Top 16 Functional Programming Languages To Know

‘Known yet unknown’ is one of the biggest ironies of technological trends. Trends can change the entire software development world in just a few days. Why are we talking about this? Have you heard the term ‘Functional Programming’? You might say it’s in trend these days. Yes, functional programming has been around for the last 60 years but it is more like a ‘known yet unknown’ thing to the development world. Things are changing and at present, Every developer seems excited to learn it, use it, and leverage it to create modern, secure, and useful products in less time.

Let’s move further with the introduction to functional programming. Also, here in this blog post, we will be talking about the top 16 functional programming languages that are popular and used by developers worldwide.

What Is A Functional Programming Language?

Functional programming is a programming paradigm. Generally, a paradigm is a way or a model or you can say, a pattern solving a particular problem in computer science.

Taking this definition to next level, functional programming involves writing code in pure functions. It is a declarative programming paradigm where function definitions are trees of expression that map values to other values. It is opposite to the imperative paradigm where the sequence of statements can update the running state of the program.

What Is Functional Programming?

Simply, functions are a set of instructions grouped to achieve a specific outcome. Here, pure functions are given more importance as pure functions are not allowed to interact with outside elements and they always return the same output, given the same input.

Pure functions are not allowed to change their state which is exactly opposite to the OOP where any method can mutate the state of the objects. Pure functions are also proven best for concurrency as there is no shared state between functions.

Functional programming is great for data analysis and machine learning. Programmers are falling in love with it because of powerful features such as –  no nulls, higher-order functions, no exceptions for error handling, immutable data structures, pattern matching, and function composition operators.

Advantages Of Functional Programming:

Here are some of the benefits of functional programming that are admired by developers.

• Shorter code
• Easy debugging
• Modular
• Parallel programming
• Increased maintainability
• Code readability

Many functional programming languages are in use today in many industries. There are many other programming languages that support functional programming or implement such features. It is widely used in some specific domains such as the web, statistics, financial analysis, machine learning, and so on.

Functional Programming Languages: Best Functional Programming Languages To Learn

Here is the list of the most popular functional programming languages and languages that support programming in functional style or have functional as well as OOP capabilities.

• Elixir
• Erlang
• Common Lisp
• Haskell
• F#
• Clojure
• Elm
• Racket
• OCaml
• Idris
• PureScript
• Wolfram
• Scala
• Python
• Kotlin
• JavaScript

Let’s explore the functional programming languages list in detail.

Elixir:

Elixir is the most popular programming language in the world. It is a functional, general-purpose, and concurrent programming language that runs on the BEAM virtual machine. It is popular for its suitability to build low-latency, fault-tolerant, and distributed applications.

Elixir is built on top of Erlang and uses features of Erlang, Ruby, and Clojure to become a high-concurrency and low-latency programming language. It is used by world-recognized companies that serve millions of people concurrently such as Discord, PagerDuty, Pinterest, Bleacher Report, Inverse, The Outline, and so on. It was created by José Valim whose goals were to create a language that can be used for large-scale sites and apps.

It is designed to handle large data volumes at speed and because of its capabilities. Elixir is mainly used in telecommunication, eCommerce, and finance industries. It is a very pragmatic language. Phoenix is a development framework written in Elixir which is popular for its great performance.

It is superior for reliability and concurrency as it builds on top of Erlang. The community and the core Elixir team are putting their best efforts into the Elixir ecosystem which is a combination of high-quality libraries, forums, and skilled professionals.

It is a great language to start learning functional programming, try it!

Erlang:

Do you know? Erlang is used to code WhatsApp. Erlang is a general-purpose, concurrent, functional programming language, and garbage-collected runtime system. It is specifically designed for concurrency, distribution, and fault tolerance. It is suitable for building distributed, real-time, and concurrent systems such as telecommunications, database applications, servers, and highly-available systems.

Erlang was originally proprietary software used in Ericsson and developed by Joe Armstrong, Robert Virding, and Make Williams in 1986. It is used interchangeably with Erlang/OTP (Open Telecom Platform) which is a collection of useful libraries, tools, and middleware written in the Erlang and it is an integral part of the Erlang open-source distribution.

It is used by a number of extremely scalable and large systems such as Facebook, AXD301 ATM switch, Gambit Research, RabbitMQ, Wavenet, AdRoll, Bluetab Solutions, Samsung, Goldman Sachs, BT Mobile, Corelatus, Netkit Solutions, Mitel, RAD, and many others.

Not only in telecommunications, but Erlang is also being used in many industry domains such as Fintech, healthcare, automotive, IoT, gaming, and Blockchain.

Common Lisp:

Common Lisp is a dialect of the Lisp programming language. It is a general-purpose, dynamic, and multi-paradigm language that supports a combination of procedural, functional, and object-oriented programming styles. Lisp is one of the oldest programming languages and there are many dialects of Lisp that have existed over time.

