clojure-lsp

A Language Server for Clojure. Taking a Cursive-like approach of statically analyzing code.

What is this?

The goal of this project is to bring great editing tools for Clojure to all editors. It aims to work alongside you to help you navigate, identify and fix errors, and perform refactorings.

You will get:

• Autocomplete
• Jump to definition
• Find usages
• Renaming
• Errors
• Automatic ns management
• Refactorings

This is an early work in progress, contributions are very welcome.

Installation

• You need java on your $PATH.
• Grab the latest clojure-lsp from github LATEST
• Place it in your $PATH with a chmod 755
• Follow the documentation for your editor's language client. See Clients below.

NixOS

clojure-lsp is available in the nixpkgs:

nix-shell -p clojure-lsp

Troubleshooting

See troubleshooting.md.

Capabilities

capability	done	notes
completionProvider	√
referencesProvider	√
renameProvider	√
definitionProvider		TODO: java classes
diagnostics	√
hover	√
formatting	√
workspace-symbols	√
document-symbols	√
document-highlight	√

Refactorings

It should be possible to introduce most of the refactorings here: https://github.com/clojure-emacs/clj-refactor.el/tree/master/examples Calling executeCommand with the following commands and additional args will notify the client with applyEdit. All commands expect the first three args to be [document-uri, line, column] (eg ["file:///home/snoe/file.clj", 13, 11])

done	command	args	notes
√	add-missing-libspec
-	clean-ns
√	cycle-coll
√	cycle-privacy
√	expand-let
√	extract-function	[document-uri, line, column, function-name]
√	inline-symbol
√	introduce-let	[document-uri, line, column, binding-name]
√	move-to-let	[document-uri, line, column, binding-name]
√	thread-first
√	thread-first-all
√	thread-last
√	thread-last-all
√	unwind-all
√	unwind-thread

See Vim client section for an example.

Other clients might provide a higher level interface to workspace/executeCommand you need to pass the path, line and column numbers.

InitializationOptions

It is possible to pass some options to clojure-lsp through clients' InitializationOptions. Options are a map with keys:

source-paths value is a vector of project-local directories to look for clj/cljc/cljs files. Default is ["src","test"].

ignore-classpath-directories if true, will not consider clojure files within the directories specified by your classpath. This is needed, for instance, if your build puts artifacts into resources or target that you want lsp to ignore.

use-metadata-for-privacy? if true, will use ^:private metadata for refactorings instead of defn-

keep-require-at-start? if true, will keep first require at the first line instead of inserting a new line before it.

dependency-scheme by default, dependencies are linked with vim's zipfile://<zipfile>::<innerfile> scheme, however you can use a scheme of jar to get urls compatible with java's JarURLConnection. You can have the client make an lsp extension request of clojure/dependencyContents with the jar uri and the server will return the jar entry's contents. Similar to java clients

cljfmt json encoded configuration for https://github.com/weavejester/cljfmt

"cljfmt": {
  "indents": {
    "#.*": [["block", 0]],
    "ns": [["inner", 0], ["inner", 1]],
    "and": [["inner", 0]],
    "or": [["inner", 0]],
    "are": [["inner", 0]]
}},

linters some initial support for disabling diagnostics currently only this one that will suppress the unused alias warning and stop the require from being cleaned by clean-ns:

 "linters" {:unused-namespace {:exclude [clojure.data]}}

project-specs value is a vector containing a map of key/value pairs, for example:

"initializationOptions": {
    "project-specs": [{
        "project-path": "deps.edn",
        "classpath-cmd": ["clj", "-Spath"]}]
    }

Note: You may also consider configuring project specs via the (optional) .lsp/config.edn file, i.e.,

{"project-specs" [{:project-path "deps.edn"
                   :classpath-cmd ["clj" "-Spath"]}]}

Each project-spec will add to the list of dependencies for lsp to crawl:

• project-path is the required filename used by your build tool (project.clj, build.boot, deps.edn, package.json, etc)
• classpath-cmd is the required vector of commands to get your project's classpath string (e.g. ["clj", "-Spath"])
• env optionally add environment variables to the classpath-cmd (e.g. {"BOOT_FILE": "x.boot"})

macro-defs

macro-defs value is a map of fully-qualified macros to a vector of definitions of those macros' forms.

