What are the best languages for learning functional programming?

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Aug 18, 2022

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28 Options Considered

Best languages for learning functional programming	Price	Site	Paradigm
89 Haskell	-	https://www.haskell.org/	functional
86 Elm	-	-	-
76 F#	-	-	-
74 Elixir	-	https://elixir-lang.org	-
-- Idris	-	-	-

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score 146 · Answer 1

Haskell

Top Pro

Forces you to learn pure functional programming

It is pure and does not mix other programming paradigms into the language. This forces you to learn functional programming in its most pure form. You avoid falling back on old habits and learn an entirely new way to program. See More

Top Con

Language extensions lead to unfamiliar code

Haskell's language extensions, while making the language incredibly flexible for experienced users, makes a lot of code incredibly unfamiliar for beginners. Some pragmas, like NoMonomorphismRestriction, have effects that seem completely transparent in code, leading beginners to wonder why it's there. Others, like ViewPatterns, and particularly TemplateHaskell, create completely new syntax rules that render code incomprehensible to beginners expecting vanilla function application. See More

PoliteMagec's Experience

Outstanding documentation and massive amount of guides makes it manageable, even as a novice in functional programming. See More

Specs

Site:https://www.haskell.org/

Paradigm:functional

Type System:static

Top Pro

Open source

All Haskell implementations are completely free and open source. See More

Top Con

Difficult learning curve

Haskell lends itself well to powerful abstractions - the result is that even basic, commonly used libraries, while easy to use, are implemened using a vocabularly that requires a lot of backround in abstract mathematics to understand. Even a concept as simple as "combine A and B" is often, both in code and in tutorials, described in terms of confusing and discouraging terms like "monad", "magma", "monoid", "groupoid", and "ring". This also occasionally bears its ugly head in the form of complicated error messages from type inference. See More

Top Pro

Highly transferable concepts

Haskell's referential transparency, consistency, mathematics-oriented culture, and heavy amount of abstraction encourage problem solving at a very high level. The fact that this is all built upon little other than function application means that not only is the thought process, but even concrete solutions are very transferable to any other language. In fact, in Haskell, it's quite common for a solution to simply be written as an interpreter that can then generate code in some other language. Many other languages employ language-specific features, or work around a lack of features with heavy-handed design patterns that discourage abstraction, meaning that a lot of what is learned, and a lot of code that is needed to solve a particular problem just isn't very applicable to any other language's ecosystem. See More

Top Con

Package manager is unstable & lacking features

Cabal (There are other choices but this is the most popular) can not uninstall a package. Also working at a few locations it is difficult to have the same environment for each one be the same. See More

Top Pro

Mathematical consistency

As Haskell lends itself exceedingly well to abstraction, and borrows heavily from the culture of pure mathematics, it means that a lot more code conforms to very high-level abstractions. You can expect code from vastly different libraries to follow the same rules, and to be incredibly self-consistent. It's not uncommon to find that a parser library works the same way as a string library, which works the same way as a window manager library. This often means that getting familiar and productive with new libraries is often much easier than in other languages. See More

Top Con

You have to learn more than just FP

Haskell is not only a functional language but also a lazy, and statically typed one. Not only that but it's almost necessary to learn about monads before you can do anything useful. See More

Top Pro

Referentially transparent

Haskell's Purely Functional approach means that code is referentially transparent. This means that to read a function, one only needs to know its arguments. Code works the same way that expressions work in Algebra class. There's no need to read the whole source code to determine if there's some subtle reference to some mutable state, and no worries about someone writing a "getter" that also mutates the object it's called on. Functions are all directly testable in the REPL, and there's no need to remember to call methods in a certain order to properly initialize an object. No breakage of encapsulation, and no leaky abstractions. See More

Top Con

Symbols everywhere

Haskell allows users to define their own infix operators, even with their own precedence. The result is that some code is filled with foreign looking operators that are assumed to be special-case syntax. Even for programmers who know they're just functions, operators that change infix precedence can potentially break expectations of how an expression is evaluated, if not used with care. See More

Top Pro

Hand-writeable concise syntax

Conciseness of Haskell lets us to write the expression on the whiteboard or paper and discuss with others easily. This is a strong benefit to learn FP over other languages. See More

Top Con

Obscure ugly notation

0 = 1 Using "=" like this: <code> -- Using recursion (with pattern matching) factorial 0 = 1 factorial n = n * factorial (n - 1) </code> Example from https://en.wikipedia.org/wiki/Haskell_(programming_language) is quite simply annoying aesthetics. See More

Top Pro

Very few language constructs

The base language relies primarily on function application, with a very small amount of special-case syntax. Once you know the rules for function application, you know most of the language. See More

Top Con

Documentation for most packages is short and lacking

A few Haskell packages are well documented but this is the exception, not the rule. Most of the time a list of function signatures is what passes for documentation. See More

Top Pro

Quick feedback

It's often said that, in Haskell, if it compiles, it works. This short feedback loop can speed up learning process, by making it clear exactly when and where mistakes are made. See More

Top Con

Too academic, hard to find "real world" code examples

Top Pro

Functions curry automatically

Every function that expects more than one arguments is basically a function that returns a partially applied function. This is well-suited to function composition, elegance, and concision. See More

Top Con

You need some time to start seeing results

Haskell's static typing, while helpful when building a project, can be positively frustrating for beginners. Quick feedback for errors means delaying the dopamine hit of code actually running. While in some languages, a beginner's first experience may be their code printing "Hello World" and then crashing, in Haskell, similar code would more likely be met with an incomprehensible type error. See More

Top Pro

Easy to read

Haskell is a very terse language, particularly due to its type inference. This means there's nothing to distract from the intent of the code, making it very readable. This is in sharp contrast to languages like Java, where skimming code requires learning which details can be ignored. Haskell's terseness also lends itself to very clear inline examples in textbooks, and makes it a pleasure to read through code even on a cellphone screen. See More

Top Con

Lazily evaluated

Haskell's lazy evaluation implies a level of indirection - you're not passing a value, you're passing a thunk. This is often difficult to grasp not just for beginners, but for experienced programmers coming from strictly evaluated languages. This also means that, since for many, strict evaluation is their first instinct, initial expectations of a function's performance and complexity are often broken. See More

Top Pro

Popular in teaching

Haskell is really popular in universities and academia as a tool to teach programming. A lot of books for people who don't know programming are written around Haskell. This means that there are a lot of resources for beginners in programming with which to learn Haskell and functional programming concepts. See More

Top Con

Only pure functional programming

Not proper functional programming but a subset of the style called pure functional programming. See More

Top Pro

Easy syntax for people with a STEM degree

Since the basic syntax is very similar to mathematics, Haskell syntax should be easy for people who have taken higher math courses since they would be used to the symbols used in maths. See More

Top Con

Curried type signatures obfuscate what were the in and out types originally

Top Pro

Powerful categorical abstractions

Makes categorical higher order abstractions easy to use and natural to the language. See More

See All

score 69 · Answer 2

Elm

Top Pro

Compile errors are human-friendly

A lot of thought has gone into making the user experience of encountering compile errors as delightful as possible. See more info at http://elm-lang.org/blog/compiler-errors-for-humans. See More

Top Con

Missing syntactic sugar ('where' clauses, pattern guards)

Elm is missing a lot of syntactic sugar that Haskellers may consider core, such as 'do' notation, 'where' clauses, pattern guards, and operator sections. See More

joseph stevens's Experience

6 months, after two years of F# with limited progress in learning functional programming, elm taught me in two months. Elm is simple on purpose, and pure. See More

Specs

Current stable version:0.19.1

Platforms:Windows Linux Mac Web

GZipped size:23.2 kB

Top Pro

The Elm architecture offers a simple pattern for all programs

What could be nicer when creating a program than being able to follow a simple, reusable recipe: model (represent your domain), action (progress your story), view (show it). See More

Top Con

No Genericness in the future

Currently there is no code genericness like typeclasses possible, it has been officially stated that this will never change. See More

mailinator's Experience

much better than trying to make javascript do functional code See More

Top Pro

Easier to make front ends than JS

This is perhaps subjective but I think it holds pretty true. See More

Top Con

Code Repetition

Because of the lack of genericness Elm needs a lot of code to be repeated. There are 130+ implementations of map in Elm's core libraries. See More

Top Pro

Avoids advanced FP topics such as Monads

This is a great boon to people that want to learn FP but aren't ready for a deep dive into category theory and a bunch of other things. See More

Top Con

Issues are swept under the rug

Controversies and criticism is ignored and actively hidden from the community. Breaking changes in new versions are not officially documented (e.g. removal of Native Modules, Name Shadowing, 4+ Elements Tuples and custom operators do not appear in the official announcement for Elm 0.19) to avoid discussion. See More

Top Pro

Growing community

Elm is gaining popularity, somewhat faster than many of the other solutions here. This translates to more code examples, more documentation, and more libraries. See More

Top Con

Updates break existing code often

The last few updates of Elm broke existing code in major ways. See More

Top Pro

No run-time exceptions

Lack of run-time exceptions makes it easy to produce large swathes of reliable front-end code without drowning in tests. See More