Being one of the oldest programming languages, Lisp established many ideas in software development. The best-known general-purpose Lisp dialects are Racket, Common Lisp, Scheme, and Clojure.

It supports first-class functions and offers evolutionary and incremental software development. It is widely used in some of the greatest software and systems such as ITA Software, London Tube, Mirai, PWGL, Boeing, Airbus, Yahoo, Grammarly, NASA, Microsoft, and many others.

Common Lisp is mainly used to develop research applications, prototyping, and AI apps.

Haskell:

Haskell is considered the ‘mother’ of all functional programming languages. Haskell is a general-purpose, statistically typed, and purely functional programming language offering type inference and lazy evaluation. It is older than Java and became a pathfinder for many advanced features in programming languages.

It is widely used in academia, research, and industrial applications. Haskell functions have no side effects as it is a purely functional language. It offers lazy evaluation, lambda expressions, pattern matching, type classes, type polymorphism, and list comprehension.

Haskell’s notable applications include several world-known systems such as GHC, Agda, Pandoc, Cryptol, Cardano Blockchain platform, Target, Pugs, Xmonad, Bluespec, Linspire, and others. Haskell is a great choice to start exploring what functional programming is. It is mostly preferred for academics and research.

F#:

F# is a general-purpose, functional-first, strongly-typed, and multi-paradigm programming language that consists of functional, imperative, and object-oriented methods. It is most often used as a cross-platform (Common Language Infrastructure) CLI language on .NET. It is similar to OCaml with few differences.

It is a member of the ML language family and can also generate JavaScript and GPU code. It has great tooling support, an open-source community, and a rich ecosystem backed by Microsoft and The F# Software Foundation. It is used in a variety of apps from web APIs to data manipulation, data science, machine learning, and interactive programming apps.

It offers functional-first features such as type inference, first-class functions, pattern matching, and object support. F# is a great fit for data science and machine learning apps as it is robust, performant, and fast language.

Clojure:

Clojure is a popular dynamic and functional dialect of the Lisp programming language on the Java platform. Clojure features immutable and persistent data structures and also allows developers to manage identity and states explicitly. This gives developers a big advantage to create concurrent and fast programs.

Rich Hickey created Clojure language with the goal of creating a modern Lisp for functional programming. It supports functions as first-class objects, a macro system, and a read-eval-print loop. It also offers support for lazy sequences, recursion, a reactive agent system, and higher-order functions. The primary platform of Clojure is Java but many other target implementations exist.

It is used by many world-recognized companies that include Walmart, Chartbeat, Netflix, Puppet, Circle CI, LinkedIn, Salesforce, Cisco, Boeing, ThoughtWorks, Atlassian, Room Key, Pisano, GO-JEK, Freshcode, LendUp, and so on.

Elm:

Elm is a domain-specific programming language specifically used for building web browser-based GUIs. It is a purely functional language and offers usability, simplicity, performance, and robustness. Elm compiles to JavaScript. Some noticeable features of this language include no runtime exceptions, easy refactoring, friendly error messages, great performance, module system, static typing, and interoperability with HTML, CSS, and JavaScript.

It was created by Evan Czaplicki in 2012. Being a functional language, it supports anonymous functions, functions as arguments, and functions can return functions. It is widely used for front-end web development. Some of the limitations of Elm include a large amount of boilerplate code, no active community, no support for higher-kindred polymorphism and type classes. Elm is used by a large number of companies in production such as Watermark, Basiq, Actcast, GlobalWebIndex, Day One, EXR, Microsoft, Emirates, treefin, NoRedInk, thoughtbot, and so on.

Racket:

Racket is a dialect of Lisp and a descendent of the Scheme. Racket is a modern, general-purpose, multi-paradigm programming language and a multi-platform distribution that includes the language itself, standard library, IDE, development tools, and a set of additional languages.

Racket is good for exploring ideas and rapid prototyping. It is also used in commercial projects and web applications. DrRacket comes as a self-hosted IDE that is widely used in computer science courses to teach Scheme and Racket. Racket is mainly used for scripting, computer science education, and research.

The core Racket language is popular for its massive macro system that enables building domain-specific languages and language constructs.

OCaml:

Ocaml, Objective Caml is a general-purpose, multi-paradigm language that extends the Caml dialect of ML with object-oriented features. It is a free and open-source project managed and maintained by the French Institute for Research in Computer Science and Automation.

OCaml combines functional, imperative, and object-oriented programming under an ML-like type system. It offers features such as static type system, type inference, pattern matching, parametric polymorphism, exception handling, and tail recursion.

Some of the globally-popular companies use OCaml in their production environment such as Bloomberg, Facebook, Jane Street Capital, GeneWeb, Flow, Hack Programming language compiler, Citrix Systems, and so on.

