)