Top Con

Good for beginners, not good for experts

Development in Elm is quite nice until you need some more advanced features. These however are actively discontinued and removed because Elm wants to establish a "single way of doing things" philosophy. See More

Top Pro

Good tooling

All major editors have great support. With Atom for example, Elm plugins are available for linting, formatting, make/compiler support and Elmjutsu will simply overflow you with super useful functions, like navigate to referenced definition and show expression type. See More

Top Con

Community harsh if criticised

If one even dares to start a discussion about a feature on Elms Slack, Discord, Subreddit or Github one will be aggressively shut down often arguing that one should use purescript instead. See More

Top Pro

Inferred static typing

ML static typing is great because it's always there, you just choose how explicit you want to be and how much you want the compiler to do. See More

Top Con

Features get removed without warning

Often features that are deemed to be misused by the community like infix operators get removed without much of a warning. See More

Top Pro

Super easy refactoring with very helpful compiler errors

In no other language you can refactor so easy without any worries, since the compiler will guide you through. It is like TDD but more compiler-error driven. See More

Top Con

Limited js interop

Only one way ports are available as a crude js FFI. This means you can only call functions both directions but will not get a result. See More

Top Pro

Great and simple way to learn Purely Functional Programming

You can try to apply some functional programming ideas in other languages that have an imperative basis, but you haven't seen the real power unless you tried it in the environment of purely functional programming. Elm is a simple language with great learning resources and easy graphical output, which makes it easy to explore the power of functional programming. Plus programming in Elm is very readable. See More

Top Con

Lack of typeclasses

Elm doesn't have typeclasses which means some code needs to be duplicated. A fix in a function that needs typeclasses means all of the duplicates need to be fixed too. See More

Top Pro

Missing syntactic sugar

Easy to learn, most functions have only one way, not 5 alternatives where you must study where to best use what. See More

Top Con

Not quite Haskell semantics

Elm is a strict language, semantically different from Haskell. Elm also borrows a lot from OCaml and F#. While this makes for a nice syntax, it does mean that, for the Haskell programmer, there may be some surprises when it comes to semantics or function names. See More

Top Pro

Simpler syntax than Haskell

For a beginner, Haskell's syntactic sugar just gets in the way. Elm's syntax is easier to learn. See More

Top Con

No higher-kinded types

This significantly limits Elm's abstraction power compared to Haskell. A generic type can be considered a function at the type level. A higher-kinded type is a higher-order function at the type level (higher-order functions are those that take function objects as arguments or return function objects as results). See More

Top Pro

Easy to code review

The lack of side-effects and simple, consistent language semantics make it easy to quickly review incoming changes. See More

Top Pro

Good documentation

Elm is gaining popularity, somewhat faster than many of the other solutions here. This translates to more code examples, more documentation, and more libraries. See More

Top Pro

Static module system

Elm uses easy to use modules. Use: import List import List as L import List exposing (..) import List exposing ( map, foldl ) import Maybe exposing ( Maybe ) import Maybe exposing ( Maybe(..) ) import Maybe exposing ( Maybe(Just) ) Creation: module MyModule exposing (foo, bar) See More

Top Pro

Designed around high-level front-end development

As Elm was designed as a front-end langauge, it has out of the box support for things like DOM-element creation, letting programmers focus on their application logic, rather than implementation details specific to the web. See More

Top Pro

Instant gratification with GUI's

The fact that it is a batteries-included front-end language means it is very easy to get something tangible on the screen, when compared to other functional languages. This makes it great at hooking a beginner into the style. See More

Top Pro

Batteries included

The Elm Architecture means you don't need to spend valuable time and effort choosing the right frameworks, state management libraries, or build tooling. It's all built in. See More

Top Pro

Reactive programming is baked in

Functional reactive programming has emerged as a good, straightforward means of modelling change over time. It is well suited to graphical environments. Elm was conceived with FRP in mind. See More

Top Pro

Higher confidence in code correctness and quality

Pure functions, immutable data structures, amazing compiler, clean and homologous syntax used for HTML, logic, and optionally to replace CSS, elimination of entire classes of bugs so you don't even need most unit tests. These factors lead to better code, better programs, higher confidence, and ultimately, more satisfaction. See More

Top Pro

Time-travelling debugger and Hot-swapping of code

Elms purity and high-level FRP primitives allow for similarly higher-level tools that other languages can only dream of. See More

Top Pro

Tailor-made for games

While it might not have been created as a game engine, it was created as a platform for rendering graphical UIs. Couple this with the simple Elm Architecture and you have a standalone platform that is ready for indie-game development. See More

Top Pro

High-level Functional-Reactive Code

Build animations, games, and interactions with an incredibly small amount of terse, readable code. See More

See All

score 78 · Answer 3

F#

Top Pro

Concise syntax

F#'s syntax tends to be terse while remaining very readable and easy to understand without being a chore to write. See More

Top Con

Has no ad-hoc polymorphism (á la Type Classes)

You have generics, you have interfaces, you have inheritance, you have a lot of things at your disposal but you don't have Type Clases. They can be emulated using some clever constructs but there's nothing like having the real thing. See More

Ernesto Barros's Experience

It looks so much like Elm and it works everywhere. With great community and very friendly Editor! If you like Elm then you ought to look at F# :-) They are so good at explaining new ideas. You will always be on the frontline of adopting new technologies!! Which is a big + to me!! See More

Specs

Current stable version:6.0

License:Apache 2.0

IDE Support:Visual Studio, Code, Rider

Top Pro

Easier transition from other paradigms

Since F# is not a purely functional language, it lends itself to being more easily picked up by programmers that have experience with other paradigms. See More

Top Con

Infested with OOP

Still relying on .NET OOP libraries. See More

Top Pro

.NET Interoperability

Since F# runs on the Common Language Runtime or CLR, it has access to the entire .NET Framework, as well as libraries written in other .NET languages such as C#, VB.NET, and C++/CLI. See More

Top Pro

Multiplatform, it runs on .Net Core

Forget Xamarin and Mono. F# now runs on the multiplatform .Net Core! See More

Top Pro

You can run F# in the browser

Thanks to a project like Fable, you can write and run your client app in F# and run it over JavaScript. It allows you to share code between your server and client. See More

Top Pro

Natively supported by Visual Studio

This is a .Net language natively supported by Visual Studio. Though it is not as tooled up as C# the support is still substantial. In particular, C# deployment scenarios can be enabled for it with small C# wrapper projects. Integration with Visual Studio provides: IntelliSense, debugging, projects an other features. See More

Top Pro

Allows writing predictable code

Like many other functional languages, F# takes a stance of immutability for most of its constructs (state, values etc...). There are several reasons why having immutable values is good. One of those is that the code you are writing becomes much more predictable and you don't have to worry about any side effects. See More

Top Pro

Fall into the pit of success

F# directs you into a workflow where the right way is the path of least resistance. Coming from a C# background, its restrictions might feel arbitrary at first (e.g., what do you mean my code has to be in dependency order!? Arbitrary alphabetical or bust!), but you'll soon realize that your code is cohesive, concise and consistent in a way that it never was before - and you can compile and run with confidence! See More

Top Pro

Type Providers

Top Pro

F# is supported by Xamarin

Thanks to Xamarin, F# is a functional language that you can use to build for iOS, Android and Windows. See More

See All

score 56 · Answer 4

Elixir

Top Pro

Great for concurrency

Leverages the existing Erlang BEAM VM See More

Top Con

Some design choices may seem strange

Some design choices could have been a little more appealing, for example: using "do...end" comes natural in Ruby for blocks but Elixir uses them for everything and it looks pretty weird: Enum.map [1, 2, 3], fn(x) -> x * 2 end or receive do {:hello, msg} -> msg {:world, msg} -> "won't match" end See More

Hilko's Experience

I've been a fan of functional programming for a long time, but either found the language I used a bit too daunting (Haskell, Clojure had me wrap my head around FP ánd Lisp), or too forgiving (JS offers too many anti-functional escape hatches, for example). Elixir was exactly the right amount of enforced FP combined with familiar and elegant syntax, and the advantages unique to a language on the BEAM VM were initially just gravy, and now a reason for me to stay within the ecosystem. See More

Specs

Current stable version:1.11.2

Site:https://elixir-lang.org

Price:Open source (Free)

GZipped size:3.61 MB (without required Erlang VM)

Top Pro

Great documentation

Elixir's documentation is very good. It covers everything and always helps solving any problem you may have. It's also always available from the terminal. See More

Top Con

Deployment is still not as easy as it should be

Top Pro

Great getting started tutorials

The tutorials are very clear and concise (even for a person not used to functional programming). Plus they are also very mobile friendly. See More

Top Pro

Syntax is similar to Ruby, making it familiar for people used to OOP

All of the benefits of Erlang; without as steep a learning curve of prolog based syntax. Elixir is heavily inspired by Ruby's syntax which many people love. See More

