Crate swc_ecma_parser 

EcmaScript/TypeScript parser for the rust programming language.

Features

Heavily tested

Passes almost all tests from tc39/test262.

Error reporting

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.

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<SourceMap> = 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()).into(),
        "function foo() {}",
    );
    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");
}

Cargo features

typescript

Enables typescript parser.

verify

Verify more errors, using swc_ecma_visit.

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.

Re-exports

pub use lexer::Lexer;

Modules

error

input

lexer

ECMAScript lexer.

token

This module should only be used by [swc_ecma_lexer] for compatibility.

unstableunstable

This module expose tokens related to the swc_ecma_parser::lexer.

Macros

byte_search

declare_keyword

ident_like

known_ident

known_ident_token

safe_byte_match_table

Structs

Context

EsSyntax

Parser

EcmaScript parser.

ParserCheckpoint

StringInput

Implementation of Input.

SyntaxFlags

TsSyntax

Enums

Syntax

Traits

Input

Functions

parse_file_as_commonjs

Note: This is recommended way to parse a file.

parse_file_as_expr

Note: This is recommended way to parse a file.

parse_file_as_module

Note: This is recommended way to parse a file.

parse_file_as_program

Note: This is recommended way to parse a file.

parse_file_as_script

Note: This is recommended way to parse a file.

with_file_parser

Type Aliases

PResult