Scala CLI REPL

The REPL of scala-cli in Emacs term mode.

Installation

You can access the REPL loading scala-cli-repl.el and running scala-cli-repl.

It is possible to load an Sbt project in the REPL (i.e., be able to evaluate symbols defined in your project from the REPL) by setting the custom variable (setq scala-cli-load-repl-in-sbt-context ).

Also, if you like literate programming in Org Mode, you can load also ob-scala-cli.el, which lets you run blocks like the following

#+begin_src scala :scala-version 3.0.0 :dep '("com.lihaoyi::os-lib:0.9.0")
println("This is:" + os.pwd)
#+end_src

into the scala-cli REPL.

Ob-scala-cli

It is sufficient to have (scala . t) in your org-babel-load-languages, because ob-scala-cli will run for scala org blocks. For more information on how to enable an org babel language check here and here.

If you use lsp-mode and lsp-metals, you can also setup IDE style completion from within a src block with ob-scala-cli-lsp-org:

Installing scala-cli

You can check the instructions for your platform on https://scala-cli.virtuslab.org/install/.

At the time of writing this, the easy way (on Linux) is:

curl -fL https://github.com/Virtuslab/scala-cli/releases/latest/download/scala-cli-x86_64-pc-linux.gz | gzip -d > scala-cli
chmod +x scala-cli
sudo mv scala-cli /usr/local/bin/scala-cli

Org Babel

Make sure to use this snippet in your configuration to make sure that scala blocks get picked up by ob-scala-cli:

(add-to-list 'org-babel-load-languages '(scala-cli . t))

Supported parameters

Currently supported header parameters are:

• :scala-version

  you can define the Scala version you want your code to be evaluated in.

• :dep

  you pass a list of dependencies in Mill format as a list, see example block above

• :jvm

  you can set the JVM version to use for evaluating your code

**Note**: the code is evaluated in a global scope by default, so you can use variables and functions across the blocks. If you don’t want definitions to leak, wrap them in curly braces.

If you enjoy Elisp, you can get an updated list of valid parameters evaluating ob-scala-cli-supported-params.

Also see usage examples.

Useful options

• ob-scala-cli-default-params

  you can define default parameters locally or globally and don’t specify them each block. Example:

  (setq ob-scala-cli-default-params '(:scala-version "2.13.11" :jvm 17))
      

  then just write a code:

  println(s"""
   |Scala version: ${scala.util.Properties.versionString}
   |JVM version: ${System.getProperty("java.version")}""".stripMargin)
      

  **Note**: if you use dependencies in multiple blocks specify also :deps for faster evaluation.

• scala-cli-ob-force-kill

  if you run blocks with different options (Scala version, JVM version, deps, etc.), you could face with an error:

  Buffer ”Scala-Cli” has a running process; kill it? (y or n)

  Set this flag if you want to forcely kill the process and the buffer.

Similar projects

This is a port of ammonite-term-repl, which is now an archived repository.

You can still use Ammonite through this mode with:

(setq scala-cli-repl-program-args '("--power" "--amm"))