Tremor Language Server (Trill)

WIP server for use with editors and IDEs, when working with tremor's languages. Follows language server protocol.

Features

Diagnostics

tremor-script interpreter errors (as you type or on file save), with hints for fixing (as applicable)

nice-to-have: apply fix suggestions from errors

Completion

code completion (as you type/on-demand) for module functions -- function names with signature/doc info as well as placeholders for arguments.

nice-to-have: code completion for variables as well as other language constructs

Hover

diagnostics and function documentation on mouse hover (or editor command)

nice-to-have: documentation for variables (eg: assignment info)

Navigation

nice-to-have: find all references, symbol search

for later: Go to definiton, peek definition, symbol list (when tremor script has functions)

Refactoring

nice-to-have: rename all references

Quickstart

For installation:

cargo install tremor-language-server

Make sure .cargo/bin is in your $PATH (or install it somewhere in your $PATH via cargo).

If you are developing on the language server:

git clone git@github.com:tremor-rs/tremor-language-server.git
cd tremor-language-server

# build and link somewhere in your path (for easy access/use in testing via editors)
cargo build
ln -s target/debug/tremor-language-server ~/bin/ # or anywhere in your $PATH

# to install the release build
cargo install --path . --root ~/ # make sure ~/bin/ is in your $PATH

VS Code setup

Follow instructions at:

https://github.com/tremor-rs/tremor-vscode

Vim setup

Prerequisite: install https://github.com/tremor-rs/tremor-vim so that vim is aware of tremor filetypes (you also get syntax highlighting as a bonus).

ale

For use with vim, we have a forked version of ale that can interact with the tremor language server:

https://github.com/anupdhml/ale/tree/tremor

Follow the plugin installation instructions. If you are using vim-plug, this will do:

Plug 'anupdhml/ale', { 'branch': 'tremor' }

Vim and ale settings that work nice with the tremor language server:

" completion menu
set completeopt=menuone,longest,popup " always show the menu, insert longest match, use popup window for extra info
"set completepopup=border:off          " remove the border from the completion popup window

" turn on omnicomplete based on ale
set omnifunc=ale#completion#OmniFunc

" enable ale completion (as you type), where available
"let g:ale_completion_enabled = 1

" turn on vim mouse support in all modes (for hover info)
set mouse=a

" show hover information on mouse over (vim mouse support should be turned on)
" xterm2 makes hover work with tmux as well
let g:ale_set_balloons = 1
set ttymouse=xterm2

" only run linters named in ale_linters settings
let g:ale_linters_explicit = 1

" active linters
let g:ale_linters = {
\   'tremor': ['tremor-language-server'],
\   'trickle': ['tremor-language-server'],
\}

" when to run linting/fixing. choose as desired
"
" aggressive
let g:ale_fix_on_save = 1
let g:ale_lint_on_text_changed = 'always'
let g:ale_lint_on_enter = 1
let g:ale_lint_on_insert_leave = 1
"
" conservative
"let g:ale_lint_on_text_changed = 'never'
"let g:ale_lint_on_enter = 0
"let g:ale_lint_on_insert_leave = 0

" key mappings
nmap <silent> <leader>j <Plug>(ale_next_wrap)
nmap <silent> <leader>k <Plug>(ale_previous_wrap)
nmap <silent> <leader>/ <Plug>(ale_hover)
nmap <silent> <leader>? <Plug>(ale_detail)
nmap <silent> <leader>] <Plug>(ale_go_to_definition)
nmap <silent> <leader># <Plug>(ale_find_references)

You might want to show ALE counters in your vim status line. If you are using vim lightline:

" for showing linter errrors/warnings. depends on lightline-ale
let g:lightline.component_expand = {
    \  'linter_checking': 'lightline#ale#checking',
    \  'linter_warnings': 'lightline#ale#warnings',
    \  'linter_errors': 'lightline#ale#errors',
    \  'linter_ok': 'lightline#ale#ok',
    \ }
let g:lightline.component_type = {
    \  'linter_checking': 'left',
    \  'linter_warnings': 'warning',
    \  'linter_errors': 'error',
    \  'linter_ok': 'left',
    \ }
let g:lightline#ale#indicator_checking = ''
let g:lightline#ale#indicator_warnings = '▲'
let g:lightline#ale#indicator_errors = '✗'
let g:lightline#ale#indicator_ok = '✓'

" configure lightline components
let g:lightline.active = {
    \   'left':  [ ['mode', 'paste'],
    \              ['fugitive', 'readonly', 'filename', 'modified'] ],
    \   'right': [ [ 'lineinfo' ],
    \              [ 'percent' ],
    \              [ 'fileformat', 'fileencoding', 'filetype' ],
    \              ['linter_checking', 'linter_errors', 'linter_warnings', 'linter_ok' ] ]
    \ }

" ale indicators (aligned with indicators used in lightline-ale)
" 2 chars to cover the full sign width
let g:ale_sign_warning = '▲▲'
let g:ale_sign_error = '✗✗'

For more ale setup and vim configuration:

https://github.com/anupdhml/dotfiles/blob/virtualbox_new/data/.vimrc

coc-nvim

Install coc.nvim as described in their README.

Start vim and enter :CocConfig and enter the following as additional entry:

{
  "tremor": {
    "command": "tremor-language-server",
    "fileTypes": ["tremor", "trickle"]
  }
}

Other VIM language server clients

If you prefer not to use ale or coc-nvim, these vim plugins should also work well as the server client:

Notes

If you are using vim from terminal and not seeing error diagnostics or function docs on hover, check if the vim version you are using has been compiled with balloon support -- output of vim --version should show items +balloon_eval and +balloon_eval_term. If not, you will need to find a vim package for your environment with the support baked in (or compile vim yourself). Eg: for mac, this may mean installing macvim via homebrew.
By default, vim's omni-completion items (eg: tremor function names after typing module_name::) are triggered via Ctrl-x Ctrl-o, while normal keyword completion is via Ctrl-p/Ctrl-n. If you prefer a more accessible keybinding for these (eg: Tab), have a look at extensions like VimCompletesMe, or Supertab.

TODO

integration for emacs
support parallel edits for trickle and tremor files
improve debugging
add tests
ability to handle multiple script errors
use simd-json in tower and json rpc crates?
distribution without compiling

PrimalPimmy/tremor-language-server