treesitter

Tree-sitter parsing and syntax analysis for the Wippy runtime, delivered as a self-contained WebAssembly module — no CGO, no native build tag.

A Rust component compiles the tree-sitter C runtime and its grammars to wasm32-wasip2 and runs resident inside the runtime's wazero engine. Each parse keeps its syntax tree in the component's linear memory keyed by an integer handle; parse returns the whole tree serialized once, and Node/Tree/Cursor navigation runs in pure Lua over that snapshot. Only parse, query, language, edit, and free cross into WebAssembly.

Supported languages

go (golang), javascript (js), typescript (ts), tsx, python (py), php, c# (csharp, cs), html (html5), lua, markdown (md), sql.

Usage

local treesitter = require("treesitter")

local tree = treesitter.parse("go", [[
package main

func hello() string {
    return "Hello, World!"
}
]])

local root = tree:root_node()
print(root:kind())  -- "source_file"

local query = treesitter.query("go", [[
    (function_declaration name: (identifier) @func_name)
]])

for _, capture in ipairs(query:captures(root, code)) do
    print(capture.name, capture.text)  -- "func_name", "hello"
end

local cursor = tree:walk()
cursor:goto_first_child()
print(cursor:current_node():kind())

cursor:close()
query:close()
tree:close()

Errors are structured: check err:kind() against errors.INVALID / errors.INTERNAL.

Building

The compiled engine (src/treesitter/assets/treesitter.wasm, ~12 MB) is not committed — it is a build artifact produced on demand. Build it before running, testing, or publishing the module:

make image            # build the wasi-sdk + rust image (once; requires Docker)
make build-component  # compile the Rust engine in docker, stage the .wasm, inject its sha256 into _index.yaml

build-component is reproducible (pinned wasi-sdk, rustup toolchain, and Cargo.lock), so it regenerates the exact bytes the committed _index.yaml hash expects. A host C/Rust toolchain is not required — everything compiles inside Docker.

First run end to end:

make image            # 1. build the toolchain image (once)
make build-component  # 2. produce src/treesitter/assets/treesitter.wasm
make wippy            # 3. point ./wippy at ../runtime/dist/wippy-<os>-<arch>
./wippy install       # 4. vendor test dependencies (wippy/test, wippy/terminal) into .wippy
make test             # 5. run the suites against the runtime
make check            # build-component + lint + test in one shot