Haskell Vs. OCaml: The Difference


Haskell and OCaml are widely used programming languages. But what are the differences? Do they follow Object Oriented Concepts? Do these programming languages have similarities

? Who uses these two languages? So many questions must be popping into your head. So, let us get down to understanding the differences between these two languages.

Time to dive right into it!


Haskell Vs. OCaml: Know the Differences

Haskell is considered an alternative for OCaml, and vice versa. But what differences do they hold? Let’s discuss the following:


Haskell is considered a pure and lazy language, and ad hoc polymorphism is present in it. 

OCaml is an impure and strict language, and ad hoc polymorphism is absent, unlike in Haskell, where type classes are used.

Purely functional programming, standard, contemporary, and non-strict are all characteristics of this language. It has been specifically created to handle various numerical and symbolic applications. It has a highly rich internal architecture and an expressive syntax.

It is a powerful programming language that supports object-oriented, imperative, and functional programming. It is a preferred choice in businesses. 

This language works on VS code. However, its primary platform to run the code would be the Glasgow Haskell Compiler (GHC). 

This language works well with VS code too. It is believed to be the officially recommended editor. You can also opt for Vim and Emacs.

Haskell is renowned for its lengthy and confusing compile errors.

Even if some edge cases in OCaml can result in errors that are similarly nasty, they are far less common than they are in Haskell since the type-system characteristics that create them aren’t as widely utilized there.

Its roots come from metathetical function and lambda calculus.

Array, tuple, data stream, and other common data types are supported and provided by Ocaml, which also contains a large number of data types.

Similar to Java, C, and C++, Haskell is a strongly typed language, making it relatively simple to check for errors only at compilation time.

It is often an extension of the Categorical Abstract Machine Language or Caml. In this case, the O in OCaml stands for an objective.


Features of Haskell and OCaml

Now, we shall see the features of the two programming languages:

  • The evaluation of parameters in functions is omitted in functional programming languages like Haskell. This improves the code’s performance while greatly assisting program composition. This is called lazy evaluation. 
  • Virtual processors are called threads that handle and process stages in a program. When a language only has one thread, only one execution is taking place at once. Given that Haskell is a multi-threaded language, it can execute program statements in parallel. The execution of a programming language has more processing power when multi-threading is used.
  • When variable types are known at build time, a language is said to be statically typed. It aids programmers in locating compile-time problems. Large-scale programs’ complexity is lowered as a result.
  • The programmer must release the memory after utilizing it in a language like C by using the keywords malloc or calloc. However, this burden is removed from the programmer with functional programming languages like Haskell.
  • The evaluation of parameters in functions is omitted in functional programming languages like Haskell. This improves the code’s performance while greatly assisting program composition.
  • A wide range of systems can run OCaml. Platforms that are backed by the community, as well as those that are officially endorsed, exist.
  • It allows for the development of sophisticated client-side applications.
  •  Direct OCaml to Java bytecode compilation is also possible using OCaml-Java.
  • A bytecode compiler and a native code compiler are two batch compilers that OCaml provides. Bytecode compilers produce compact, portable executables fast. The native code compiler takes longer, but it generates machine code that is more effective and performs to the highest standards currently set by compilers.
  • Similar to generics in Java, C#, and C++, parametric polymorphism enables the creation of abstractions that function across many data types.
  • Because of type inference, you don’t have to annotate every variable in your program with its type. Instead, types are deduced from the way a value is applied.
  • Excellent support for programming without modifying data structures called immutable programming.
  • Debugging OCaml applications may be done using a variety of techniques. The interactive REPL provides a simple, quick, and easy way to test functions. The interactive system offers a low-cost method of “tracing” calculations for more complicated scenarios. Finally, OCaml offers ocamldebug, a symbolic (i.e., source level) replay debugger, which is a very potent tool for monitoring a program’s execution. 

Companies That Use These Languages


  • Facebook
  • The New York Times
  • Bank of America
  • Microsoft
  • IBM
  • Twitter


  • Maersk Digital
  • HERP, Inc.
  • rung
  • Jane Street
  • Diffbot
  • Agora
  • CrowdStrike
  • Facebook

Similarities Between Haskell And OCaml

  • Polymorphism is supported in Haskell. For instance, the code above supports lists of characters, lists of lists, floating-point numbers, integers, and more. In OCaml, parametric polymorphism is used for the creation of abstractions that function across many data types.
  • In OCaml, we use garbage collection (GC), a characteristic of nearly all contemporary high-level languages, as automated memory management. In Haskell, storage is allocated, initialized implicitly, and recovered automatically by the garbage collector.

Final Thoughts

So, you can see how Haskell differs from OCaml, and at a certain point, they show similarities. Find the right one for yourself and start coding!


1. Does OCaml use ==?

Yes, the programming language OCaml uses the ==. In OCaml, the equality operators = and == are paired with the inequality operators != and !>.

2. Why does Jane Street use OCaml?

Jane Street uses OCaml because they discovered that OCaml combined the greatest features of dynamic and compiled languages. It is succinct, safe, and performant because of an expressive type system with strong inference.

3. What is Haskell used for?

The primary technology that enables us to produce high-caliber software is Haskell. The most crucial factors in determining software quality are accuracy, performance, and maintainability.

4. Is Haskell harder than C++?

Yes, Haskell is actually harder than C++ when learning the language. It is believed to be one of the toughest languages to learn. However, this should not deter you from learning the language.

While you’re exploring the differences between Haskell and OCaml, you might also be interested in how popular games like Fortnite support the LGBTQIA community.



Jonas Muthoni is the Founder and CEO of Deviate Agency; he has contributed to several online publications, including Forbes. He loves to write on topics ranging from leadership and business to technology. Writing has always been his passion, and He has been writing for online publications over the last several years.