Crate texter

Texter

Texter is a crate aiming to simplify writing an LSP using tree-sitter whilst benefiting from incremental updates. The main type that you will interacte with is Text.

Usage with lsp-types

change::Change implements From<lsp_types::TextDocumentContentChangeEvent> so in most cases calling Into::into and providing it to Text::update is enough to keep content in sync.

Selecting an encoding

Positions provided from a client may be for different encodings. UTF-8, UTF-16, or UTF-32. When starting up an LSP, the client provides encoding it will use. With that information we can store a function pointer and create new Text’s as needed.

The example below works the same way to how it is done in rust-analyzer.

use texter::core::text::Text;
use texter::lsp_types::PositionEncodingKind;

fn decide_encoding() -> fn(String) -> Text {
    // The type provided in client capabilities.
    let encodings: Option<Vec<PositionEncodingKind>> = get_client_encoding();
    let Some(encodings) = encodings else {
        return Text::new_utf16;
    };

    // Hope that we can use anything other than UTF-16
    for encoding in encodings {
        if encoding == PositionEncodingKind::UTF8 {
            return Text::new;
        } else if encoding == PositionEncodingKind::UTF32 {
            return Text::new_utf32;
        }
    }

    // Too bad, UTF-16 it is.
    Text::new_utf16
}

How to write an LSP using the crate?

There is multiple ways to structure your server, texter aims to influence the structure as little as possible. For an example you can check out trunkls.

Usage with tree-sitter

When using a Text with incremental updates we want to keep using a single tree_sitter::Tree across edits. To simplify the process Updateable is implemented on tree_sitter::Tree. So simply providing a mutable reference of the tree to a Text’s update method is enough to keep the data in sync.

In case you want to update a tree_sitter::Node, Updateable is implemented for it as well.

Re-exports

pub use lsp_types;lsp-types

pub use tree_sitter;tree-sitter

Modules

change

A module containing the basic items to perform a change.

core

The core functionality of the crate.

error

updateables