parseOn method

@override Result<String> parseOn(Context context)

Primitive method doing the actual parsing.

The method is overridden in concrete subclasses to implement the parser specific logic. The methods takes a parse context and returns the resulting context, which is either a Success or Failure context.

Implementation

@override
Result<String> parseOn(Context context) {
  final buffer = context.buffer;
  final position = context.position;
  if (position < buffer.length) {
    switch (buffer.codeUnitAt(position)) {
      case 10:
        // Unix and Unix-like systems (Linux, macOS, FreeBSD, AIX, Xenix, etc.),
        // Multics, BeOS, Amiga, RISC OS.
        return context.success('\n', position + 1);
      case 13:
        if (position + 1 < buffer.length &&
            buffer.codeUnitAt(position + 1) == 10) {
          // Microsoft Windows, DOS (MS-DOS, PC DOS, etc.), Atari TOS, DEC
          // TOPS-10, RT-11, CP/M, MP/M, OS/2, Symbian OS, Palm OS, Amstrad
          // CPC, and most other early non-Unix and non-IBM operating systems.
          return context.success('\r\n', position + 2);
        } else {
          // Commodore 8-bit machines (C64, C128), Acorn BBC, ZX Spectrum,
          // TRS-80, Apple II series, Oberon, the classic Mac OS, MIT Lisp
          // Machine and OS-9
          return context.success('\r', position + 1);
        }
    }
  }
  return context.failure(message);
}