The name Scala is blended with scalable and language, signifying that it is designed to grow with the demands of its users.
- It was designed by Martin Odersky.
- Its developer is programming method laboratory of École Polytechnique Fédérale de Lausanne.
- It first appeared on 20th January 2004.
- Typing discipline is static, strong, inferred, and structural.
- The platform on which Scala works is JVM, JavaScript, LLvm.
- The extensions used in Scala for saving files include .scala or .sc.
Scala provides functional programming support and strong static type system, which makes it a great general purpose programming language.
To make Scala source code executable code which runs on Java virtual machine it is intended to be compiled to Java bytecode. It provides language interoperability with java so that libraries written in both languages can be referenced directly in Scala or Java code. Being object-oriented Scala uses curly brace syntax reminiscent of the c programming language. The various features offered by Scala which make it a great functional programming language include: lazy evolution, Standard ML, and Haskell, including currying, pattern matching, type inference, immutability, Scheme.
A small example of scala program:
"Good Morning" example
The Good Morning program written in scala has this form
Object GoodMorning extends App {
println("Good Morning")
}
There is no class declaration and nothing is declared to be static like in case of java; a singleton object created with the object is used instead. You can easily place static variables and methods in a singleton object with the same name as the class name, which is then known as a companion object. The underlying class for the singleton object has a $ appended.
The program is stored in the file named GoodMorning.scala, and then the user compiles it with the command:
$ Scala GoodMorning.scala
And runs with
$ Scala GoodMorning
Commands can be directly entered into the Scala interpreter, using –e option:
$ Scala ‘println("Good, Morning")'
In place of constructor parameters, Scala has class parameters, which are placed on the class similar to the parameter to a function. When it is declared with a Val or var modifier, fields are also defined with the same name and automatically initialized with the class parameters.
Default visibility in Scala is public.
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Syntactic Flexibility in Scala:
Scala has a good deal of flexibility as compared to java. Following are some examples.
- Lines are automatically joined if they begin or end with a token t, or if there are unclosed parentheses or brackets, semicolons are not necessary.
- You can use any method as an infix operator "%d apples". Format (num) and "%d apples" format num are equivalent. Arithmetic operators like + and<< are treated just like any other methods since function names are allowed to consist of a sequence of arbitrary symbols; the only special treatments that such symbol-named methods undergo concerns the handling of precedence.
- Methods apply and update have syntactic short forms.foo () where foo is value (singleton object or class instance)-is short for
- apply (), and foo () =42 is short for
- update (42). Similarly, foo (42) is short for
- apply (42).
- This is used for collection classes and extends too many other cases, such as STM cells.
- Scala distinguishes between no-parens (def foo=42) and empty-parens (def foo () =42) methods. While calling an empty parens method the parentheses may be omitted, which is useful when calling into Java libraries that do not know this distinction.
- Method name should be ending in colon (:) except the argument on the left-hand side and the receiver on the right-hand side. Class body variables are transparently implemented as separate getter and setter methods.
- You can use curly braces instead of parenthesis in methods calls which allow pure library implementations of new control structures. The curly braces variant allows the expressions to span multiple lines.
- For-expressions can accommodate any type that defines monadic methods such as map, flat Map, and filter.
- These choices collectively serve as the purpose of allowing domain-specific languages to be defined in Scala without needing to extend the compiler.
Usage of Scala
Central drive behind Scala is to make life easier and productive for the programmer. This is done with three principal techniques: firstly It adds expressiveness, it tightly fuses object-oriented and functional programming concepts in one language, and then protects existing information by running on the Java virtual machine and interoperating seamlessly with java. Secondly, it cuts down on boilerplate, so that programmers can concentrate on the logic of their problems.
Scala offers a toolset to write scalable concurrent applications in a simple way with more confidence in their correctness. Scala is an excellent base of parallel, distributed, and concurrent computing, which is widely thought to be a very big challenge in software development but by the unique combination of features has won this challenge.
when it comes to parallelism, concurrency, and distributed computing every bit of mutable state is a potential liability and Scala's functional programming genes are an advantage to this. Scala design encourages users to search for more scalable functional alternatives but it does not prevent traditional imperative solutions.
The language is also a joy to be used outside these advance domains. It can perform any programming task, from large mission-critical systems to one line commands in the scala shell.
Using Scala apps are less costlier to maintain and easier to evolve Scala because Scala is a functional and object-oriented programming language that makes light bend reactive and helps developers write code that's more concise than other options. Java libraries are easy to use from Scala, and vice versa.
Scala is being called the next wave of computation engines because it relies more on the speed of data processing rather than the size of the batch, and the ability to process event streams in real time, hence it has taken the world of fast data.
An example related to that movement which is rapidly gaining mainstream momentum are Apache Flink, Apache Spark, Apache Kafka and Akka Stream.
Disadvantages of Scala
There are some disadvantages which keep Scala from reaching the top. Those disadvantages are as follows:-
- You can think of Scala ass double-edged sword because with Scala you switch back to an object-oriented paradigm. So there is no compulsion for you to think functionally.
- Sometimes type information is a bit harder to understand because of it being a hybrid of functional and object-orientation.
- It runs on JVM so it has no tail-recursive optimization. You can use the @tailrec annotation for partial benefits as a workaround.
- Scala has a limited developer pool. It is easier to find Java developers in number, not every Java developer has what it takes to code in Scala.
Above disadvantages are caused by the following factors.
- Limited community presence. Resources to help you in troubleshooting your issues there are limited online communities available.
- Hard to learn. Syntactically, Scala is significantly different from traditional java. It presents a completely different paradigm.
- Lack of ease of adoption. You need a team which is eager adopters for Scala to be feasible otherwise coding in a team you will rarely find anyone writing purely in Scala.
- Limited backward compatibility. Whenever a new version of Scala is released it is incompatible with the previous version, and hence results in a lot of wheel-reinventing headaches and product delay.
Conclusion:
We have studied about Scala its benefits and importance and if Scala makes for what it takes to run your project, you must definitely explore it and give it a try.
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