1 files changed, 44 insertions, 0 deletions
diff --git a/lua/lspconfig/server_configurations/lean3ls.lua b/lua/lspconfig/server_configurations/lean3ls.lua
new file mode 100644
index 00000000..347d53b6
--- /dev/null
+++ b/lua/lspconfig/server_configurations/lean3ls.lua
@@ -0,0 +1,44 @@
+local util = require 'lspconfig/util'
+
+return {
+  default_config = {
+    cmd = { 'lean-language-server', '--stdio', '--', '-M', '4096', '-T', '100000' },
+    filetypes = { 'lean3' },
+    root_dir = function(fname)
+      -- check if inside elan stdlib
+      local stdlib_dir
+      do
+        local _, endpos = fname:find(util.path.sep .. util.path.join('lean', 'library'))
+        if endpos then
+          stdlib_dir = fname:sub(1, endpos)
+        end
+      end
+
+      return util.root_pattern 'leanpkg.toml'(fname)
+        or util.root_pattern 'leanpkg.path'(fname)
+        or stdlib_dir
+        or util.find_git_ancestor(fname)
+    end,
+    single_file_support = true,
+  },
+  docs = {
+    description = [[
+https://github.com/leanprover/lean-client-js/tree/master/lean-language-server
+
+Lean installation instructions can be found
+[here](https://leanprover-community.github.io/get_started.html#regular-install).
+
+Once Lean is installed, you can install the Lean 3 language server by running
+```sh
+npm install -g lean-language-server
+```
+
+Note: that if you're using [lean.nvim](https://github.com/Julian/lean.nvim),
+that plugin fully handles the setup of the Lean language server,
+and you shouldn't set up `lean3ls` both with it and `lspconfig`.
+    ]],
+    default_config = {
+      root_dir = [[root_pattern("leanpkg.toml") or root_pattern(".git") or path.dirname]],
+    },
+  },
+}