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Gleam

Gleam

Gleam is a functional programming language that runs upon BEAM(The Erlang virtual machine). The compiler is mainly written in Rust.

==

1. How to install

There is a precompiled binaries in the Github release page.

If you prefer package managers other than the precompiled binary, use brew.

brew update
brew install gleam

It’s available on Nix, too.

nix-shell -p gleam

You should install Erlang (Erlang OTA). If you don’t know where to start, visit https://www.erlang-solutions.com/downloads/.

2. Writing codes and running them

You should create a project to run code and scripts. At least, if you’re using Gleam 1.9.1.

Let me tell you that the shell commands are in PowerShell, not a normal bash or zsh.

You can create a new project by invoking gleam new command.

PS C:\Users\ch1keen\Downloads\gleam-v1.9.1-x86_64-pc-windows-msvc> .\gleam.exe new hello_world
Your Gleam project hello_world has been successfully created.
The project can be compiled and tested by running these commands:

        cd hello_world
        gleam test

Structure of a gleam project is easy enough.

PS C:\Users\ch1keen\Downloads\gleam-v1.9.1-x86_64-pc-windows-msvc\hello_world> tree /F
Folder PATH listing for volume Data
Volume serial number is DEAD-BEEF
C:.
│  .gitignore
│  gleam.toml
│  README.md
│
├─.github
│  └─workflows
│          test.yml
│
├─src
│      hello_world.gleam
│
└─test
        hello_world_test.gleam

And by default, there is a 'hello world' code in the src/hello_world.gleam.

import gleam/io

pub fn main() {
  io.println("Hello from hello_world!")
}

Let’s run the code.

PS C:\Users\ch1keen\Downloads\gleam-v1.9.1-x86_64-pc-windows-msvc\hello_world> ..\gleam.exe run
Downloading packages
 Downloaded 2 packages in 0.11s
  Compiling gleam_stdlib
  Compiling gleeunit
  Compiling hello_world
   Compiled in 2.69s
    Running hello_world.main
Hello from hello_world!

There should be a build directory at the root of the project, if you didn’t see any errors, and saw the 'Hello'. Because we didn’t build the release version of the project, there is a directory build/dev. Let’s go to the directory to see results of the compilations.

PS C:\Users\ch1keen\Downloads\gleam-v1.9.1-x86_64-pc-windows-msvc\hello_world> cd .\build\dev\erlang\hello_world\ebin\
PS C:\Users\ch1keen\Downloads\gleam-v1.9.1-x86_64-pc-windows-msvc\hello_world\build\dev\erlang\hello_world\ebin> ls

    Directory: C:\Users\_ruby\Downloads\gleam-v1.9.1-x86_64-pc-windows-msvc\hello_world\build\dev\erlang\hello_world\ebin

Mode         Length Name
----         ------ ----
-a---          1324 hello_world_test.beam
-a---           182 hello_world.app
-a---          1244 hello_world.beam
-a---          6708 hello_world@@main.beam

Oh, there are .beam files.

3. Reference

4. See Also

  • Lustre is a web frontend framework inspired by Elm.

  • wisp is a practical web backend framework for Gleam.

If you’re a fan of Gleam language, or thinking that the language looks good, here are some articles about Gleam.