Top Pro

Full access to Erlang functions

You can call Erlang functions directly without any overhead: https://elixir-lang.org/getting-started/erlang-libraries.html See More

Top Pro

Powerful metaprogramming

Write code that writes code with Elixir macros. Macros make metaprogramming possible and define the language itself. See More

Top Pro

Scalability

Elixir programming is ideal for applications that have many users or are actively growing their audience. Elixir can easily cope with much traffic without extra costs for additional servers. More details can be found here. See More

Top Pro

Easy to download libraries

Comes with built in build tool called "mix". This will automatically download libraries and put them in the scope of the application when you add them to the "deps" function and run mix deps.get See More

Top Pro

Types don't get in the way

Gradual typing is a wonderful middle-ground for those who like dynamic languages but see the value of typing. See More

See All

score 18 · Answer 5

Idris

Top Pro

Full dependent types

Idris not only has support for type classes, but is a fully dependently typed language, giving you the full power to statically verify your code. See More

Top Con

The language is still under development

Top Pro

Domain driven design and type driven development

Because of full dependent types in Idris, the programmer can focus more on modelling the domain with types and waste less time fixing common bugs that the type checker will catch. Dependent types help apply type driven development and a lot of code auto generation, making the compiler and type checker an ally in developing working software instead of just getting in the way. See More

Top Con

Not widely used

Top Con

Different semantics from Haskell

Idris, while similar to Haskell, has strict semantics, which may cause some confusion if your backend is done in Haskell. If using Idris, it would make sense to do the backend in Idris as well, if not for the fact that Idris currently has fewer libraries available for web development than Haskell. See More

Top Con

Weaker type inference

As type inference is undecidable for dependently-typed languages, Idris cannot offer the full type inference that Haskell supports, and so more type annotations will be needed. See More

See All

score 28 · Answer 6

Racket

Top Pro

Realm of Racket is an excellent entry-level guidebook

Realm of Racket teaches the big-bang approach for managing world state. It does so by walking the reader through the development of small games. There are few guidebooks that are as useful and entertaining. See More

ArtisticSalacia's Experience

I used racket-lang to learn the most important aspects of functional programming. It comes with a real wealth of useful libraries for graphics, databases, mathematics, text processing etc. There is also a type system called typed racket which reflects modern views to functional programming. See More

Specs

Current stable version:8.5

Platforms:Linux, Windows, OSX

Site:https://racket-lang.org

Price:Free

See All Specs

Top Pro

Racket was designed to teach functional programming from the start

Racket is based on Scheme (LISP Family) and is very similar to Clojure. So there are a ton of (). The reason it is easier to learn is that it is not trying to be "Pure" if there is even such a thing in terms of Functional Programming. The great thing about Racket is it has everything included. You get DrRacket for developing programs. You want to add a picture to your software you can insert pictures. If you want to add libraries just open the package manager. The Syntax is an opinion but it really does feel easier to see what is happening since everything is in brackets) Racket is a really a Programming Language for making Programming Languages. So there are smaller syntax Racket called Student Racket which makes things easier to pick up. See More

Top Pro

Free resources to Learn

Includes several free online books and great documentation. See More

Top Pro

Great RPEL IDEA included Dr. Racket

Top Pro

Active community

Racket has an active community of users/developers that makes it easy to get help when needed. See More

Top Pro

Syntax fits to functional programming

Although syntax is different from that of mainstream languages, S-expressions are a perfect match to functional programming. See More

Top Pro

Subtly encourages functional programming

Racket makes it inconvenient to pursue imperative habits while encouraging functional programming by Lisps's syntax. For example, the syntax for defining a function is almost the exact same as defining a variable. In addition, Racket has a strong set of higher-order functions built in to the language. See More

Top Pro

Easily embeddable

Racket is famously embedded in the game engine underlying Naughty Dog's Uncharted and The Last of Us games, because it proved to be so easy to embed. See More

See All

score 84 · Answer 7

Clojure

Top 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. See More

Top 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). See More

LovelyPoseidon's Experience

It's a LISP See More

Specs

Current stable version:1.10.1

Platforms:Windows, Linux, Mac

Site:www.clojure.org

Price:Free, Open Source

See All Specs

Top 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. See More

Top 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. See More

Top 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: https://clojure.org/reference/lisps http://stackoverflow.com/q/6008313/2636454 http://gilesbowkett.blogspot.com/2015/01/one-major-difference-between-clojure.html http://softwareengineering.stackexchange.com/q/153128/166211 See More

Top 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. See More

Top 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. See More

Top 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. See More

Top 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. See More

Top Pro

Rich Hickey

The creator is so awesome, he's a feature. Just look up his talks and see why. See More

Top Pro

Dynamic language

A superb data processing language. While rich type and specification systems are available they are optional. See More

Top Pro

Extensible

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). See More

Top 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. See More

Top Pro

No C/Java syntax

Refreshing, BTW! See More

Top 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. See More

See All

score 23 · Answer 8

Scheme

Top Pro

Great, well known textbooks available

There is a set of very strong textbooks introducing CS and programming using Scheme. These books are available for free online. The most famous example--and one of the most famous CS books full stop--is Structure and Interpretation of Computer Programs usually known as SICP. This book introduces fundamental ideas in computer science and covers an incredible amount of material quickly and clearly without requiring any prior knowledge. However, some people find SICP a bit challenging as a first text. Happily, there are other more introductory texts as well. Simply Scheme is a book designed to be read before SICP, easing beginners into the language as well as CS and programming in general. How to Design Programs is another text used in introductory college courses. See More

Top Con

Fragmented ecosystem

Scheme is an IEEE standard, not an implementation. Unfortunately, the standard is too minimal and practical implementations have diverged--they had to expand on the standard to get anything done, but did so in incompatible ways. The later de facto standard R6RS tried to correct this, but lost Scheme's minimalist elegance in the process. The newer R7RS standard takes the best of both worlds with an elegant minimalist core and a practical standard library. See More

Top Pro

Simple syntax

Scheme syntax is extremely regular and easy to pick up. A formal specification of the syntax fits onto just a few pages; it can be introduced informally in a paragraph or two. Students are not distracted by remembering how to write if statements or loops or even operator precedence because every syntactic follows the same pattern. Ultimately, everything looks something like this: (func a b c) This includes not only user-defined functions but even control flow: (if cond then-clause else-clause) or even primitive operations like define and set: (define foo 10) (set! foo 11) This means that nothing really has special syntactic treatment in the language. There are essentially no weird edge-cases to memorize, and different concepts are given a more equal weight in the language. (Unlike Algol-like languages which tend to given undue weight to loops and assignment statements, for example.) See More

Top Con

Not purely functional

Scheme is a multi-paradigm language including metaprogramming and procedural elements alongside functional elements. As such it will not give a clear impression of a purely functional language. See More

Top Pro

Great at teaching fundamental programming ideas

Scheme teaches the important, fundamental ideas immediately without the distraction of unnecessary syntax or language features. See More

Top Con

A language that is purely academic

If someone said "I am starting a project in Scheme" then they are either talking about their homework or they are starting a joke. See More

Top Pro

No Magic - it's clear how everything works

Scheme has far less built into the language itself, helping students see that things like OOP are not magical: they are just patterns for organizing code. Everything in Scheme is built up from a very small set of primitives which compose in a natural and intuitive fashion. Having a language that does not accord many things special status helps keep students open minded. This will help students later go between different languages and paradigms from procedural to object-oriented to functional. See More

Top Con

Tight Job Market

There are little to none jobs searching for a Scheme programmer. The ones that exist are more related to Research in Maths or Artificial Intelligence. See More

Top Pro

Multiparadigm

Unlike most languages, Scheme actually accords both functional programming and imperative programming roughly equal status. Many other languages like Python and Java are staunchly imperative while SML and Haskell are primarily functional; Scheme is a nice middle ground. Additionally, since Scheme syntax is extremely flexible, it can easily be re-purposed for teaching non-deterministic and logic programming. There is no need to learn a new language like Prolog when the same ideas can easily be expressed with Scheme syntax. This gives students a good perspective on different ways to think about and organize programs, which makes it much easier to move forward to other languages and technologies. See More

Top Pro

Great, well known textbooks

There is a set of very strong textbooks introducing CS and programming using Scheme. These books are available for free online. The most famous example--and one of the most famous CS books --is Structure and Interpretation of Computer Programs usually known as SICP. This book introduces fundamental ideas in computer science and covers an incredible amount of material quickly and clearly without requiring any prior knowledge. However, some people find SICP a bit challenging as a first text. Happily, there are other more introductory texts as well. Simply Scheme is a book designed to be read before SICP, easing beginners into the language as well as CS and programming in general. How to Design Programs is another text used in introductory college courses. See More

Top Pro

Robust metaprogramming

The quotation functionality of Lisp allow for extremely powerful, yet syntactically straightforward metaprogramming via macros. This is more powerful than the C preprocessor while being less involved than something like Template Haskell or F# quotations. Using macros to properly decompose a problem domain teaches new developers good habits, improving composibility and reliability when tackling large programs. Scheme metaprogramming also serves as a gentle introduction to domain specific languages. See More

Top Pro

Many different implementations for different domains

There are around 30 different implementations of the most recent Scheme standard (R7RS), optimized for different domains - from embedded systems over native compilation, desktop programs, web services and the JVM up to targeting Javascript in Browsers. See More

Top Pro

Multi platform

GNU/Linux, OS X, and Windows versions available. See More

Top Pro

Easy flow follow up

Since the syntax is easy and it's clear how everything works, it's easy to see how the program is running. See More

Top Pro

Definition of functional language

Part of the family of languages that started the concept. Pure functional programming is a subset of functional programming and should not be confused with functional programming proper. See More

See All

score 29 · Answer 9

OCaml

Top Pro

Encourages functional style

It steers you towards a functional style, but doesn't bother you with purity and "monads everywhere" like other languages, such as Haskell. See More

Top Con

Strong focus on *nix systems, lacking native support for MS Windows

Lacks native support for Windows systems. See More

PracticalDekla's Experience

pragmatic functional programming. See More

Specs

Current stable version:4.0.7

Site:http://ocaml.org

Price:Open source (Free)

License:LGPL version 2.1

See All Specs

Top Pro

No windows!

