eglot-luau is an Emacs package that adds support for the Luau Lanuage Server to eglot.

eglot-luau provides the following customizable variables:

• eglot-luau-rojo-sourcemap-enabled: boolean

  This variable determines whether eglot-luau will start a Rojo process to generate sourecemaps for the language server. The value of this variable is nil by default.

• eglot-luau-rojo-sourcemap-includes-non-scripts: boolean

  This variable determines whether non-script instances are present in the Rojo sourcemap. The value of this variable is nil by default.

• eglot-luau-auto-update-roblox-types: boolean

  This variable determines whether eglot-luau-setup will attempt to download the latest Roblox type definitions. The value of this variable is nil by default.

• eglot-luau-auto-update-roblox-docs: boolean

  This variable determines whether eglot-luau-setup will attempt to download the latest Roblox docs. The value of this variable is nil by default.

• eglot-luau-roblox-security-level: string

  This variable determines the security level of type definitions downloaded when eglot-luau-lsp-auto-update-roblox-types is non-nil. The available options are None, LocalUserSecurity, PluginSecurity, and RobloxScriptSecurity. The value of this variable is PluginSecurity by default.

• eglot-luau-rojo-project-path: string

  This variable determines the path passed to Rojo for sourcemap generation. The value of this variable is default.project.json by default.

• eglot-luau-fflags-enabled: boolean

  This variable determines whether the language server will have any FFlags enabled. The value of this variable is t by default.

• eglot-luau-fflag-overrides: alist

  This variable allows overriding FFlags. It is an alist mapping the names of FFlags to their desired values. An example value is ``(("LuauNonStrictByDefaultBetaFeature" "False"))`. The value of this variable is the empty list by default.

• eglot-luau-sync-fflags: boolean

  This variable determines whether eglot-luau-setup will attempt to download the latest Roblox FFlag configuration. The value of this variable is t by default.

• eglot-luau-custom-type-files: list

  This variable is a list of paths to custom type definition files to supply to the language server. The value of this variable is the empty list by default.

• eglot-luau-custom-doc-files: list

  This variable is a list of paths to custom doc files to supply to the language server. The value of this variable is the empty list by default.

• eglot-luau-server-executable: string

  This variable determines how to locate the language server. The value of this variable is luau-lsp by default (i.e. it assumes luau-lsp is on the PATH environment variable).

eglot-luau is also configurable using LSP's "workspace configuration," as described in the Eglot documentation.

The entry point to the package is the function eglot-luau-setup. This function should be called after eglot is loaded.

Below is a example configuration using use-package:

(use-package eglot-luau
  :demand t
  :after (lua-mode eglot)
  :functions eglot-luau-setup
  :config (eglot-luau-setup)
  :custom
  (eglot-luau-rojo-sourcemap-enabled t)
  (eglot-luau-rojo-sourcemap-includes-non-scripts t)
  (eglot-luau-auto-update-roblox-docs t)
  (eglot-luau-auto-update-roblox-types t)
  (eglot-luau-fflag-overrides '(("LuauNonStrictByDefaultBetaFeature" "False")))
  :hook (lua-mode . eglot-ensure))

end completion does not work. This seems to be caused by a deeper issue in eglot that causes \n to be unusable as a trigger character. Since luau-lsp is hardcoded to use \n as a trigger character for end completion, this is not very straightforward to fix.

Additionally, eglot-luau does not support bytecode generation, not does it support luau-lsp's Roblox Studio companion plugin.