grammar.js

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

  inline: ($) => [$._statement],

  externals: ($) => [$.output_line],

  rules: {
    test_file: ($) => repeat(choice($.comment, $.test_case, $._statement)),

    _statement: ($) =>
      choice($.local_statement, $.exec_statement, $.if_statement),

    if_statement: ($) =>
      seq(
        '#@if',
        field('condition', $.gap_expression),
        repeat(choice($.comment, $.test_case)),
        optional($.else_clause),
        '#@fi',
        '\n',
      ),

    else_clause: ($) =>
      seq('#@else', '\n', repeat(choice($.comment, $.test_case))),

    local_statement: ($) => seq('#@local', $.gap_expression),

    exec_statement: ($) => seq('#@exec', $.gap_expression),

    test_case: ($) =>
      seq(
        'gap> ',
        alias($.gap_expression, $.input_line),
        repeat(
          choice(
            seq('> ', alias($.gap_expression, $.input_line)),
            $.output_line,
          ),
        ),
      ),

    comment: (_) => /\n?#([^@\n].*)?\n*/,
    gap_expression: (_) => /[^\n]*?\n?/,
  },
});