Strong focus on *nix systems, lacking native support for MS Windows Lacks native support for Windows systems. See More

AuthenticHlin's Experience

compiles to machine code, safe and productive See More

Top Pro

Actively-developed functional programming language at the forefront of research

Functional programming is based on the lambda calculus. OCaml is in its functional parts almost pure lambda calculus, in a very practical manner: useful for many daily programming tasks. The acitve development makes improvements to the type system like generalized algebraic data types (GADT) or polymorphic variants, so when learning this language you get at once a down to earth usable compiler and advanced abstraction features. See More

Top Pro

Sophisticated and easy-to-use package manager

OPAM is a package manager for OCaml, which is really easy to use, just like npm. It creates a .opam folder in home directory. The documentation is great as well, and you can switch between multiple versions of OCaml for each project. You can also package your project and publish it on OPAM repositories, even if the dependencies do not exists on OPAM. See More

Top Pro

One of the best for writing compilers

OCaml is compiled to native binary, so it's amazingly fast. Being a member of ML-family languages, it has expressive syntax for trees, and has great LLVM support. See More

Top Pro

Stable syntax

The syntax is consistent, some syntaxic sugar but at a reasonable level, so reading code of others isn't too much confusing. See More

Top Pro

Strong editor integration

The merlin editor tool provides all you need to develop OCaml in your favourite editor. See More

See All

score 9 · Answer 10

PureScript

Top Pro

Higher kinded types

Has Typeclasses and RankNTypes. See More

Top Con

Compiler could have better error messages

The compiler often gives a message that is not helpful. See More

Specs

Current stable version:0.15.4

Top Pro

High performance FFI code

The Eff monad, which is used for FFI code, optimizes out calls to bind, and supports tail call optimization, resulting in clean, efficient Javascript. The psc compiler also specifically recognizes the ST monad, and transforms scoped variables into mutable Javascript variables, for even more efficient code. See More

Top Con

Lack of good IDE/tooling support

Top Pro

Modules can be compiled to CommonJS

Modules compiled to CommonJS can be included with 'require', making it incredibly simple to call Purescript code from Javascript. See More

Top Con

Lots of dependencies needed to get started

Purescript is written in Haskell, but meant to be used with Node.js. As a result, to get started, users must install ghc, cabal, node.js, grunt, and bower. Purescript also has its own compiler, and different semantics form Haskell, and so even after installing, there's still some overhead to getting productive with Purescript. See More

Top Pro

Type safety

Compiling should be your first unit test. A tight type system (static and hopefully strong) will catch many logic errors that are often difficult to spot through debugging. In languages like PureScript, if it compiles, it often runs properly. See More

Top Pro

FFI

FFI system is quite good and easy to use. You can import functions curried or not curried. Records and arrays use native JS objects and arrays. See More

Top Pro

Has row polymorphism and extensible effects

Top Pro

Pure functional language

You cannot have side effects, unless a function is explicitly defined as so. See More

See All

score 16 · Answer 11

Erlang

Top Pro

Battle proven

Erlang has been used in production for more than 20 years now. During that time it has proven itself over and over again that works great in both small startups and large-scale enterprise systems. Erlang has been used extensively by Ericsson themselves. For example, the AXD301 ATM, which is one of Ericsson's flagships is probably the largest Erlang project ever with more than 1.1 million lines of Erlang code. See More

Top Con

Strange syntax

Erlang's syntax may feel very strange to 99% of programmers who have never used it. This is because it does not share any similarities or common syntax definitions that are found in all the other languages that are used today. See More

Deuxis's Experience

To quote Evan Miller, "The good news about Erlang can be summed up at this: Erlang is the culmination of twenty-five years of correct design decisions in the language and platform. Whenever I've wondered about how something in Erlang works, I have never been disappointed in the answer. I almost always leave with the impression that the designers did the “right thing”. I suppose this is in contrast to Java, which does the pedantic thing, Perl, which does the kludgy thing, Ruby, which has two independent implementations of the wrong thing, and C, which doesn't do anything." See More

Top Pro

Great for writing distributed applications

Erlang is made to be parallel and distributed. Because it's very easy to write code that uses multiple processor cores, it's also very easy to write applications that span multiple servers. See More

Top Con

Useful in only one niche

Erlang is not really a general purpose language. It has a very special and well-defined niche where it towers above everything else. It's specialized in scalability and in distributed applications. Which is not necessarily a bad thing per se, but it still lacks and falls behind other languages when it needs to do things outside it's niche. See More

Top Pro

Fault-tolerant

Fault tolerance means that a system has the property to continue operating even though one or more components have failed. For Erlang systems, this means that the system is kept running even if for example a user has to drop a phone call rather than forcing everyone else to do so. In order to achieve this, Erlang's VM gives you: Knowledge of when a process died and why that happened The ability to force processes to die together if they depend on each other and if one of them has a fault. A logger that logs every uncaught exception Nodes that can be monitored so that you find out when they go down The ability to restart failed processes (or groups of them) See More

Top Pro

Upgrade code without stopping the system

In a real-time system it may not be possible to stop the system in order to implement code upgrades. For these cases Erlang gives you dynamic code upgrade support for free when using OTP. The mechanism is very easy to understand and works as follows: Start the app Edit the code Recompile That's all that is needed, the app updates with the new code while it's still running and tests are run automatically. See More

Top Pro

Built from the ground up with concurrency and distributed computing in mind

Erlang has strong roots with the telecom industry in which concurrent processes are normal. It's designed to be concurrent, to be used for distributed computing and to be scalable. See More

Top Pro

Consistency across platforms

Erlang's processes run in a complete independent way from the OS (they aren't managed by the OS scheduler neither). This means that programs written in Erlang will run exactly the same way regardless of the operating system or platform. See More

Top Pro

Little overhead

Erlang's processes have very little overhead (about 500 bytes per process). This means that a huge amount of processes can be created, even on older machines. See More

Top Pro

Designed to be intuitive

Erlang's eccentric syntax and features were created to be natural for humans, not just for programmers used to the C style. Functions (or rather, all blocks/statements) are structured like sentences, with commas separating the instructions, semicolons separating overloads of the same function and a period marking the end. Dynamic but strong typing means that types are no concern but there are no weird implicit conversions. Destructuring operations are the standard. The ultra-light and easy to manage processes communicating via messages are basically the dream of anyone wanting to touch concurrency. There is even an entire section of the language dedicated to parsing and constructing binary blobs in an intuitive way. See More

See All

score 8 · Answer 12

Ceylon

Top Pro

Excellent type system

Intersection and union types make expressing some concepts very easy and intuitive See More

Top Con

Although it supports functional programming, it's above all an object oriented language

Specs

Current stable version:1.3.2

Top Pro

Regular syntax

Makes it very easy to parse and read code See More

Top Pro

Local type inference

Removes a lot of boilerplate See More

Top Pro

Great support for processing lazy streams

Ceylon has great support for processing lazy streams using higher order functions and comprehensions. See More

See All

score 7 · Answer 13

Rust

Top Pro

Great documentation

Rust has an official documentation and tutorial and tools for generating docs for libraries See More

Top Con

Low-level programming language

This means that it encourages the programmer to be very careful in terms of how memory is allocated, etc. Most applications can run without exceeding the capacity of the server, even with an inefficient dynamic scripting language. See More

ImpartialNannaNepsdottir's Experience

Best See More

Specs

Current stable version:1.4.0

Platforms:Linux, MacOS X, Windows, BSD

License:MIT/Apache

Top Pro

Generics support

You don't have to write same array and dictionary classes hundreds and thousands times for strong type check by compiler. See More

Top Con

Significant time required to understand the language fully

There's the infamous borrow checker for example. See More

Top Pro

Catch errors at compile-time

Since Rust is statically typed, you can catch multiple errors during compile time. This is extremely helpful with debugging, especially compared with dynamically typed languages that may fail silently during runtime. See More

