case.hx

A Helix⁠ plugin for changing keyword case, written for the Steel⁠ plugin system.

Install

With forge

forge⁠ is the Steel package manager:

forge pkg install --git https://github.com/apothecary103/case.hx

With Nix

The plugin is packaged in helix-plugins-nix⁠ as case. Plugins need the steel-event-system branch of Helix, which is already packaged in Nix so you can just use pkgs.steelix instead of pkgs.helix.

Add the flake to your inputs:

inputs.helix-plugins.url = "github:maxschipper/helix-plugins-nix";

Then, with Hjem⁠:

{ pkgs, inputs, ... }:
{
  nixpkgs.overlays = [ inputs.helix-plugins.overlays.default ];
  hjem.extraModules = [ inputs.helix-plugins.hjemModules.default ];

  hjem.users.<username>.programs.helix = {
    enable = true;
    plugins = with pkgs.helixPlugins; [ case ];
  };
}

The same plugins option exists on the home-manager module (inputs.helix-plugins.homeManagerModules.default). Without either module, build and copy the cog by hand:

nix build "github:maxschipper/helix-plugins-nix#helixPlugins.case"
cp -rL result ~/.local/share/steel/cogs/case.hx

Configure

However you installed it, require it from ~/.config/helix/init.scm and bind the commands:

(require "case.hx/case.scm")
(require (only-in "helix/keymaps.scm" add-global-keybinding))

;; ` enters case mode. l, u and a are helix builtins, the rest come from case.scm.
(define case-mode
  (hash "l" "switch_to_lowercase"
        "u" "switch_to_uppercase"
        "a" "switch_case"
        "c" ":switch-to-camel-case"
        "p" ":switch-to-pascal-case"
        "s" ":switch-to-snake-case"
        "k" ":switch-to-kebab-case"
        "C" ":switch-to-constant-case"
        "t" ":switch-to-title-case"
        "S" ":switch-to-sentence-case"))

(add-global-keybinding (hash "normal" (hash "`" case-mode)
                             "select" (hash "`" case-mode)))

Every command also works from the command line, for example :switch-to-snake-case.

Commands

Key	Command	hello_world becomes
`c	switch-to-camel-case	helloWorld
`p	switch-to-pascal-case	HelloWorld
`s	switch-to-snake-case	hello_world
`k	switch-to-kebab-case	hello-world
`C	switch-to-constant-case	HELLO_WORLD
`t	switch-to-title-case	Hello World
`S	switch-to-sentence-case	Hello world
`l	switch_to_lowercase (builtin)	hello_world
`u	switch_to_uppercase (builtin)	HELLO_WORLD
`a	switch_case (builtin)	HELLO_WORLD

Behaviour

Words are split on whitespace, _ and -, and at camel boundaries, so fooBar and HTTPServer split into foo Bar and HTTP Server. Everything else, including ., , and digits, stays inside a word, so prose and paths come through unharmed.

Conversion runs a line at a time and leaves each line's indentation and trailing padding alone, so a multi-line selection keeps its shape.

All selections are converted at once, cursors end up on the rewritten text, and the whole thing is a single undo step.

Development

This flake is for developing the plugin, not installing it. For installation, see helix-plugins-nix⁠.

Run nix develop to get a shell with steel on PATH, and nix flake check to run the tests. Without Nix, you can run the same tests with steel test.scm.

Acknowledgements

Inspired by helix#12043⁠ and coerce.nvim⁠.