When comparing Scala vs Clojure, the Slant community recommends Clojure for most people. In the question“What is the best programming language to learn first?” Clojure is ranked 14th while Scala is ranked 20th. The most important reason people chose Clojure is:
Clojure programmers are highly encouraged to use immutable data in their code. Therefore, most data will be immutable by default. State change is handled by functions (for transformations) and atoms (an abstraction that encapsulates the idea of some entity having an identity).
Ranked in these QuestionsQuestion Ranking
Pro Immutable values
The immutable values make it perfect for working with concurrency
Scala supports both Functional and Object Oriented styles of programming. Beginners can learn both paradigms without having to learn a new language, and experts can switch between the two according to what best suits their needs at the time.
Pro Type inference
Scala offers type inference, which, while giving the same safety as Java's type system, allows programmers to focus on the code itself, rather than on updating type annotations.
Pro Compiles to JVM bytecode
Aside from Java itself, Scala is by far the most popular of the many JVM languages. If you're developing for Android, or a similar JVM-only platform, or otherwise need out-of-the-box cross-platform compatibility, but the performance of a compiled language, Scala is the way to go.
Pro Very good online courses
On coursera you can find great introduction to Scala by Martin Odersky.
Pro Type inference leads to a simpler syntax
Pro Expressive functional programming abstraction for reusable and safe code
Pro Immutability is the default
Clojure programmers are highly encouraged to use immutable data in their code. Therefore, most data will be immutable by default.
State change is handled by functions (for transformations) and atoms (an abstraction that encapsulates the idea of some entity having an identity).
Pro Minimal syntax
Being a LISP, programs are simple: they're just functions and data. That it doesn't get bogged down with syntax or the loftier FP concepts like monads makes it one of most approachable functional languages for beginners.
Pro Tries to solve problems as simply as possible
Simplicity is one of the pillars on which Clojure is built. Clojure tries to solve many problems in software development as simply as possible. Instead of building complex interfaces, objects or factories, it uses immutability and simple data structures.
Pro Good for writing concurrent programs
Since Clojure is designed for concurrency, it offers things like Software Transaction Memory, functional programming without side-effects and immutable data structures right out of the box. This means that the development team can focus their energies on developing features instead of concurrency details.
Pro Huge ecosystem of libraries to work with
There's a very large ecosystem of high-quality Clojure libraries which developers can use. One example is Incanter. It's a great data analytics library and a very powerful tool for dealing with matrices, datasets and csv files.
Pro Cross platform
Clojure compiles to JVM bytecode and runs inside the JVM. This means that applications written in Clojure are cross-platform out of the box.
Pro Rich Hickey
The creator is so awesome, he's a feature. Just look up his talks and see why.
Clojure has an elegant macro system which enables language additions, Domain-specific languages (DSLs), to be created much easier than most other languages (with the exception of Racket, perhaps).
Pro Dynamic language
A superb data processing language. While rich type and specification systems are available they are optional.
Pro Great tool used in automating, configuring and managing dependencies available
Leiningen is a very useful tool for Clojure developers. It helps wiht automation, configuration and dependency management. It's basically a must for every Clojure project.
Pro No C/Java syntax
Pro Game is available with which you can learn Clojure
Nightmod is a tool used to make "live-moddable" games. It displays the game's code while you are playing and allows you to inject new code using Clojure. This can be a fun and useful experience for people trying to learn Clojure.
Con Can be intimidating for beginners
Scala is an industrial language. It brings functional programming to the JVM, but not with a "start small and grow the language" perspective, but rather a very powerful language for professional programmers.
Con Way too complex for beginners
Even for seasoned programmers it's a difficult language.
Con Static type system inherits cruft from Java
The type system is too complicated yet still less powerful than Haskell's.
Con Confusing error messages
Clojure's error messages more often than not are very confusing. They usually involve stack traces that do not thoroughly explain where the error was caused or what caused it.
Con Syntax can be alien / jarring for those used to other Lisps
Perhaps some may consider this attribute an advantage, but I do not. Clojure does not attempt to maintain significant compatibility with other Lisps. So, if you already know a Lisp or are used to the way Lisp works in general, you'll probably be confused if you take a look at Clojure. See these resources for more details on this subject:
Con Tied to the JVM and it's limitations.
Some language constructs were obviously created as workarounds for JVM limitations. This makes the language much less elegant than it could have been.
Also, the JVM has a very cumbersome FFI.