Top Pro

Built-in concurrency

Rust has built-in support for concurrency. See More

Top Pro

Compiles to machine code allowing for extra efficiency

Rust uses LLVM as a backend, among other things this allows Rust code to compile down to machine languages. This allows developers to write programs that run as efficiently as possible. See More

Top Pro

Threads without data races

Unique ownership system guarantees a mutable data to be owned and mutated by only one thread at a time, so there's no data race, and this guarantee is checked at compile time statically. Which means easy multi-threading. Of course, immutable data can be shared among multiple threads freely. See More

Top Pro

Support for macros

When you identify a part of your code which gets repeated often, which you cannot abstract using functions or classes, you can use Rust's built-in Macros. See More

Top Pro

Makes developers write optimal code

Rust is a modern programming language written around systems. It was designed from the ground up this way. It's language design makes developers write optimal code almost all the time, meaning you don't have to fully know and understand the compiler's source code in order to optimize your program. Furthermore, Rust does not copy from memory unnecessarily, to give an example: all types move by default and not copy. Even references to types do not copy by default. In other words, setting a reference to another reference destroys the original one unless it's stated otherwise. See More

Top Pro

Official package manager and build tool

Cargo is the official package manager for Rust. It comes with the language and downloads dependencies, compiles packages, and makes and uploads distributable packages. See More

Top Pro

Big community

The biggest community contributing to language. See More

Top Pro

Easy to write understandable code

While not as verbose as Java, it still is much more verbose than languages like Go and Python. This means that the code is very explicit and easy to understand. See More

Top Pro

Functional programming

Very easy to create functional with some additional from structure application. See More

Top Pro

Supports cross compilation for different architectures

Since Rust 1.8 you can install additional versions of the standard library for different targets using rustup/multirust. For example: $ rustup target add x86_64-unknown-linux-musl Which then allows for: $ cargo build --target x86_64-unknown-linux-musl See More

See All

score 40 · Answer 14

Scala

Top Con

Limited type inference

Compared to other languages with type inference, such as Haskell, Scala's implementation is quite limited See More

Top Pro

Compiles to JVM bytecode, making applications written in Scala cross-platform

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. See More

Specs

Current stable version:2.13.1

Site:scala-lang.org

Price:Open Source (Free)

Top 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. See More

Top Pro

Supports both Functional and OOP paradigms

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. See More

Top Con

Way too complex for beginners

Even for seasoned programmers it's a difficult language. See More

Top Pro

Powerful static type system

It make easy to create complex abstractions and statically guarantee the safety of your program See More

Top Con

All the object-oriented constructs distract from learning functional programming concepts

It's not a "functional only" or even a "functional first" language. It 's very heavily object-oriented and all the functional concepts are implemented via OOP constructs or have to be implemented by the programming via those OOP construct (patterns). This makes it way more confusing to learn the functional programming concepts. See More

Top Pro

Great for concurrency

The immutable values make it perfect for working with concurrency. See More

Top Con

Static type system inherits cruft from Java

The type system is too complicated yet still less powerful than Haskell's. See More

Top Pro

Great REPL

It makes it easy to practice or test code. See More

Top Pro

Very good online courses

On coursera you can find great introduction to Scala by Martin Odersky. See More

Top Pro

Expressive functional programming abstraction for reusable and safe code

Top Pro

Type inference leads to a simpler syntax

Top Pro

Multiparadigm

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. See More

Top Pro

Offers 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. See More

See All

score 15 · Answer 15

Kotlin

Top Pro

Great tooling support

Since Kotlin is made by Jetbrains (the developers of IntelliJ IDEA) so it stands to reason that the IntelliJ support for Kotlin is also great. Besides that, Kotlin also works well with existing Java tools such as Eclipse, Maven, Gradle, Android Studio, etc... See More

Top Con

May be hard for programmers already used to imperative style to learn functional programming from Kotlin

Since Kotlin does not enforce any particular paradigms and is not purely functional, it can be pretty easy to fall back to imperative programming habits if a programmer comes from an imperative background. See More

Specs

Current stable version:1.3

Top Pro

Easy adoption for existing Java programmers

Kotlin runs on the JVM and Java interoperability has been one of the main objectives since the language was born. It runs everywhere Java does; web servers, mobile devices (Android), and desktop applications. It also works with all the major tools in the Java ecosystem like Eclipse, IntelliJ, Maven, Ant, Gradle, Spring Boot, etc. All of this makes adoption extremely easy even for existing Java projects. On top of this there's also ensured Type safety and less boilerplate code needed. See More

Top Con

The need for Java interoperability has forced some limitations

The need to make Kotlin interoperable with Java has caused some unintuitive limitations to the language design. See More

Top Pro

Easy to learn if you have prior programming experience

Kotlin's syntax is extremely easy to understand. The language can be picked up in a few hours just by reading the language reference. See More

Top Pro

No runtime overhead

The standard library is relatively small and tight. It mostly consists of focused extensions of the Java standard library and as such adds no additional runtime overhead to existing Java projects. See More

Top Pro

Officially supported for Android development

Starting with version 3.0 of Android Studio, Kotlin support will be built-in. This means that it's now easier than ever to use Kotlin for existing Android projects or even start writing Android apps only with Kotlin from scratch. This also means that Kotlin and Kotlin plugins for Android Studio will be fully supported in the future and their likelihood of being abandoned is quite small since Google is fully embracing the language for their Android ecosystem (alongside Java and C++). See More

Top Pro

Low-risk adoption for existing Java codebases

Since it has such a good interoperability with Java, Java libraries, and Java tools. It can be adopted for an existing Java codebase at little to no cost. The codebase can be converted from Java to Kotlin little by little without ever disrupting the functionality of the application itself. See More

Top Pro

Does not impose a particular philosophy of programming

It's not overly OOP like Java and it does not enforce strict functional paradigms either. See More

Top Pro

Is built to solve industrial problems

Kotlin has been designed and built by developers who have an industrial background and not an academic one. As such, it tries to solve issues mostly found in industrial settings. For example, the Kotlin type system helps developers avoid null pointer exceptions. Reasearch languages usually do not have null at all, but APIs and large codebases usually need null. See More

See All

score 8 · Answer 16

Standard ML

Top Pro

Powerful module system

The module system that Standard ML uses gives the programmer the power to define custom data types whose internal implementation is invisible to other programmers using the module. See More

Top Con

Not very popular outside academia

SML is mostly used in academia and doesn't have many uses in industry. While it's a good language for learning functional programming concepts, the language itself won't be very useful. See More

Top Pro

Implementing laziness is trivial

Since mutability is only confined to a special type of reference cells, implementing laziness in SML can be done in only 20 lines of code. See More

Top Pro

Enforces distinction between data and computations

Since it uses strict evaluation, it enforces distinction between data and computations which in turn enables you to use induction on algebraic data types as a reasoning principle. See More

Top Pro

Great exception system

Secret messages can be sent across distant parts of a program without possibility of being intercepted by unintended recipients in the middle. See More

See All

score 6 · Answer 17

JavaScript

Top Pro

Required for web development

If you are looking to create web projects, you will have to learn Javascript in order to develop the client side code. If you learn the foundations of programming in JavaScript you can reapply that education later in building web applications. See More

Top Con

Many errors pass silently

JavaScript looks for every possible way to treat the code you write as runnable and is very reluctant to point out likely errors. For example, you have call a function with too many arguments, the extra arguments are simply discarded. See More

Specs

Engine:V8/ChakraCore

Author:Ryan Dahl/Joyent

Version(LTS):8.x

Version(Latest):12.x

See All Specs

Top Pro

Prototype based Object Oriented System

Being object oriented, it supports the predominate and powerful programming approach. Being prototype based, it provides an intuitive approach to OOP. Whereas other popular languages use classes, which focus on thinking in the abstract, Javascript's prototypes allow you to focus on thinking in the concrete. For example, in a prototypical language, you think of a rectangle, and define it. You now have a rectangle. Let's say you want a red rectangle, you copy the rectangle and give it the property red. Want a blue one? Copy rectangle again give it a blue. Big blue rectangle? Copy blue rectangle and make it big. In a class-based language, first you describe a rectangle, describe a red rectangle as a type of rectangle, describe blue and big blue rectangles, and now that you have described them, you must create instances of them, and only then do you have the rectangles. Essentially: Classes are factories for objects, prototypes are objects themselves, and the latter method was created to be more intuitive, which is particularly advantageous to beginners. See More

Top Con

Easy to accidentally use globals

If you forget a var or new, you can clobber the global scope. For tiny scripts (JavaScript's original use case) globals are great, but for larger applications globals are generally regarded as a Bad Thing. This is because changes to one small part of a program can randomly break things anywhere else. These kinds of bugs are notoriously hard to find. See More

Top Pro

Speed (most implementations)

JS/ES is in the running for the fastest interpreted language given the optimizations and JIT integration of popular implementations. On the other hand, it fails utterly when compared with compiled (to native or VM code) languages. See More

Top Con

Each browser has its own quirks when executing the same code in some cases

Beginner programmers often make the mistake of coding something, seeing it works in the browser they tested it in, and then scratching their heads when it doesn't work in another browser. Ideally you'd want a language that works consistently across all platforms in order to be able to focus more on the programming and less on the underlying environment. It just takes time away from learning and forces you to spend time figuring out why this worked in browser X but not browser Y. See More

Top Pro

Atwood's Law "Any application that can be written in JavaScript, will eventually be written in JavaScript."

