Language Server Protocol

Overview

The JMLtk Language Server Protocol (LSP) implementation provides IDE support for Java and KeY language files. To use the LSP, you need to download the current release of JMLtk and configure your editor to use the jmltk-lsp script.

Installation

Download the latest release of JMLtk from the releases page
Extract the archive to your preferred location
The jmltk-lsp script will be available in the bin directory of the installation

Replace /path/to/jmltk with the actual path to your JMLtk installation.

Configuration

The following configuration were tested:

Emacs (eglot)

Add the following configuration to your Emacs init file to enable LSP support for Java:

(setq eglot-server-programs nil)
(add-to-list 'eglot-server-programs
             '(java-mode  "/path/to/jmltk/bin/jmltk-lsp" "--stdio"))

KeY files are unknown to Emacs, also as JML files.

For KeY files you can just derive a new mode from prog-mode:

(define-derived-mode key-mode prog-mode "KEY"
  "Major mode for editing KEY"
  :syntax-table java-mode-syntax-table
  (setq-local comment-start "//")
  (setq-local comment-end "")
  (setq-local indent-tabs-mode nil))

(add-to-list 'eglot-server-programs
             '(key-mode  "/path/to/jmltk/bin/jmltk-lsp" "--stdio"))

For JML files, just add jml to the auto-mode-alist:

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

Neovim (nvim-lspconfig)

Add the following configuration to your Neovim init.lua to enable LSP support:

local lspconfig = require('lspconfig')

-- Define a custom configuration for jmltk-lsp
local configs = require('lspconfig.configs')
if not configs.jmltk_lsp then
  configs.jmltk_lsp = {
    default_config = {
      cmd = { '/path/to/jmltk/bin/jmltk-lsp', '--stdio' },
      filetypes = { 'java', 'key' },
      root_dir = lspconfig.util.root_pattern('.git'),
      settings = {},
    }
  }
end

-- Attach to Java files
lspconfig.jmltk_lsp.setup {
  on_attach = function(client, bufnr)
    -- Your on_attach configuration here
  end,
  capabilities = require('cmp_nvim_lsp').default_capabilities(),
}

Visual Studio code

Requires a written plugin….