Install OSL

Install the compiler, check it works, and set up your editor. About two minutes.

OSL compiles your code to Go, and Go turns it into a native executable. So you need two things on the machine where you build: OSL and a recent Go toolchain (1.25 or newer). The programs you build need neither: they are single files that run on their own.

1. 1

   Install Go

   Download it from go.dev/dl, or use your package manager:

   Terminal

   brew install go          # macOS
   sudo pacman -S go        # Arch
   sudo apt install golang  # Debian and Ubuntu

   Check it with go version.

2. 2

   Install OSL

   One line installs both osl, the compiler, and opal, the project and package manager:

   $curl -fsSL https://gosl.mistium.com | sh
3. 3

   Check it

   Terminal

   osl version
   opal version

   Both print a version number. If your shell can't find them, open a new terminal so it picks up the updated PATH.

4. 4

   Run something

   Make a file called hello.osl:

   main.osl

   log "Hello from OSL"

   RunGoClick the code to edit it

   Then run it:

   Terminal

   osl run hello.osl

   The first build takes a few seconds while Go compiles OSL's runtime. After that, builds come from a cache and take a fraction of a second.

Set up your editor#

osl lsp is a language server: diagnostics as you type, completion, hover types, go to definition, rename, formatting and quick fixes. Any editor that speaks the Language Server Protocol can use it. Point the editor's LSP client at the command osl lsp for files ending in .osl.

For Neovim, for example:

vim.lsp.config("osl", {
  cmd = { "osl", "lsp" },
  filetypes = { "osl" },
  root_markers = { "opal.json", ".git" },
})
vim.lsp.enable("osl")
vim.filetype.add({ extension = { osl = "osl" } })

You can also check a whole project from the terminal, which is what the editor sees:

osl lsp check main.osl

Build from source#

The compiler is open source. To build the newest version yourself:

git clone https://git.rotur.dev/osl/.go osl
cd osl
go build -o osl .
./osl setup        # installs it as the osl and opal commands

Keep it up to date#

osl update

osl uninstall removes it again.

Next#