tree-sitter-angelscript

A tree-sitter grammar for the AngelScript scripting language.

Provides parsing, syntax highlighting, and code navigation for AngelScript .as files in any editor or tool that supports tree-sitter.

Features

Language coverage

The grammar covers the full AngelScript syntax:

• Declarations - classes (with inheritance, abstract/final/shared modifiers), interfaces, enums, namespaces, mixins, typedefs, funcdefs, imports, using directives
• Functions - declarations, constructors, destructors, forward declarations, parameter modifiers (in, out, inout), default values, variadic parameters, function attributes (override, final, explicit, property, delete)
• Types - primitives (int, float, bool, string, etc.), templates (Array<T>), handles (@), const qualifiers, auto type, scoped types (Mod::Type), arrays (int[])
• Statements - if/else, for, foreach, while, do-while, switch/case, try/catch, return, break, continue
• Expressions - full operator precedence (15 levels), assignment operators, ternary, logical (&&, ||, ^^, and, or, xor), bitwise, identity (is, !is), exponentiation (**), unsigned right shift (>>>), handle-of (@), prefix/postfix increment/decrement, member access, indexing (with named indices), function calls (with named arguments), cast expressions, lambda expressions
• Literals - integers (decimal, hex 0xFF, octal 0o77, binary 0b1010), floats (with exponent and suffix), single/double quoted strings, triple-quoted heredoc strings, booleans, null
• Virtual properties - get/set accessors with const and attribute support
• Comments - single-line (//) and block (/* */)

External scanner

An external scanner (src/scanner.c) handles template <> disambiguation, distinguishing generic types like Array<int> from comparison operators. It tracks template nesting depth and uses heuristics to determine whether < opens a template argument list or is a less-than operator.

Query files

File	Purpose
queries/highlights.scm	Syntax highlighting -- keywords, types, functions, literals, operators, punctuation
queries/tags.scm	Code navigation -- symbol definitions (functions, classes, interfaces, enums, namespaces, properties) and references (function/method calls)

Test corpus

135 tests across 6 corpus files covering basics, declarations, expressions, functions, statements, and type system (including template disambiguation).

Usage

Rust

Add to Cargo.toml:

[dependencies]
tree-sitter-language = "0.1.7"
tree-sitter = "0.26.7"

use tree_sitter_angelscript::LANGUAGE;

let mut parser = tree_sitter::Parser::new();
parser.set_language(&LANGUAGE.into()).unwrap();

let source = "void main() { int x = 42; }";
let tree = parser.parse(source, None).unwrap();
println!("{}", tree.root_node().to_sexp());

The crate also exports HIGHLIGHTS_QUERY (the contents of queries/highlights.scm) and NODE_TYPES (the contents of src/node-types.json).

Node.js / CLI

npm install
npx tree-sitter generate
npx tree-sitter parse examples/sample.as
npx tree-sitter highlight examples/sample.as

Development

Prerequisites

• Node.js (for tree-sitter-cli)
• A C compiler (for the parser and external scanner)
• Rust toolchain (for the crate)

Build and test

# Install tree-sitter CLI
npm install

# Generate the parser from grammar.js
npx tree-sitter generate

# Run the test corpus (135 tests)
npx tree-sitter test

# Parse an example file (should produce zero ERROR nodes)
npx tree-sitter parse examples/sample.as

# Verify syntax highlighting
npx tree-sitter highlight examples/sample.as

# Build and test the Rust crate
cargo build
cargo test

Project structure

grammar.js              # Grammar definition (source of truth)
src/
  scanner.c             # External scanner for template <> disambiguation
  parser.c              # Generated parser (tracked for downstream consumers)
  lib.rs                # Rust crate FFI bindings
  node-types.json       # Generated node type metadata
  tree_sitter/parser.h  # Generated parser header
queries/
  highlights.scm        # Syntax highlighting queries
  tags.scm              # Code navigation queries
test/corpus/            # Test corpus (138 tests)
  basics.txt
  declarations.txt
  expressions.txt
  functions.txt
  statements.txt
  types.txt
examples/
  sample.as             # Comprehensive example for manual testing

License

The tree-sitter-angelscript published under BSD-3-Clause license. For more details read LICENSE file.