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hamler-lang/hamler

Haskell-style functional programming language running on Erlang VM.
Source code at GitHub https://www.hamler-lang.org/
hamler-lang/hamler.json
{
  "createdAt": "2019-04-18T13:41:46Z",
  "defaultBranch": "master",
  "description": "Haskell-style functional programming language running on Erlang VM.",
  "fullName": "hamler-lang/hamler",
  "homepage": "https://www.hamler-lang.org/",
  "language": "Erlang",
  "name": "hamler",
  "pushedAt": "2022-02-03T11:22:57Z",
  "stargazersCount": 1035,
  "topics": [
    "compiler",
    "hamler",
    "programming-language"
  ],
  "updatedAt": "2025-10-17T23:07:37Z",
  "url": "https://github.com/hamler-lang/hamler"
}

The Hamler Programming Language

Section titled “The Hamler Programming Language”

GitHub Release Docker Pulls Slack Twitter Community

Hamler - Haskell-style functional programming language running on Erlang VM.

Hamler is a strongly-typed language with compile-time type-checking and built-in support for concurrency and distribution.

Hamler empowers industries to build the next generation of scalable, reliable, real-time applications, especially for 5G, IoT, and edge computing.

Why Hamler?

Section titled “Why Hamler?”

For almost a decade, we have been developing software systems based on Erlang/OTP, especially our main product EMQ X - the scalable open-source MQTT broker. So, we have always believed that Erlang is a masterpiece of engineering. With amazing concurrency, distribution, and fault tolerance, it is one of the few general-purpose language platforms able to properly handle concurrency and soft realtime.

However, from all the experience writing Erlang, we believe that the following features can help Erlang programmers better adapt to the coming wave of 5G, IoT, and edge-programming and attract more people to using BEAM.

  • Compile-time type checking and type reference
  • ADTs, Function Composition, Type Classes
  • More friendly syntax for prosperous communities
  • Functor, Applicative, and Monad…:)

Now all the features are available in the Hamler programming language.

Features

Section titled “Features”
  • Functional programming
  • Haskell and ML style
  • Compile-time type Checking/Inference
  • Algebraic data type (ADT)
  • Functions, higher-order functions
  • Currying and partial application
  • Pattern matching, and Guards
  • List comprehension
  • Applicative and Monad
  • Advanced module system
  • Built-in concurrency

Design

Section titled “Design”

The Hamler compiler architecture is shown as below:

hamler-compiler

The Hamler 0.1 compiler was forked from [PureScript][PureScriptHamler] 0.13.6. The Hamler source code is parsed to generate CST, then CoreErlang’s IR is generated after CST -> AST -> CoreFn’s syntax tree transformation, syntax analysis and type checking. The code is then used by the Erlang compiler to generate the final Beam bytecode.

[PureScriptHamler] !: https://github.com/hamler-lang/purescript

Installation

Section titled “Installation”

Get the installation package through Github Release

packages for windows will be coming soon…

Linux

Terminal window
$ tar zxvf hamler-$version.tgz -C /usr/lib/
$ ln -s /usr/lib/hamler/bin/hamler /usr/bin/hamler

Centos 7

Terminal window
$ rpm -ivh hamler-$version-1.el7.x86_64.rpm

Debian 8 / Debian 9 / Debian 10 / Ubuntu 16.04 / Ubuntu 18.04 / Ubuntu 20.04

Terminal window
$ dpkg -i hamler_$version_amd64.deb

Homebrew(macOS)

