helios-language-server

Language server for Helios, a non-Haskell Cardano smart contract language. Uses the pygls lsp framework and tree-sitter for syntax tree generation.

Requirements

• Python >=3.7
• python3-pip (Ubuntu/Debian)
• python3-venv (Ubuntu/Debian)

Installation

coc.nvim

1. Easy way via npm package coc-helios:

   :CocInstall coc-helios

2. Alternatively, if you know how to set up Python virtual environments:

   python3 -m venv .venv
source .venv/bin/activate
pip install helios-language-server

   Put this in your coc-settings.json file (:CocConfig):

   {
       "languageserver": {
         "helios": {
           "command": "helios-language-server",
           "args": ["--stdio"],
           "filetypes": ["*.hl", "hl"]
       }
   }

   The language server should now activate whenever you open .hl files, provided you have filetype.nvim plugin installed.

VSCode

  See vscode-helios.

Capabilities

• Auto-completions
• Hover
• Signature help
• Syntax errors
• Go to definition

Comments

Currently only supports builtin types and methods up until Helios v0.9.2 (apart from import statements).

While in general the tree-sitter parser works okay, there are several shortcomings as it is not always error tolerant. Meaning that if there are syntax errors present in the source code, the parser can sometimes generate error nodes spanning the entire document. This may lead to no/unexpected auto-completions. Unfortunately, not too much can be done about the parser's error recovery ability at this stage, as this is still also an open issue with tree-sitter. I have tried to address some commonly occuring parsing errors.

To-dos

• Parser improvements
• Advanced diagnostics
• Semantic highlighting
• Imports
• Go to definition
• Support newer Helios versions
• Tree-sitter syntax highlighting (nvim)
• Type checking