module.exports = grammar({
  name: 'hack_binary',

  rules: {
    source_file: $ => repeat($._item),

    _item: $ => choice(
      $.binary_instruction,
      $.comment,
      $._whitespace
    ),

    // 16-bit binary instruction
    binary_instruction: $ => $.bit_sequence,

    // 16-bit sequence of 0s and 1s
    bit_sequence: $ => /[01]{16}/,

    // Comments
    comment: $ => token(seq('//', /.*/)),

    // Whitespace
    _whitespace: $ => /\s+/
  },

  extras: $ => [
    /\s/,
    $.comment
  ]
});