duso-tree-sitter

A complete Tree-sitter grammar for the Duso scripting language.

Features

This grammar provides full parsing support for Duso syntax, including:

• Variables and assignments: Variable declarations, assignments, compound assignments
• Data types: Numbers, strings (with template expressions), multiline strings, booleans, nil, arrays, objects
• Control flow: if/elseif/else, while loops, numeric and iterator for loops, try/catch
• Functions: Function declarations, anonymous functions, closures
• Operators: Arithmetic, comparison, logical, assignment
• Built-in functions: All Duso built-ins (print, len, map, filter, etc.)
• Comments: Line comments (//) and block comments (/* */)
• Template expressions: Inline {{}} expressions in strings

Installation

Requirements

• Node.js 12.0 or higher
• tree-sitter-cli (for development)

Quick Setup

npm install --ignore-scripts
npm run generate

Full Build (with Node bindings)

npm install
npm run build

Usage

With tree-sitter CLI

Parse a Duso file:

tree-sitter parse example.du

Run tests:

npm test

With Neovim

Add to your Neovim configuration:

local parser_config = require "nvim-treesitter.parsers".get_parser_configs()

parser_config.duso = {
  install_info = {
    url = "https://github.com/duso-org/tree-sitter-duso",
    files = {"src/parser.c"},
    branch = "main",
  },
  filetype = "du",
}

Then install with :TSInstall duso and enable highlighting/indentation/etc.

With Helix

Add to languages.toml:

[[language]]
name = "duso"
scope = "source.duso"
file-extensions = ["du"]
roots = []

[language.indent]
tab-width = 2
unit = "  "

With Other Editors

Most editors with tree-sitter support (VS Code with tree-sitter extension, Emacs, etc.) can use this grammar. Refer to your editor's tree-sitter documentation.

Grammar Structure

The grammar is organized into the following main categories:

Statements

• Function declarations
• Control flow (if, while, for, try)
• Variable and assignment statements
• Return, break, continue

Expressions

• Binary operations (arithmetic, comparison, logical)
• Unary operations
• Function calls
• Array and object indexing/access
• Literals (strings, numbers, booleans, collections)

Built-in Functions

All Duso built-in functions are recognized:

abs, acos, asin, atan, atan2, append_file, breakpoint, busy, ceil, clamp, contains, context, copy_file, cos, current_dir, datastore, decode_base64, deep_copy, doc, encode_base64, ends_with, env, exit, exp, fetch, file_exists, file_type, filter, find, floor, format_json, format_time, hash, hash_password, http_server, include, input, join, keys, kill, len, list_dir, list_files, load, log, ln, lower, make_dir, map, markdown_ansi, markdown_html, markdown_text, max, min, move_file, now, parallel, parse, parse_json, parse_time, pi, pop, pow, print, push, random, range, reduce, remove_dir, remove_file, rename_file, replace, repeat, require, round, run, save, shift, sin, sleep, sort, spawn, split, sqrt, starts_with, substr, sys, tan, template, throw, tobool, tonumber, tostring, trim, type, unshift, upper, uuid, values, verify_password, watch, write

Testing

Test cases are located in test/corpus/basics.txt and use tree-sitter's test format.

Run tests with:

npm test

Queries

The following query files are included:

• highlights.scm - Syntax highlighting for supported editors
• locals.scm - Variable scope and binding information
• tags.scm - Tags for code navigation

Development

Regenerating Parser

After modifying grammar.js:

tree-sitter generate
npm run build

Testing Changes

tree-sitter test
# or
npm test

Debugging the Grammar

tree-sitter parse --debug example.du

Contributing

We'd love your contributions!

Related Projects

• Duso Language - The main Duso repository

License

© 2026 Ludonode LLC | Licensed under Apache License 2.0