Element definitions

Elements can be defined in two ways:

• A simple keyword, e.g. :declaration

• A map that includes the element type and options, e.g. {:element :declaration, :tags ["unused" "local"], :signature ["next"]}

Element types

Valid element definitions are:

• declaration This marks a symbol or keyword as a definition/declaration of a var in the current namespace.

  • In the simplest case, this element can be specified as the keyword :declaration.
  • You can customize the behavior of the declaration by making it a map.
    • e.g. {:element :declaration, :tags ["unused" "local"], :signature ["next"]}
    • tags are optional.
      • The unused tag supresses the "unused declaration" diagnostic, useful for deftest vars.
      • The local tag marks the var as private.
    • signature is optional. If the macro has defn-like bindings, this vector of movements should point to the parameter vector or the first var arg list form. Only next is supported right now.
  • e.g. (my-defn- my-name "docstring" [& params] (count params)) => {my.ns/my-defn- [{"element": "declaration", "tags", ["local"], "signature": ["next" "next"]}]}

• bindings This marks let and for-like bindings. bound-elements will have these bindings in their scope.

  • e.g. (my-with-open [resource ()] ....) => {my.ns/my-with-open ["bindings", "bound-elements"]}

• function-params-and-bodies This will parse function like forms that support optional var-args like fn.

  • e.g. (myfn ([a] ...) ([b] ...)) (myfn [c] ...) => {my.ns/myfn ["function-params-and-bodies"]}

• params This marks a defn like parameter vector. bound-elements will have these parameters in their scope.

  • e.g. (myfn [c] ...) => {my.ns/myfn ["params", "bound-elements"]}

• param This marks a single defn like parameter. bound-elements will have these parameters in their scope.

• elements This will parse the rest of the elements in the macro form with the usual rules.

  • e.g. (myif-let [answer (expr)] answer (log "no answer") "no answer") => {my.ns/myif-let ["bindings", "bound-element", "elements"]}

• element This will parse a single element in the macro form with the usual rules.

  • In the simplest case, element can be specified as the keyword :element. This will always parse a single element.
  • You can make the element optional by making it a map that includes a predicate pred which will determine whether the current form is parsed as an element, or if the element should be skipped and the current form parsed as the next defined element.
  • For example, you can define an optional docstring element as {:element :element, :pred :string}, or an optional metadata map as {:element :element, :pred :map}.
  • element can also describe repeated elements. For example, {:element :element, :pred :string, :repeat true} will parse 1 or more strings.
  • element can also describe multiple elements of different types. This is useful, for example, if you have a macro like adzerk.env/def whose arguments are pairs of declarations and values:
    • (adzerk.env/def FOO :required, BAR nil, BAZ "string") => {adzerk.env/def [{:element [:declaration :element], :repeat true}]}

• bound-elements This will parse the rest of the elements in the macro form with the usual rules but with any bindings or params in scope.

• bound-element This will parse a single element in the macro form with the usual rules but with any bindings or params in scope.

See https://github.com/snoe/clojure-lsp/blob/master/test/clojure_lsp/parser_test.clj for examples.

Project Settings

LSP will also look for project specific settings in a file called '.lsp/config.edn'. It will search from your root folder up the directory structure so you can have multiple projects share the settings.

{"macro-defs" {korma.core/defentity [:declaration :elements]}
 "cljfmt" {:indents {#re ".*" ns [[:inner 0] [:inner 1]]}}}

Clients

Clients are either editors with built in LSP support like Oni, or an appropriate plugin. Clients are responsible for launching the server, the server is a subprocess of your editor not a daemon.

In general, make sure to configure the client to use stdio and a server launch command like ['/usr/local/bin/clojure-lsp']. If that fails, you may need to have your client launch inside a shell, so use someting like ['bash', '-c', '/usr/local/bin/clojure-lsp']. In windows you probably need to rename to clojure-lsp.bat.

Vim

I prefer https://github.com/neoclide/coc.nvim but both http://github.com/autozimu/LanguageClient-neovim and https://github.com/prabirshrestha/vim-lsp work well.

