tmGrammar / editor support / LSP

[alensiljak]

To support editing the data files in editors (like vscode, for example), a tmGrammar file would be used.
I've noticed that this grammar is a bit limited (see here but would be helpful, nonetheless.
The question is - would this be useful for the parser, #11, at all?

Or, more generally, could the parser be used to support syntax highlighting in text editors?

[antage]

Yes and no. If the text is parsed correctly, you can highlight it with AST. However, if the text is invalid (for example, an unclosed transaction), the parser cannot help you.

[alensiljak]

I was thinking along the lines of - if a Regex can be written to recognize and highlight the syntax in an editor, can it then also be used to parse that syntax for an in-app parser? These are my first forays into parser territory so I apologize if it's a stupid question.

As for the parser - now it seems popular to have a language server, spewing errors while writing syntax. I don't see a reason why we shouldn't attempt something similar. At least to check for the syntax correctness.

Edit: one example is Rust's Analyzer. Since Rust is a compiled language, it's an interesting example. The plugin (not necessarily a language server) could run the application and report back any errors it reports.

[antage]

Regex in tmGrammar only highlights keywords and literals. It is not a full parser.

LSP is a good idea. Beancount VSCode extension has an LSP implementation. You can use it in VSCode and NeoVIM (maybe also in Emacs, I'm not sure).

Parsers for LSP and compilers are not the same thing. The Rust analyzer, for example, uses its own parser that can parse erroneous text. It has to parse the text when you're typing it.

[claytonrcarter]

LSP is a good idea

I've been hacking on a prototype LSP for ledger for an (also prototype) language extension for Zed. I just pushed it to https://gitlab.com/claytonrcarter/ledger-lsp if you're interested in checking it out.

The basic features that I have working are

• completions for payees and accounts (from current file only)
• format on save
• goto definition to support clicking on include $file to open $file

It's working on the files I've been using, but no guarantees that it will work on arbitrary files. While there's still a lot that could be done, added, cleaned up, it's doing 95% of what I need, so it's probably "done" for now. 😄

Parsers for LSP and compilers are not the same thing

☝️ I'm using a combination of ledger-parser, regex and tree-sitter-ledger to implement various features.