What are the best functional languages with clean syntax?

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What are the best functional languages with clean syntax?

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Apr 6, 2023

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6 Options Considered

Best functional languages with clean syntax?	Price	Site	Paradigm
-- Haskell	-	https://www.haskell.org/	functional
-- Scheme	-	-	-
-- Elm	-	-	-
-- Elixir	-	https://elixir-lang.org	-
-- Erlang	-	-	-

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score 9 · Answer 1

Haskell

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

Difficult learning curve

Haskell lends itself well to powerful abstractions - the result is that even basic, commonly used libraries, while easy to use, are implemented using a vocabulary that requires a lot of background 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 rears its ugly head in the form of complicated error messages from type inference. See More

Specs

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

Paradigm:functional

Type System:static

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

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

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

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

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

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

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

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

Powerful categorical abstractions

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

Top Con

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

Top Pro

Open source

All Haskell implementations are completely free and open source. 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

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

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

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

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

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. This avoids you falling back on old habits and learn an entirely new way to program. 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 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

See All

score 7 · Answer 2

Scheme

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. Users 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

Very different semantics from mainstream programming languages

LISP-like languages are very different from mainstream languages (such as C/C++/Java/JavaScript/Python/you-name-it) - both in semantics and syntax. This, in turn, severely limits uses of whatever-learned-with-Scheme, for real-world use. See More

NiceAshaVahishta's Experience

Have spent over 10 years programming with lisp based languages 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

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

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. See More

Top Con

Little 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

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

Multi platform

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

See All

score 3 · Answer 3

Elm

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 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

Specs

Current stable version:0.19.1

GZipped size:23.2 kB

Platforms:Windows Linux Mac Web

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

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

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

Poor tooling

There are editor plugins, but neither of them support basic features yet like navigate to referenced definition show expression type 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 Con

Not database-friendly

It is lots of work to make a server or database your "one source of truth", as Elm makes you write endless JSON parse boilerplate to talk to the server. 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

Poor Windows support

Few if any of Elm's core contributors are Windows users and breaking bugs are sometimes left for weeks or months. 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 than compiler-error driven. See More

Top Con

Adds an additional layer of abstraction

Some users claim that Elm adds an additional layer of abstraction, meaning that it is one more hurdle between the brain and the product. See More

Top Pro

Interactive Programming and Hot Swapping

Support for hot swapping and interactive programming is included. 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 Pro

Low mental overhead

Few programming concepts need to be kept in mind while programming in Elm (particularly the case from version 0.17 onwards). This is beneficial for learners new to programming, but it also helps more experienced programmers to focus on application logic instead of "administration" needed to work in a particular framework/language. This keeps the cost of refactoring low, which is also a pro for beginners and experts alike, making it sensible to stay in Elm after gaining more experience. 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. No semicolons, weird operators, unpronounceable functions. Elm strives to have unsurprising naming and simplified syntax relative to other Haskell/ML-like languages. See More

Top Pro

Not quite Haskell semantics

Luckily you do not have to learn Haskell to be able to do any Elm. It is meant to be a language that compiles to Javascript, so for Javascript programmers (Front end) not for CS students who want to learn as many different algorithms as possible. See More

Top Pro

Growing community

Top Pro

Haskell-like modules

Elm uses easy to use Haskell-like 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

High-level Functional-Reactive Code

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

See All

score 2 · Answer 4

Elixir

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 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

Specs

Current stable version:1.11.2

GZipped size:3.61 MB (without required Erlang VM)

Site:https://elixir-lang.org

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 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

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

Powerful metaprogramming

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

Great for concurrency

Leverages the existing Erlang BEAM VM See More

See All

score 4 · Answer 5

Erlang

Top Pro

Slightly unusual syntax actually helps when learning functional programming as a new concept

As the syntax does not resemble other languages, you do not get confused by similar looking different concepts. See More

Top Con

Bad performance

DecorousTaweret's Experience

I built a big commercial product with Erlang See More

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

Dynamically typed

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 Con

Eccentric 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

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 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

Low Latency

Fast and deterministic process scheduling with soft real-time guarantees 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 Pro

Light processes

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

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

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

See All

score 2 · Answer 6

Kotlin

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

Specs

Current stable version:1.3

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

See All

What are the best functional languages with clean syntax?

6 Options Considered

Haskell

My Recommendation for Haskell

My Recommendation for Haskell

Highly transferable concepts

Difficult learning curve

Referentially transparent

You need some time to start seeing results

Easy to read

You have to learn more than just FP

Very few language constructs

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

Functions curry automatically

Language Extensions lead to unfamiliar code

Quick feedback

Symbols everywhere

Powerful categorical abstractions

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

Open source

Documentation for most packages is short and lacking

Easy syntax for people with a STEM degree

Lazily Evaluated

Hand-writeable concise syntax

Package manager is unstable & lacking features

Forces you to learn pure functional programming

Mathematical consistency

Popular in teaching

Scheme

My Recommendation for Scheme

My Recommendation for Scheme

Simple syntax

Very different semantics from mainstream programming languages

Great at teaching fundamental programming ideas

Fragmented ecosystem

Multiparadigm

Little Job Market

Robust metaprogramming

Multi platform

Great, well known textbooks

No Magic - it's clear how everything works

Elm

My Recommendation for Elm

My Recommendation for Elm

Designed around high-level front-end development

Lack of typeclasses

No run-time exceptions

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

Inferred static typing

Poor tooling

Good documentation

Not database-friendly

Great and simple way to learn Purely Functional Programming

Poor Windows support

Super easy refactoring with very helpful compiler errors

Adds an additional layer of abstraction

Interactive Programming and Hot Swapping

Good tooling

Low mental overhead

Missing Syntactic sugar

Not quite Haskell semantics

Growing community

Haskell-like modules

High-level Functional-Reactive Code

Elixir

My Recommendation for Elixir

My Recommendation for Elixir

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

Some design choices may seem strange

Great documentation

Great getting started tutorials

Easy to download libraries

Powerful metaprogramming

Full access to Erlang functions

Great for concurrency

Erlang

My Recommendation for Erlang

My Recommendation for Erlang

Slightly unusual syntax actually helps when learning functional programming as a new concept

Bad performance