See my nvim/init.vim and coc-settings.json

LanguageClient-neovim can be configure with:

Refactorings:

function! Expand(exp) abort
    let l:result = expand(a:exp)
    return l:result ==# '' ? '' : "file://" . l:result
endfunction

nnoremap <silent> crcc :call LanguageClient#workspace_executeCommand('cycle-coll', [Expand('%:p'), line('.') - 1, col('.') - 1])<CR>
nnoremap <silent> crth :call LanguageClient#workspace_executeCommand('thread-first', [Expand('%:p'), line('.') - 1, col('.') - 1])<CR>
nnoremap <silent> crtt :call LanguageClient#workspace_executeCommand('thread-last', [Expand('%:p'), line('.') - 1, col('.') - 1])<CR>
nnoremap <silent> crtf :call LanguageClient#workspace_executeCommand('thread-first-all', [Expand('%:p'), line('.') - 1, col('.') - 1])<CR>
nnoremap <silent> crtl :call LanguageClient#workspace_executeCommand('thread-last-all', [Expand('%:p'), line('.') - 1, col('.') - 1])<CR>
nnoremap <silent> crml :call LanguageClient#workspace_executeCommand('move-to-let', [Expand('%:p'), line('.') - 1, col('.') - 1, input('Binding name: ')])<CR>
nnoremap <silent> cril :call LanguageClient#workspace_executeCommand('introduce-let', [Expand('%:p'), line('.') - 1, col('.') - 1, input('Binding name: ')])<CR>
nnoremap <silent> crel :call LanguageClient#workspace_executeCommand('expand-let', [Expand('%:p'), line('.') - 1, col('.') - 1])<CR>
nnoremap <silent> cram :call LanguageClient#workspace_executeCommand('add-missing-libspec', [Expand('%:p'), line('.') - 1, col('.') - 1])<CR>

InitializationOptions can be sent by setting: let g:LanguageClient_settingsPath=".lsp/settings.json"

Project-local .lsp/settings.json would have content like:

{"initializationOptions": {
   "source-paths": ["shared-src", "src", "test", "dashboard/src"],
   "macro-defs": {project.macros/dofor: ["bindings", "bound-elements"]}}}

Oni

Seems to work reasonably well but couldn't get rename to work reliably https://github.com/onivim/oni

Intellij / Cursive

https://github.com/gtache/intellij-lsp tested only briefly.

vscode

Proof of concept in the client-vscode directory in this repo.

atom

I tried making a client but my hello world attempt didn't seem to work. If someone wants to take this on, I'd be willing to package it here too.

emacs

lsp-mode has built in support for clojure-lsp since lsp-mode-20190416.1936. With use-package add the following to your emacs config:

(use-package lsp-mode
  :ensure t
  :hook ((clojure-mode . lsp)
         (clojurec-mode . lsp)
         (clojurescript-mode . lsp))
  :config
  ;; add paths to your local installation of project mgmt tools, like lein
  (setenv "PATH" (concat
                   "/usr/local/bin" path-separator
                   (getenv "PATH")))
  (dolist (m '(clojure-mode
               clojurec-mode
               clojurescript-mode
               clojurex-mode))
     (add-to-list 'lsp-language-id-configuration `(,m . "clojure")))
  (setq lsp-enable-indentation nil
        lsp-clojure-server-command '("bash" "-c" "clojure-lsp")))

Optionally you can add lsp-ui and company-lsp too:

(use-package lsp-ui
  :ensure t
  :commands lsp-ui-mode)

(use-package company-lsp
  :ensure t
  :commands company-lsp)

In order to make the jumping into dependency jars work you have to have a config.edn in your project-dir/.lsp directory (or higher in the directory hierarchy) with the right dependency-scheme so the server returns an URI emacs-lsp can process:

{"dependency-scheme" "jar"}

In lsp-mode lsp-clojure-server-command defcustom is available to override the command to start the clojure-lsp server, might be necessary to do this on a Windows environment.

TODO

Diagnostics

• configuration (see joker lint options)

Others

• Better completion item kinds and auto require
• other lsp capabilities?

Building local

For building local, run lein bin to generate the binary inside target folder.