parser_and_other_editor_tools.md

title
Parser and other editor tools

Parser and other editor tools

Hi! There is a lot of space to grow in this area, and the development is somewhat spaced in time, so I (@AucaCoyan) decided to make a document explaining the framework, conventions and other required knowledge to help others and myself with this section.

Parser

The most important piece of this chapter is the parser. The parser is the bridge between the *.nu text files and the internal representation of object in nushell. Almost everything in this chapter interacts or is affected by the parser.

Current status

The current production parser is not bad at all, but it has certain areas that some improvement that could be greately appreciated. Sophia started a new parser and it's still on the works. The central idea of this new parser is that it will have multiple passes over the text, improving the typing structures by a lot.

Formatter

We have nufmt, but is a little stagnated because it will probably need some rework after the new parser is landed. The current issue is a bug reading stdin from the cmdline. Ask @AucaCoyan anything!

LSPs

LSP stands for Language Server Protocol, a Microsoft document to establish communication between text editors and parsers and other tools.

We currently have 2 of them, one for VS Code and one for other terminal editors

VSCode

This has it's own extension and it's the most advanced LSP. It was the first to appear it is bootstraped from a prototype of Microsoft. It's written in Typescript and interacts with nu in the command line to have:

• hover
• go to definition
• auto-completions

nu-lsp

This is a newer LSP that we would like to have as the long term for every editor . It's written in rust and it's on the nushell/nushell repo, in the crates/nu-lsp folder. Interacts via stdin and stdout and it is useful for vim, neovim, helix and other text editors. Sadly, it doesn't have the same level of features of VSCode-nushell-lang, that's why we still can't replace it.

Tree-sitter

We have another grammar: tree-sitter nushell this is useful for terminal text editors (nvim, helix, etc). VS Code doesn't have support for tree-sitter and its grammar is written in tmLanguage It has the following goals:

• Ability to serve as a parser for a repl
• Ability to work in editors that support tree-sitter (hx, nvim, others)
• Ability to work in rust
• Fast
• Ability to be utilized for syntax highlighting

I dont know a thing about all this, can you give me a hint on where to start?

Sure! you can begin with these resources:

• Adrian Hesketh gives an excellent talk about how LSP works
• TeeJ explains tree-sitter in a 15 min video
• about the formatter:
  • Bob Nystrom worked with the dart formatter and wrote a precious blog post about his journey. The hackernews post is also useful for the comments!
  • and a short overall view of how prettier works