May also be a con. See More

Top Con

Complex

JavaScript has a long litany of warts and gotchas. JavaScript will bite you if you're just a wee bit careless. You have to exercise a great deal of caution and awareness. You either have to know the entire 545-page ES6 spec to avoid them all, or use a linter to help restrict you from using the bad parts (and you still have to be familiar with the language), but beginners don't know these things. (Linters are also prone to time-wasting false positives.) This is a significant cognitive burden on even the experienced programmer (as if coding wasn’t hard enough already), but try learning to program in the first place on top of all of this and you'll understand that JavaScript is a terrible choice for the beginner. See More

Top Pro

Great tools for development

Flow, JSHint/ESLint, Babel, npm, etc. See More

Top Con

The language itself is not very appealing to developers

JS is one of the most dreaded languages as it was designed for the purpose of becoming just an scripting language for a browser. It was never intended to take over as the leading technology in web development, thus the language has been streched past its own capabilities. A beginer should learn something else first, something that is better conceived and refined. See More

Top Pro

Complete dev stack can be run online

With codepen.io and other prototyping tools, you can learn Javascript from a mobile device. You don't even need a computer. It can be learned from an internet cafe or public library. See More

Top Con

Many tutorials, code, and resources, are structured for older ES5 code

Top Pro

Instant gratification

While it's easy to argue that Python will give you instant gratification, JavaScript is far better in this regard. Make a small change to a page and it's immediately visible in the browser. You can throw in a JavaScript library like jQuery with minimal fuss. See More

Top Con

Easy to fall into bad manners and bad mind structure

It wouldn't consolidate a good mind structure for moving to other languages. Too open. See More

Top Pro

C-like syntax

After learning Javascript, you will feel at home in other languages as C-like syntax is very common. See More

Top Pro

JSON is native to JS

JSON is arguably a "must-learn". With JS, that's one less additional syntax to learn. See More

Top Pro

Massive ecosystem

JavaScript has one of the largest programming ecosystems, as shown by the being the most popular language for projects on GitHub. As there are so many projects written in JavaScript there are lots of libraries available to build off of and many of them are written to be easy to use and integrate into other projects. There are also lots of resources available for learning JavaScript. Other than traditional tutorials, language learning sites such as Codecademy have JavaScript courses. The Mozilla Developer Database also serves as a great resource for learning about the standard libraries built into JavaScript. See More

Top Pro

First-class functions with lexical closures

While certainly not the only language with these features, this pro alone is so powerful that it compensates for most of JavaScript's problems. You'll learn to use closures and higher-order functions well in JavaScript, because you have to. And then you can generalize this knowledge to any other language that has these, and the good ones do. See More

Top Pro

Easy to build an application

By using the UI capabilities in HTML and CSS you can develop substantial applications with graphical interfaces more quickly and with less effort than in other languages which would require you to learn a windowing library. Building a useful application is one of the best ways to learn a new language and because of the low learning curve for creating applications you can create more substatial programs and learn more practical programming priciple faster. See More

Top Pro

Runs on both the browser and the server

With Node.js, it is now possible to run JavaScript as a web server. This would allow you to be able to create server based applications sooner than would if you had to learn a separate programming language as well for server side code. As JavaScript is the only language supported by web browsers it puts it in the unique situation of being the only programming language that's available on both the client side and server side. See More

Top Pro

No installation required

If you run a web browser you already have JavaScript installed and can get started right away. Modern browsers such as Chrome also have very powerful programming consoles built into them. Aside from the browser console, you can also use online Javascript playgrounds such as JS Bin and JS Fiddle. Even from a tablet. See More

Top Pro

Modern ESNext is far better than the JS of days past

Modern JS has made great strides, and can be targerted to older (or non-standard) browsers using Babel. There are new language constructs that can make programming in JS comfortable.; e.g.: async / await ( <3 ). See More

Top Pro

Very good debugger

Has a built in debugger with break points, watches that work on local values, and a console that you can use to edit anything at any time. Both in the browser (eg: Chrome), and server (eg: Nodejs). See More

Top Pro

Integrates very well with UE4

Coding an immersive 3D game can retain the attention of new programmers. ncsoft/Unreal.js. See More

Top Pro

Several Platforms to use the web stack and JS to create multi-platform apps

Opens the door to native application development as well as just websites. Use with React Native, Weex or Quasar (Vue), PhoneGap or Cordova, NativeScript... (etc) to build native apps. Use mostly the same code base for multi-platform and web. See More

Top Pro

One of the most underestimated languages

Deviously simple in syntax, yet highly powerful in paradigms, this language does not force you to the (actually intrinsically broken) object oriented paradigm, has a healthy dose of functional programming inside, and does not bloat the keyword space. Good javascript is all about structure. Bad javascript is all about lazy hipsters not taking the time to learn 'javascript, the good parts', a must read. See More

Top Pro

Can be very simple (teachable)

By setting a few ground-rules (effectively coding in a subset of JS), JS is one of the simplest languages to learn (requiring very few must-learn prerequisite concepts). See More

Top Pro

High demand for JavaScript developers

If you're looking for a career as a developer, JavaScript is the place to focus your attention. There is a huge demand for good developers especially in frameworks such as React and Angular. See More

See All

score 3 · Answer 18

Reason ML

Top Pro

Being able to access both JavaScript (NPM) and OCaml (Dune) ecosystems and packages

FerventSors's Experience

I came from a JavaScript/Java/Python (C-like) background and ReasonML really ease the scare of learning FP by being much syntactically C-like and having a very modern culture and tool chains. See More

Specs

Version:3.6.0

Top Pro

Easy development environment (e.g. Compiler, Editor tooling) setup

Top Pro

Uses established compiler technology from Ocaml with a tweaked syntax that leans more towards Javascript

See All

score 8 · Answer 19

Go

Top Pro

Simplified C-like syntax that is as easy to read and write as Python

The language is designed in a manner that seems logical. Syntax is simplified to reduce burden on the programmer and compiler developers. See More

Top Con

Hard to abstract even the simplest notions

Go is famously regarded as very simple. However, this simplicity becomes problematic in time. Programmers who use Go find themselves over and over again writing the same thing from a very low point of view. Domains not already served by libraries that are easy to glue are very difficult to get into. See More

Specs

Current stable version:1.18

Platforms:Windows, Linux, Mac etc.

GZipped size:115 MB (installer)

Developer:Google with Ken Thompson, Robert Griesemer, Rob Pike

Top Pro

Performance is on the order of C and Java

Go is blazing fast, but easier to write than Python, JS, Ruby, or many other dynamic languages. See More

Top Con

Implementation of interfaces are difficult to figure out

Finding out what interfaces are implemented by a struct requires a magic crystal ball. They are easy to write, but difficult to read and trawl through. See More

Top Pro

Syntax for exported code from a package is simplified to be less verbose than other languages

Any variable, type and function whose name begins with a capital letter will be exported by a project, while all other code remains private. There is no longer a need to signify that a piece of code is 'private' or 'public' manually. See More

Top Con

Designed to make the programmer expendable

Go was designed for large team projects where many contributors may be incompetent. That Go can still get things done under these conditions is a testament to its utility in this niche. Go's infamously weak abstraction power is thus a feature, not a bug, meant to prevent your teammates from doing too much damage. This also means any team member can be easily replaced by another code monkey at minimum cost. Good for the company, bad for you. The more talented programmers, on the other hand, will be very frustrated by having one hand tied behind their back. See More

Top Pro

Supports functional programming techniques such as function literals

This naturally also supports first class and high order functions, so you may pass functions as variables to other functions. See More

Top Pro

Supports splitting source code into multiple files

As long as every source code file in a directory has the same package name, the compiler will automatically concatenate all of the files together during the compilation process. See More

Top Pro

Multiple variables may be assigned on a single line

This conveniently eliminates the need to create temporary variables. Fibonacci example: x, y = y, x+y See More

Top Pro

Demonstrates a unique, simple concept to object-oriented programming

All types are essentially objects, be they type aliases or structs. The compiler automatically associates types to their methods at compile time. Those methods are automatically associated to all interfaces that match. This allows you to gain the benefits of multiple inheritance without glue code. As a result of the design, classes are rendered obsolete and the resulting style is easy to comprehend. See More

Top Pro

Automatically generates API documentation for installed packages

Godoc is provided to automatically generate API documentation for Go projects. Godoc also hosts its own self-contained web server that will list documentation for all installed packages in your Go path. See More

Top Pro

Supports 'modules' in the form of packages

Every Go source file contains a package line that indicates which package a file belongs to. If the name of the package is 'main', it indicates that this is a program that will be compiled into a binary. Otherwise, it will recognize that it is a package. See More