Terminal window
$ brew tap hamler-lang/hamler
$ brew install hamler

Project Layout

Section titled “Project Layout”
Terminal window
├── .github/workflows     # ci
├── app                   # hamler commands, such as `compile`, `repl`, ...
├── deploy
├── doc                   # link to hamler documents
├── lib                   # hamler standard libraries
∣   ├── Control           # common control structures, concurrent Process, and OTP behaviours.
∣   ├── Data              # commonly used data structures and functions
∣   ├── Database          # common databases in erlang, such as ETS, DETS, and Mnesia
∣   ├── Foreign
∣   ├── Network           # hamler network libraries.
∣   ├── System            # system libraries including IO, VM, OS, Env, File, Random, Timer, and Logger.
∣   ├── Test              # hamler QuickCheck test framework
∣   ├── Foreign.hm        # hamler FFI functions
∣   └── Prelude.hm        # functions exported by default
├── repl
∣   └── replsrv           # hamler REPL server
├── src/Language          # hamler compiler source
∣   ├── Hamler
∣   ∣   ├── CodeGen.hs    # convert CoreFn to CoreErlang
∣   ∣   ├── Make
∣   ∣   ├── Make.hs
∣   ∣   └── Util.hs
∣   └── Hamler.hs
├── tests
∣   ├── Test              # test cases for hamler libraries
∣   ∣   ├── Control
∣   ∣   ├── Data
∣   ∣   ├── Database
∣   ∣   ├── Network
∣   ∣   └── System
∣   ├── Test.hm           # entrance to execute test cases
∣   └── Main.hs
├── .gitignore
├── LICENSE
├── Makefile
├── README.md
├── Setup.hs
├── hamler.cabal
├── package.yaml
└── stack.yaml

Build from source code

Section titled “Build from source code”

Required

Building

  1. Clone hamler from the git repo

    Terminal window
    $ git clone https://github.com/hamler-lang/hamler.git
    $ cd hamler

  2. Configuring

    Terminal window
    $ export LC_ALL=en_US.UTF-8

  3. Building

    Terminal window
    $ make

  4. Testing

    Terminal window
    $ make test

  5. Install hamler

    Terminal window
    $ sudo make install

Create a project

Section titled “Create a project”
Terminal window
$ mkdir demo-project
$ cd demo-project
$ hamler init
$ make
$ make run

Try the interpreter

Section titled “Try the interpreter”
Terminal window
$ hamler repl


> -- List, range and enums
> [1,2,3]
> [1..10]
> ['a'..'z']


> -- erlang style maps
> import Data.Map as Map
> -- New map
> m = #{"foo" => "bar", "bar" => "foo"}
> -- Match Map
> #{"foo" := a, "bar" := b} = m
> -- get, put
> Map.get "foo" m -- a = "bar"
> Map.get "bar" m -- b = "foo"
> m1 = Map.put "key" "val" m
> -- keys, values
> keys = Map.keys m
> values = Map.values m

Documentation

Section titled “Documentation”

Community, discussion, and supports

Section titled “Community, discussion, and supports”

You can reach the Hamler community and core team via the following channels:

Contributing

Section titled “Contributing”

To contribute to Hamler project:

  • Report issues : submit any bugs, issues to [hamler/issues][hamler-issues]
  • Contribute code: Reference roadmap as a guidance for new features. Fork the project, and submit feature requests to [hamler-lang/hamler][hamler-project]
  • Submit a proposal: Fork the [hamler-wiki][hamler-wiki] project and submit a pull request

[hamler-issues] !: https://github.com/hamler-lang/hamler/issues [hamler-project] !: https://github.com/hamler-lang/hamler [hamler-wiki] !: https://github.com/hamler-lang/hamler-wiki

Core Team

Section titled “Core Team”

The Hamler core team comes from EMQ Technologies Co., Ltd. now:

  • Feng Lee: Designer of Hamler Language
  • Yang M: Implemented Hamler Compiler
  • S Hu: Maintainer of the documentations
  • Shawn: Contributed [rebar3_hamler][rebar3_hamler] plugin
  • Rory Z: Contributed [homebrew][homebrew] install package
  • wivwiv: Designer of hamler-lang.org website
  • CrazyWisdom: Maintainer of hamler-lang.org
  • ysfscream: Maintainer of hamler-lang.org
  • juan6666：Designer of Hamler language logo

[homebrew] !: https://github.com/hamler-lang/homebrew-hamler [rebar3_hamler] !: https://github.com/hamler-lang/rebar3_hamler

License & Credits

Section titled “License & Credits”

We would like to express our great appreciation to the [PureScript][PureScriptSite] team and community for all years of efforts making its amazing compiler, especially CoreFn and its incredible adaptability.

The hamler language project is licensed under BSD3, see [LICENSE]!(./LICENSE).

[PureScriptSite] !: https://www.purescript.org/

About EMQ

Section titled “About EMQ”

EMQ is an open-source software company providing highly-scalable, real-time messaging and streaming platforms for IoT applications in the 5G Era.