ecma-syntax-cat

ECMAScript abstract syntax tree as comp-cat-rs-idiomatic Rust types. ESTree-shaped, ES2024-complete, no panics, no Rc/Arc/RefCell, no interior mutability, no unsafe.

This is the foundation crate of a multi-crate comp-cat-rs reformulation of a JavaScript engine targeting Tauri integration. Five preceding falsification spikes (lambda-cat, lambda-ref-cat, lambda-obj-cat, lambda-throw-cat, lambda-async-cat) confirmed the idioms scale to every JS-distinctive runtime concern; this crate is the construction-phase artifact that defines the AST contract downstream crates build against.

Shape

Every AST node carries source-span information via Spanned<T>.
Recursive positions use Box<T> for indirection; collections use Vec<T>.
Variants follow ESTree naming, shortened to their core noun when used as enum variants.
Operators are factored into separate enums (BinaryOperator, LogicalOperator, UnaryOperator, UpdateOperator, AssignmentOperator) rather than expanded into the expression variants.

Coverage

ES2024 surface: literals (number, string, boolean, null, BigInt, regex, template), identifiers, all expression and statement forms, classes (including private fields, static blocks, getters/setters), modules (import/export), async/await, generators, destructuring, optional chaining, nullish coalescing, dynamic import, meta-property.

Excluded: TypeScript syntax, JSX, stage-3 proposals (decorators, pipeline operator) that have not yet finalized.

Usage

# fn main() -> Result<(), ecma_syntax_cat::error::Error> {
use ecma_syntax_cat::expression::{Expression, ExpressionKind};
use ecma_syntax_cat::identifier::Identifier;
use ecma_syntax_cat::literal::Literal;
use ecma_syntax_cat::operator::BinaryOperator;
use ecma_syntax_cat::span::Span;

let span = Span::synthetic();
let x = Expression::new(
    ExpressionKind::Identifier(Identifier::new("x")?),
    span,
);
let one = Expression::new(
    ExpressionKind::Literal(Literal::number(1.0)),
    span,
);
let plus = Expression::new(
    ExpressionKind::Binary {
        operator: BinaryOperator::Add,
        left: Box::new(x),
        right: Box::new(one),
    },
    span,
);
println!("{plus}");
# Ok(())
# }

Building

cargo build
cargo test
RUSTFLAGS="-D warnings" cargo clippy --all-targets

License