chevrotain/src/parse/exceptions_public.ts

Chevrotain is a high performance fault tolerant javascript parsing DSL for building recursive decent parsers

import { contains } from "../utils/utils"
import { IToken, IRecognitionException, IRecognizerContext } from "../../api"

const MISMATCHED_TOKEN_EXCEPTION = "MismatchedTokenException"
const NO_VIABLE_ALT_EXCEPTION = "NoViableAltException"
const EARLY_EXIT_EXCEPTION = "EarlyExitException"
const NOT_ALL_INPUT_PARSED_EXCEPTION = "NotAllInputParsedException"

const RECOGNITION_EXCEPTION_NAMES = [
  MISMATCHED_TOKEN_EXCEPTION,
  NO_VIABLE_ALT_EXCEPTION,
  EARLY_EXIT_EXCEPTION,
  NOT_ALL_INPUT_PARSED_EXCEPTION
]

Object.freeze(RECOGNITION_EXCEPTION_NAMES)

// hacks to bypass no support for custom Errors in javascript/typescript
export function isRecognitionException(error: Error) {
  // can't do instanceof on hacked custom js exceptions
  return contains(RECOGNITION_EXCEPTION_NAMES, error.name)
}

abstract class RecognitionException
  extends Error
  implements IRecognitionException {
  context: IRecognizerContext
  resyncedTokens = []

  protected constructor(message: string, public token: IToken) {
    super(message)

    // fix prototype chain when typescript target is ES5
    Object.setPrototypeOf(this, new.target.prototype)

    /* istanbul ignore next - V8 workaround to remove constructor from stacktrace when typescript target is ES5 */
    if (Error.captureStackTrace) {
      Error.captureStackTrace(this, this.constructor)
    }
  }
}

export class MismatchedTokenException extends RecognitionException {
  constructor(message: string, token: IToken, public previousToken: IToken) {
    super(message, token)
    this.name = MISMATCHED_TOKEN_EXCEPTION
  }
}

export class NoViableAltException extends RecognitionException {
  constructor(message: string, token: IToken, public previousToken: IToken) {
    super(message, token)
    this.name = NO_VIABLE_ALT_EXCEPTION
  }
}

export class NotAllInputParsedException extends RecognitionException {
  constructor(message: string, token: IToken) {
    super(message, token)
    this.name = NOT_ALL_INPUT_PARSED_EXCEPTION
  }
}

export class EarlyExitException extends RecognitionException {
  constructor(message: string, token: IToken, public previousToken: IToken) {
    super(message, token)
    this.name = EARLY_EXIT_EXCEPTION
  }
}