Top Pro

Great language for building networking services

Go was started as a systems language but now it has fully committed in the niche of networking services. This has been a brilliant move by Go because it allows them to capitalize on the immense talent of the Go engineering team (who are in the most part network engineers). In a world dominated by Java EE and slow scripting language, Go was a breath of fresh air and it continues to be one of the most powerful languages if you want to build networking services. See More

Top Pro

Programmers don't have to argue over what 10% subet of the language to implement in their software project

The language promotes programming in a specific idiomatic style, which helps keep every programmer on the same page. See More

Top Pro

Easy to install and configure; simple to compile software

Go software can be immediately installed, regardless of your operating system, package manager, or processor architecture with the go get command. Software is compiled statically by default so there is no need to worry about software dependencies on the client system. Makefiles and headers are no longer necessary, as the package system automatically resolves dependencies, downloads source code and compiles via a single command: go build. See More

Top Pro

Provides tools for automatically formatting code for your entire software project

This helps keep every programmer on the same page in a project and eliminates arguments over formatting styles. See More

Top Pro

The go compiler compiles binaries instantly — as fast as a scripting language interpreter

Compiled binaries are fast — about as fast in C in most cases. Compiles on every OS without effort — truly cross-platform compiler. As a result of the fast compilation speed, you can use the gorun program to use go source code as if it was a scripting language. See More

Top Pro

Built-in unit testing

The idiomatic approach to writing a Go software project is to perform test-driven development with unit testing. Every source code file should have an associated *_test.go file which tests functions in the code. See More

Top Pro

API documentation is rich in content; easy to memorize

Only features deemed critical are added to the language to prevent cruft from working its way into the language. The language is small enough to fit inside one's head without having to repeatedly open documentation. Documentation is hosted on an official webpage in a manner that is simple to read and understand. See More

Top Pro

Great team working behind it

Go has a solid team of engineers working on it (some of the best networking engineers in the world are working on Go). Up until now, the great engineering of the language has compensated for its lack of power. See More

Top Pro

Exceptionally simple and scalable multithreaded and concurrent programming

Goroutines are "lightweight threads" that runs on OS threads. They provide a simple way for concurrent operations — prepending a function with go will execute it concurrently. It utilizes channels for communication between goroutines which aids to prevent races and makes synchronizing execution effortless across goroutines. The maximum number of OS threads goroutines can run on may be defined at compile time with the GOMAXPROCS variable. See More

See All

score 13 · Answer 20

Python

Top Con

Not a fully functional language

Python is missing several features that make it fully functional, and has several design issues that make pure-functional programming a chore at best. The biggest of these is the limitations of lambdas and dysfunctional closure scoping. See More

Top Pro

Easy to use

Specs

Current stable version:3.9.1

Platforms:Windows, Linux, macOS, AIX, IBM i, iOS, z/OS, Solaris, VMS

GZipped size:22.5MB

Typing discipline:Dynamically typed

See All Specs

Top Con

Not designed for functional programming

Bare minimal list functions and no tail recursions. Biggest hangup is the imperative syntax which makes it difficult to make it have weak expressions. See More

Top Pro

Applications or web-based

Can be used in both OS and web-based environments very well. See More

Top Con

Slightly slower

When microseconds are involved and very high data throughput, python can respond slower than a base C/C++ application. But not very much. See More

Top Pro

Fast

Top Con

Inelegant and messy language design

The first impression given by well-chosen Python sample code is quite attractive. However, very soon a lack of unifying philosophy / theory behind the language starts to show more and more. This includes issues with OOP such as lack of consistency in the use of object methods vs. functions (e.g., is it x.sort() or sorted(x), or both for lists?), made worse by too many functions in global name space. Method names via mangling and the init(self) look and feel like features just bolted on an existing simpler language. See More

Top Pro

Can use both functional and object oriented paradigms

Python is not too functional and not too object oriented, so you can freely choose any paradigm when you see fit. See More

Top Con

Multiparadigm

While Python has powerful enough features to do functional programming, this is not required or even Pythonic (i.e. idiomatic for Python code). Unless you have a text or course specifically designed to teach the functional style in Python, learning Python really won't teach it. See More

Top Pro

Easy to get started

On top of the wealth of tutorials and documentation, and the fact that it ships with a sizeable standard library, Python also ships with both an IDE (Integrated Development Environment: A graphical environment for editing running and debugging your code); as well as a text-based live interpreter. Both help users to get started trying out code immediately, and give users immediate feedback that aids learning. See More

Top Con

Limited support for functional programming

While Python imports some very useful and elegant bits and pieces from FP (such as list comprehensions, higher-order functions such as map and filter), the language's support for FP falls short of the expectations raised by included features. For example, no tail call optimisation or proper lambdas. Referential transparency can be destroyed in unexpected ways even when it seems to be guaranteed. Function composition is not built into the core language. Etc. See More

Top Pro

Powerful full functional language

Top Con

Unflexible userbase

You will be expected to rigidly stick to the coding practices and to do everything by-the-numbers. See More

Top Pro

Lots of tutorials

Python's popularity and beginner friendliness has led to a wealth of tutorials and example code on the internet. This means that when beginners have questions, they're very likely to be able to find an answer on their own just by searching. This is an advantage over some languages that are not as popular or covered as in-depth by its users. See More

Top Con

Not good for mobile development

You can use frameworks like Kivy, but if your ultimate goal is to write mobile apps Python may not be the best first choice. See More

Top Pro

Good documentation

The Python community has put a lot of work into creating excellent documentation filled with plain english describing functionality. Contrast this with other languages, such as Java, where documentation often contains a dry enumeration of the API. As a random example, consider GUI toolkit documentation - the tkinter documentation reads almost like a blog article, answering questions such as 'How do I...', whereas Java's Swing documentation contains dry descriptions that effectively reiterate the implementation code. On top of this, most functions contain 'Doc Strings', which mean that documentation is often immediately available, without even the need to search the internet. See More

Top Con

Significant whitespace

While proper formatting is essential for any programmer, beginners often have trouble understanding the need and lack the discipline to do it. Add to that all those editors that randomly convert N spaces (usually 8) to tabs and you get an instant disaster. See More

Top Pro

Supports various programming paradigms

Python supports three 'styles' of programming: Procedural programming. Object orientated programming. Functional programming. All three styles can be seamlessly interchanged and can be learnt in harmony in Python rather than being forced into one point of view, which is helpful for easing confusion over the debate amongst programmers over which programming paradigm is best, as developers will get the chance to try all of them. See More

Top Con

Speed can matter

Python, like many interpreted and untyped languages, is fairly slow compared to compiled languages like C, C++ or Java. Sometimes this won't matter, but when it does you're talking about twenty times slower than C/C++ and ten times slowed than Java. You need to have a plan for what you will do if it is too slow. See More

Top Pro

Clear syntax

Python's syntax is very clear and readable, making it excellent for beginners. The lack of extra characters like semicolons and curly braces reduces distractions, letting beginners focus on the meaning of the code. Significant whitespace also means that all code is properly and consistently indented. The language also uses natural english words such as 'and' and 'or', meaning that beginners need to learn fewer obscure symbols. On top of this, Python's dynamic type system means that code isn't cluttered with type information, which would further distract beginners from what the code is doing. See More

Top Con

It is best suited for scripting, but so are many other languages

i.e. running js as a script in a node is trivial. Even languages that were not meant to run as a script are easy to use as a scripting language with just a .sh file. See More

Top Pro

It's really simple

It's very simple for understanding how programming works. If you don't like programming in Python, you probably won't like programming. It is a good way to find out with little investment. If you like, it is a great language. I wouldn't look for a language that has everything you eventually need to know in programming, such as static typing, in my first language. It should be easy to learn. You can pick up the hard stuff later if you tackle C or C++ or assembler. It will make learning them much easier. If you start with them, you might quit programming due to the difficulty of learning. See More

Top Con

Does not teach you about data types

Since Python is a dynamically typed language, you don't have to learn about data types if you start using Python as your first language. Data types being one of the most important concepts in programming. This also will cause trouble in the long run when you will have to (inevitably) learn and work with a statically typed language because you will be forced to learn the type system from scratch. See More

Top Pro

Has features of both high and low level language

It is somewhere between C and Java. See More

Top Con

Might not be very future-proof

Lots of features that will probably be crucial as time goes (good support for parallelism for example) are missing or are not that well-supported in Python. Since 2.x and 3.x still exist, be prepared to switch if something makes 3.x take off in the future. See More

Top Pro

Comes with extensive libraries

Python ships with a large standard library, including modules for everything from writing graphical applications, running servers, and doing unit testing. This means that beginners won't need to spend time searching for tools and libraries just to get started on their projects. See More

