Editor setup

Syntax highlighting, completion, and inline validation for Fusefiles

A Fusefile is YAML, but it is named Fusefile with no extension. Editors detect file types by extension, so out of the box you get a plain, unhighlighted buffer, and the JSON Schema never loads even though fuse init writes the modeline for it.

One line of config per editor fixes both at once: tell it that Fusefile is YAML, and everything else follows.

What to associate

Three patterns cover every Fusefile you are likely to open:

The CLI only resolves ./Fusefile by default; the other two are naming conventions, and you point fuse up -f at them explicitly.

VS Code

Install the YAML extension, then add this to your user settings.json (or the workspace’s .vscode/settings.json, to set it for everyone on the repo):

{
  "files.associations": {
    "Fusefile": "yaml",
    "Fusefile.*": "yaml",
    "*.fuse": "yaml"
  },
  "yaml.schemas": {
    "https://raw.githubusercontent.com/folsomintel/fuse/main/schema/fusefile-v1.json": [
      "Fusefile",
      "Fusefile.*",
      "*.fuse"
    ]
  }
}

files.associations gets you highlighting. yaml.schemas gets you completion, hover docs, and red squiggles on invalid fields, and it works even for Fusefiles that predate the modeline fuse init now writes.

Zed

Zed ships yaml-language-server, so both halves are one settings block. Add it to ~/.config/zed/settings.json, or to .zed/settings.json in the repo:

{
  "file_types": {
    "YAML": ["Fusefile", "Fusefile.*", "*.fuse"]
  },
  "lsp": {
    "yaml-language-server": {
      "settings": {
        "yaml": {
          "schemas": {
            "https://raw.githubusercontent.com/folsomintel/fuse/main/schema/fusefile-v1.json": [
              "Fusefile",
              "Fusefile.*",
              "*.fuse"
            ]
          }
        }
      }
    }
  }
}

Neovim

Filetype detection goes in your config as a vim.filetype.add call:

vim.filetype.add({
  filename = { ["Fusefile"] = "yaml" },
  pattern = { ["Fusefile%..*"] = "yaml" },
  extension = { fuse = "yaml" },
})

That alone gives you highlighting, and the modeline in a scaffolded Fusefile is enough for yamlls to pick up the schema. To bind the schema by filename instead, so it applies to Fusefiles without a modeline:

require("lspconfig").yamlls.setup({
  settings = {
    yaml = {
      schemas = {
        ["https://raw.githubusercontent.com/folsomintel/fuse/main/schema/fusefile-v1.json"] = {
          "Fusefile",
          "Fusefile.*",
          "*.fuse",
        },
      },
    },
  },
})

Vim

autocmd BufNewFile,BufRead Fusefile,Fusefile.*,*.fuse setfiletype yaml

Helix

In ~/.config/helix/languages.toml. Note that file-types replaces the built-in list rather than extending it, so keep yaml and yml:

[[language]]
name = "yaml"
file-types = ["yaml", "yml", "fuse", { glob = "Fusefile" }, { glob = "Fusefile.*" }]

Helix uses yaml-language-server for YAML, so the modeline supplies the schema once the file is detected.

JetBrains IDEs

Settings → Editor → File Types → YAML, and add Fusefile, Fusefile.*, and *.fuse to the registered patterns. The bundled YAML support reads the modeline for schema validation.

Emacs

(add-to-list 'auto-mode-alist '("/Fusefile\\(\\..*\\)?\\'" . yaml-mode))
(add-to-list 'auto-mode-alist '("\\.fuse\\'" . yaml-mode))

Terminal

For bat, add these to ~/.config/bat/config:

--map-syntax "Fusefile:YAML"
--map-syntax "Fusefile.*:YAML"
--map-syntax "*.fuse:YAML"

For GitHub’s web view and diffs, a .gitattributes in the repo holding your Fusefiles does the same job:

Fusefile    linguist-language=YAML
Fusefile.*  linguist-language=YAML
*.fuse      linguist-language=YAML

Checking it worked

Open a Fusefile and confirm three things:

1. Keys and strings are colored, and the file’s language shows as YAML.
2. Typing res on a blank line offers resources.
3. Changing version: 1 to version: 2 is flagged inline.

If highlighting works but completion does not, the language server is not running or the schema is not bound; if neither works, the file association did not take.