It is as old as Java but it has a very small community and learning resources. You won’t find great libraries and frameworks support. This makes OCaml less popular compared to the other functional languages.

Idris:

Idris is yet another purely-functional programming language. It offers many features borrowed from mainstream functional programming and proof assistants. The key features of Idris include dependent types, lazy evaluation, and totality checker. It encourages Type-Driven Development where types are tools for creating programs.

Type-driven development is a notable feature of Idris and helps developers improve the performance and accuracy of the program. It prioritizes the management of side effects and support for embedded domain-specific languages. Code written in Idris is easy to maintain and test.

Idris is known for its state-of-the-art type system which makes it unique.

PureScript:

PureScript is a strongly-typed and purely-functional programming language that compiles to JavaScript. Syntactically, it is similar to Haskell. It has also a set of great features such as persistent data structures, higher kinded types, pattern matching, type classes, and functional dependencies, and higher-rank polymorphism.

It was designed by Phil Freeman in 2013. It is widely used to develop web applications, web servers, apps, and more. It has an active community and excellent tooling, making this language easier to pick by beginners.

Wolfram:

Wolfram language is a general, multi-paradigm programming language developed by Wolfram Research. It emphasizes functional programming, rule-based programming, and symbolic computation. It was a part of the initial version of Mathematica in 1988.

It is majorly used for real-world data computing, algorithmically-oriented programming, reactional programming, rapid concept deployment, analytics, IoT, education apps, legacy modernization, and multiplatform deployments. Wolfram is playing a key role in the development of new ideas in research, education, and science.

Scala:

Scala is not functional but it supports functional programming and object-oriented programming. The reason we consider Scala for functional programming is, it combines OOP and functional programming in one concise, high-level language.

It is a modern, multi-paradigm programming language that runs on top of Java Virtual Machine (JVM). It integrates features of both – object-oriented and functional languages. Scala is statically-typed, extensible, and fully interoperable with Java.

Considering the functional level context, it supports many features of Scheme, Standard ML, and Haskell that include lazy evaluation, higher-order types, immutability, pattern matching, and type system supporting algebraic data types, raw strings, and optional parameters. It is used by prominent companies around the world such as Foursquare, The New York Times, Airbnb, SoundCloud, Verizon, Morgan Stanley, Firebase, LinkedIn, Twitter, MeetUp, Coursera, Apple, Walmart, Databricks, and many others.

Scala has received many accolades such as the most popular programming language, alternative languages of the JVM, and JVM-based popular programming language.

Python:

Python doesn’t need any introduction. It is not functional language but it supports coding in a functional, declarative style. Its design offers support for functional programming through functions, generator expressions, list comprehensions, sets, and dictionaries. It is inspired by Haskell and Standard ML.

It embraces a “there should be one – and preferably an only one-obvious way to do it” design philosophy. It is one of the popular programming languages used for a variety of apps and systems. Python community is the largest one and is considered its greatest strength. It is more commonly used in AI, machine learning apps, a scripting language for web applications, scientific computing, information security industry, and many components are written in Python.

Amazon, Instagram, NASA, Google, Yahoo, Wikipedia, Reddit, ITA, Spotify – these are some of the organizations that use Python.

Kotlin:

Kotlin is a cross-platform, statically typed, and general-purpose programming language but it can be used to code in functional styles. It is a great choice for exploring functional programming as it offers first-class support for features such as function types and lambdas, higher-order functions, and many more.

It is concise, type-safe, and faster. Kotlin is easier to adopt as it is 100% interoperable with the Java programming language. Kotlin is used for server-side, client-side web apps, desktop apps, and native development, as well as it is supported as a first-class language on the Android platform. It is used by many companies such as Square, Pinterest, Basecamp, Corda, and so on.

Kotlin has a very vibrant and active community with support forums, events, and resources.

JavaScript:

JavaScript is primarily a scripting language and it is not widely known as a functional language but it does support functional elements.

JS is high-level, often just-in-time compiled, and multi-paradigm. It supports dynamic typing, first-class functions, and prototype-based object orientation. JavaScript is one of the core technologies of the World Wide Web along with CSS and HTML. Being a multi-paradigm language, it supports event-driven, functional, and imperative programming styles.

It has much in common with Scheme. JavaScript is used almost everywhere in every kind of app and web.

Best Functional Programming Language: Talk Of The Town

It’s in trend.

Yes, functional programming allows developers to solve complex problems in a simpler way. It improves the maintainability, accuracy, and modularity of the code. It is different from the OOP but it aims for performance, stability, and reliability.

While we are not saying OOP should not be used or completely replaced by FP. A combination of both is what requires to build a modern, scalable, and reliable system. You can choose the paradigm of your choice based on your requirements. Functional programming has quite some benefits and that should be taken into consideration when you think about building a new software product.

Do you know any functional programming language?

What functional programming language will you pick to start exploring functional programming?