Top Con

Too opinionated for a general-purpose programming language

While it's a good language to learn and use after you have mastered a couple of other less rigid programming languages, it's definitely not good for first-time learners. Both the language itself and its community have made it quite clear that you should do everything the "Pythonic way" to get the best results, that it feels more like an opinionated framework instead of a general-purpose programming language, which means if you are a first-time learner and getting too "tuned" to the "Pythonic way" it will be much harder for you to learn other less-opinionated languages compared to the other way around. Like any programming languages and/or frameworks, I'd recommend first-time learners to learn less opinionated ones first to open up your mind, then learn some of the more opinionated ones to increase productivity for specific fields of works. After all, programming languages are just some utilities for the human mind to interface with the computers, and there are more suitable tools for different tasks, and you should master the "Pythonic way" (after you already have adequate experience in computer programming) instead of locking your mind too close to the "Pythonic way" as a first-time learner. See More

Top Pro

Has many libraries for scientific computing, data mining and machine learning

Python is commonly used in data science and has many libraries for scientific computing, such as numpy, pandas, matplotlib, etc. See More

Top Con

Multi-threading can introduce unwanted complexity

Although the principals of multi-threading in Python are good, the simplicity can be deceptive and multi-threaded applications are not always easy to create when multiple additional factors are accounted for. Multi-thread processes have to be explicitly created manually. See More

Top Pro

Very similar to pseudo-code

When learning Computer Science concepts such as algorithms and data structures, many texts use pseudo-code. Having a language such as Python whose syntax is very similar to pseudo-code is an obvious advantage that makes learning easier. See More

Top Con

Language fragmentation

A large subset of the Python community still uses / relies upon Python 2, which is considered a legacy implementation by the Python authors. Some libraries still have varying degrees of support depending on which version of Python you use. There are syntactical differences between the versions. See More

Top Pro

Includes pygame library

Want to start game development? No problem! Using pygame open-source library you can fast begin creating games without worrying about pointers or undefined behaviors which they exists in C/C++. See More

Top Con

Version Confusion with V2.x and V3.x

Top Pro

Good introduction to data structures

Python's built-in support and syntax for common collections such as lists, dictionaries, and sets, as well as supporting features like list comprehensions, foreach loops, map, filter, and others, makes their use much easier to get into for beginners. Python's support for Object Orient Programming, but with dynamic typing, also makes the topic of Data Structures much more accessible, as it takes the focus off of more tedious aspects, such as type casting and explicitly defined interfaces. Python's convention of only hiding methods through prefacing them with underscores further takes the focus off of details such as Access Modifiers common in languages such as Java and C++, allowing beginners to focus on the core concepts, without much worry for language specific implementation details. See More

Top Con

Abstraction to the point of hinderance

Python is abstracted far enough that if it's your first language, it will be harder to pick up lower level languages later versus going the other direction. See More

Top Pro

Best chances of earning most money

According to Quartz, Python programming skills on average earn $100,000 per year. Closely followed by Java, C++, JavaScript, C, and R with $90,000 per year and above. See More

Top Con

The process of shipping/distributing software is reatively complicated

Once you have you program the process of having a way to send it to others to use is fragile and fragmented. Python is still looking for the right solution for this with still differences in opinion. These differences are a huge counter to Python's mantra of "There should be one-- and preferably only one --obvious way to do it." See More

Top Pro

Interpreters for JS, Microtontrollers, .Net , Java & others

Python is not limited to just be cross platform. It goes far beyond all high level languages since it can run on top of several other frameworks & architectures : Examples of interpreters: Standard (PC Win/Lin/Mac, ARM, Raspberry, Smartphones): CPython usually, but some more specialized for smartphones: Kyvi, QPython, ... Web Browser JS : Brython, PyJS, .Net : IronPython Java: Jython Microcontrollers with WiFi like ESP8266 or ESP32: MicroPython Can be statically compiled (instead of interpreted) with Cython. (Do not mix up with cPython) With python, you're sure your code can run (almost) everywhere, from 2€ computers to the most expensives. So, for instance, with Jython you can access the Java libraries with Python language. See More

Top Con

Hard to debug other people's code

As the structure of Python code is based on conventions many developers are not following them and so it is difficult to follow/extract the design of not trivial application from the code. While this is a con, I see it in other languages as well. It seems to depend on the programmer. Most people don't learn conventions first, they just start programming. Unless you work for someone who insists you follow the conventions, you will probably go with what you like. You might never look at the conventions. See More

Top Pro

Advanced community projects

There are outstanding projects being actively developed in Python. Projects such as the following to name a random four: Django: a high-level Python Web framework that encourages rapid development and clean, pragmatic design. iPython: a rich architecture for interactive computing with shells, a notebook and which is embeddable as well as wrapping and able to wrap libraries written in other languages. Mercurial: a free, distributed source control management tool. It efficiently handles projects of any size and offers an easy and intuitive interface. PyPy: a fast, compliant alternative implementation of the Python language (2.7.3 and 3.2.3) with several advantages and distinct features including a Just-in-Time compiler for speed, reduced memory use, sandboxing, micro-threads for massive concurrency, ... When you move on from being a learner you can still stay with Python for those advanced tasks. See More

Top Pro

Static typing via mypy

Python's syntax supports optional type annotations for use with a third-party static type checker, which can catch a certain class of bugs at compile time. This also makes it easier for beginners to gradually transition to statically typed languages instead of wrestling with the compiler from the start. See More

Top Pro

Import Turtle

Do something visually interesting in minutes by using the turtle standard library package. Turtle graphics is a popular way for introducing programming to kids. It was part of the original Logo programming language developed by Wally Feurzig and Seymour Papert in 1966. Imagine a robotic turtle starting at (0, 0) in the x-y plane. After an import turtle, give it the command turtle.forward(15), and it moves (on-screen!) 15 pixels in the direction it is facing, drawing a line as it moves. Give it the command turtle.right(25), and it rotates in-place 25 degrees clockwise. Turtle can draw intricate shapes using programs that repeat simple moves. Example Turtle Star Drawing from turtle import * color('red', 'yellow') begin_fill() while True: forward(200) left(170) if abs(pos()) < 1: break end_fill() done() See More

Top Pro

Easy to find jobs

Python's popularity also means that it's commonly in use in production at many companies - it's even one of the primary languages in use at Google. Furthermore, as a concise scripting language, it's very commonly used for smaller tasks, as an alternative to shell scripts. Python was also designed to make it easy to interface with other languages such as C, and so it is often used as 'glue code' between components written in other languages. See More

Top Pro

Can be used in many domains

Python can be used across virtually all domains: scientific, network, games, graphics, animation, web development, machine learning, and data science. See More

Top Pro

One right way to do things

One of the Guiding Principles of Python is that there should be only one obvious way to do things. This is helpful for beginners because it means that there is likely a best answer for questions about how things should be done. See More

Top Pro

Active and helpful community

Python has an active and helpful community, such as the comp.lang.python Google Groups, StackOverflow, reddit, etc. See More

Top Pro

Cross-platform

Installs and works on every major operating systems if not already installed by default (Linux, macOS). See More

See All

28 Options Considered

My Recommendation for Haskell

My Recommendation for Haskell

Forces you to learn pure functional programming

Language extensions lead to unfamiliar code

Open source

Difficult learning curve

Highly transferable concepts

Package manager is unstable & lacking features

Mathematical consistency

You have to learn more than just FP

Referentially transparent

Symbols everywhere

Hand-writeable concise syntax

Obscure ugly notation

Very few language constructs

Documentation for most packages is short and lacking

Quick feedback

Too academic, hard to find "real world" code examples

Functions curry automatically

You need some time to start seeing results

Easy to read

Lazily evaluated

Popular in teaching

Only pure functional programming

Easy syntax for people with a STEM degree

Curried type signatures obfuscate what were the in and out types originally

Powerful categorical abstractions

My Recommendation for Elm

My Recommendation for Elm

Compile errors are human-friendly

Missing syntactic sugar ('where' clauses, pattern guards)

The Elm architecture offers a simple pattern for all programs

No Genericness in the future

Easier to make front ends than JS

Code Repetition

Avoids advanced FP topics such as Monads

Issues are swept under the rug

Growing community

Updates break existing code often

No run-time exceptions

Good for beginners, not good for experts

Good tooling

Community harsh if criticised

Inferred static typing

Features get removed without warning

Super easy refactoring with very helpful compiler errors

Limited js interop

Great and simple way to learn Purely Functional Programming

Lack of typeclasses

Missing syntactic sugar

Not quite Haskell semantics

Simpler syntax than Haskell

No higher-kinded types

Easy to code review

Good documentation

Static module system

Designed around high-level front-end development

Instant gratification with GUI's

Batteries included

Reactive programming is baked in

Higher confidence in code correctness and quality

Time-travelling debugger and Hot-swapping of code

Tailor-made for games

High-level Functional-Reactive Code

My Recommendation for F#

My Recommendation for F#

Concise syntax

Has no ad-hoc polymorphism (á la Type Classes)

Easier transition from other paradigms

Infested with OOP

.NET Interoperability

Multiplatform, it runs on .Net Core

You can run F# in the browser

Natively supported by Visual Studio

Allows writing predictable code

Fall into the pit of success

Type Providers

F# is supported by Xamarin

My Recommendation for Elixir