swc_ecma_parser 0.78.12

EcmaScript/TypeScript parser for the rust programming language. # Features ## Heavily tested Passes almost all tests from [tc39/test262][]. ## Error reporting ```sh error: 'implements', 'interface', 'let', 'package', 'private', 'protected', 'public', 'static', or 'yield' cannot be used as an identifier in strict mode --> invalid.js:3:10 | 3 | function yield() { | ^^^^^ ``` ## Error recovery The parser can recover from some parsing errors. For example, parser returns `Ok(Module)` for the code below, while emitting error to handler. ```ts const CONST = 9000 % 2; const enum D { // Comma is required, but parser can recover because of the newline. d = 10 g = CONST } ``` # Example (lexer) See `lexer.rs` in examples directory. # Example (parser) ``` #[macro_use] extern crate swc_common; extern crate swc_ecma_parser; use swc_common::sync::Lrc; use swc_common::{ errors::{ColorConfig, Handler}, FileName, FilePathMapping, SourceMap, }; use swc_ecma_parser::{lexer::Lexer, Parser, StringInput, Syntax}; fn main() { let cm: Lrc = Default::default(); let handler = Handler::with_tty_emitter(ColorConfig::Auto, true, false, Some(cm.clone())); // Real usage // let fm = cm // .load_file(Path::new("test.js")) // .expect("failed to load test.js"); let fm = cm.new_source_file( FileName::Custom("test.js".into()), "function foo() {}".into(), ); let lexer = Lexer::new( // We want to parse ecmascript Syntax::Es(Default::default()), // EsVersion defaults to es5 Default::default(), StringInput::from(&*fm), None, ); let mut parser = Parser::new_from(lexer); for e in parser.take_errors() { e.into_diagnostic(&handler).emit(); } let _module = parser .parse_module() .map_err(|mut e| { // Unrecoverable fatal error occurred e.into_diagnostic(&handler).emit() }) .expect("failed to parser module"); } ``` ## Known issues ### Null character after `\` Because [String] of rust should only contain valid utf-8 characters while javascript allows non-utf8 characters, the parser stores invalid utf8 characters in escaped form. As a result, swc needs a way to distinguish invalid-utf8 code points and input specified by the user. The parser stores a null character right after `\\` for non-utf8 code points. Note that other parts of swc is aware of this fact. Note that this can be changed at anytime with a breaking change. [tc39/test262]:https://github.com/tc39/test262