clojureexecutableleiningennixoscider

How to load this Clojure project in my cider REPL? Why I am receiving the message "The clojure executable isn’t on your ‘exec-path’" (NixOS)?

Recently, I started learning Clojure. I have been using Emacs, and cider (REPL). Also, I have NixOS as OS.

I have been able to successfully program in Clojure using this environment. Usually, I create the files, then I go to the directory where the .clj are, I execute cider-jack-in, a REPL is created, and interactive programming magic happens. Thus, I am able to load the file, load new versions of old functions, etc.

It also works if I just start Emacs and execute `cider-jack-in. The mini-buffer asks:

Are you sure you want to run `cider-jack-in' without a Clojure project? (y or n)

After answering y, everything works fine.

While reading the book Clojure for the Brave and True, I have also successfully used:

$ lein run

For learning purposes, I decided to explore some open source projects. Thus, I did a git clone of this open-source project.

Being on the folder, I decided to reproduce the steps that have worked so far. However, it does not work. After executing cider-jack-in, the mini-buffer echoes the following:

The clojure executable isn’t on your ‘exec-path

Also, if I try with lein I get:

[pedro@system:~/projects/http-cron]$ lein run
No :main namespace specified in project.clj.

Obs.: If I type clojure on the shell, this is what I get:

[pedro@system:~]$ clojure
The program 'clojure' is not in your PATH. You can make it available in an
ephemeral shell by typing:
  nix-shell -p clojure

Why is this happening?

How can I solve this (considering that I am using NixOS)?

Solution

  • Going the imperative route, depending on whether you use NixOS with channels (default) or flakes, you can permanently install clojure into your environment with:

    The preferred (declarative) way would however be adding clojure to environment.systemPackages in /etc/nixos/configuration.nix and running sudo nixos-rebuild switch.