Emacs

The official LUMOS major mode for Emacs provides syntax highlighting and LSP integration via lsp-mode.

Installation

Using MELPA

(use-package lumos-mode
  :ensure t
  :hook (lumos-mode . lsp-deferred))

Using straight.el

(use-package lumos-mode
  :straight (lumos-mode :type git :host github :repo "getlumos/lumos-mode")
  :hook (lumos-mode . lsp-deferred))

Manual Installation

# Clone the repository
git clone https://github.com/getlumos/lumos-mode ~/.emacs.d/lumos-mode

# Add to load-path
(add-to-list 'load-path "~/.emacs.d/lumos-mode")
(require 'lumos-mode)

Requirements

Emacs 26.1+ (required)
lsp-mode - For LSP features
lumos-lsp - LSP server
Terminal window
```
cargo install lumos-lsp
```

Features

Syntax Highlighting

Keywords: struct, enum, type, mod, use, pub
Types: Primitives, Solana types, user-defined
Attributes: #[solana], #[account], #[deprecated]
Comments: Line (//) and block (/* */)

Smart Indentation

Automatic indentation with configurable offset (default: 4 spaces).

LSP Integration

Via lsp-mode:

Real-time diagnostics
Auto-completion
Hover documentation
Go to definition
Find references

Configuration

Basic Setup

(use-package lumos-mode
  :ensure t
  :mode "\\.lumos\\'"
  :hook (lumos-mode . lsp-deferred)
  :custom
  (lumos-indent-offset 4))

Custom LSP Server Path

(use-package lsp-mode
  :config
  (add-to-list 'lsp-language-id-configuration '(lumos-mode . "lumos"))

  (lsp-register-client
   (make-lsp-client
    :new-connection (lsp-stdio-connection "lumos-lsp")
    :activation-fn (lsp-activate-on "lumos")
    :server-id 'lumos-lsp)))

Keybindings

Default keybindings (with lsp-mode):

Key	Action
`M-.`	Go to definition
`M-,`	Go back
`M-?`	Find references
`C-c C-r`	Rename symbol
`C-c C-a`	Code action

Customization

Variables

;; Indentation offset
(setq lumos-indent-offset 2)

;; LSP server command
(setq lumos-lsp-server-command "lumos-lsp")

Troubleshooting

LSP not connecting

Verify lumos-lsp is installed:
Terminal window
```
lumos-lsp --version
```
Check LSP logs:
```
M-x lsp-workspace-show-log
```

Mode not activating

Ensure file association:

(add-to-list 'auto-mode-alist '("\\.lumos\\'" . lumos-mode))