Nix Options – A set of useful Emacs modes and functions for users of Nix and Nix OS.

nixos-options	helm-nixos-options	ivy-nixos-options	company-nixos-options	nix-sandbox

Usage

helm-nixos-options

The function helm-nixos-options is the one that you want to bind. You are free to choose where and if you want it global you can have this.

(global-set-key (kbd "C-c C-S-n") 'helm-nixos-options)

It looks like this

The description of the option is shown in the minibuffer

If you want more information, there is a detailed buffer when you press return

There are also other actions like inserting the current match into the buffer

ivy-nixos-options

Use this if you don’t want the rather heavy helm dependency. The function ivy-nixos-options is the one that you want to bind. You are free to choose where and if you want it global you can have this.

(global-set-key (kbd "C-c C-S-n") 'ivy-nixos-options)

(setq ivy-nixos-options-default 1)
; defines what function is being called when pressing return. I like to have it set to 2
; All of the actions can always be called when pressing M-o
; 1 = show the docs buffer (default)
; 2 = insert the string
; 3 = only show the description of the command

It looks like this

If you want more information, there is a detailed buffer when you press return

There are also other actions like inserting the current match into the buffer. The builtin help menu from ivy (display with M-o) shows all possible options. e.g. M-o i will insert the option

company-nixos-options

Add company-nixos-options to allowed company-mode backends list

(add-to-list 'company-backends 'company-nixos-options)

For now it shows the documentation of the option in a popup-buffer.

nix-sandbox

Utility functions to work with nix sandboxes.

• nix-shell-command composes command that can be executed in the given sandbox
• nix-shell executes a command in the given sandbox
• nix-compile compiles a program in the given sandbox
• nix-find-sandbox searches from the given path upwards until it finds a shell.nix or default.nix file.
• nix-current-sandbox searches for a sandbox file starting from the current working directory.
• nix-executable-find a replacement for the built-in executable-find. The function searches in the given sandbox for executables.

Flycheck

With this configuration flycheck can find executables of checkers that would be only accessible via nix-shell:

(setq flycheck-command-wrapper-function
        (lambda (command) (apply 'nix-shell-command (nix-current-sandbox) command))
      flycheck-executable-find
        (lambda (cmd) (nix-executable-find (nix-current-sandbox) cmd)))

Haskell Mode

Add these lines to your configuration to allow haskell-mode to look for ghc in the current sandbox.

(setq haskell-process-wrapper-function
        (lambda (args) (apply 'nix-shell-command (nix-current-sandbox) args)))