grammar.js

module.exports = grammar({
  name: "yaml",

  externals: ($) => [
    $._eof,

    // s  = starts at column 0 in the current or following row
    // r  = starts with 0 or more s_white in the current row
    // br = starts with more than `current_indent` s_white in the following row
    // b  = starts with `current_indent` s_white in the following row
    // bl = starts with `parent_indent` or less s_white in the following row
    $._s_dir_yml_bgn,
    $._r_dir_yml_ver, // %YAML 1.2
    $._s_dir_tag_bgn,
    $._r_dir_tag_hdl,
    $._r_dir_tag_pfx, // %TAG !yaml! tag:yaml.org,2002:
    $._s_dir_rsv_bgn,
    $._r_dir_rsv_prm, // %FOO bar baz
    $._s_drs_end, // ---
    $._s_doc_end, // ...
    $._r_blk_seq_bgn,
    $._br_blk_seq_bgn,
    $._b_blk_seq_bgn, // -
    $._r_blk_key_bgn,
    $._br_blk_key_bgn,
    $._b_blk_key_bgn, // ?
    $._r_blk_val_bgn,
    $._br_blk_val_bgn,
    $._b_blk_val_bgn, // :
    $._r_blk_imp_bgn, // : (implicit)
    $._r_blk_lit_bgn,
    $._br_blk_lit_bgn, // |
    $._r_blk_fld_bgn,
    $._br_blk_fld_bgn, // >
    $._br_blk_str_ctn, // block scalar content
    $._r_flw_seq_bgn,
    $._br_flw_seq_bgn,
    $._b_flw_seq_bgn, // [
    $._r_flw_seq_end,
    $._br_flw_seq_end, // ]
    $._r_flw_map_bgn,
    $._br_flw_map_bgn,
    $._b_flw_map_bgn, // {
    $._r_flw_map_end,
    $._br_flw_map_end, // }
    $._r_flw_sep_bgn,
    $._br_flw_sep_bgn, // ,
    $._r_flw_key_bgn,
    $._br_flw_key_bgn, // ?
    $._r_flw_jsv_bgn,
    $._br_flw_jsv_bgn, // : (json key)
    $._r_flw_njv_bgn,
    $._br_flw_njv_bgn, // : (non-json key)
    $._r_dqt_str_bgn,
    $._br_dqt_str_bgn,
    $._b_dqt_str_bgn, // " (start)
    $._r_dqt_str_ctn,
    $._br_dqt_str_ctn, // double quote scalar content
    $._r_dqt_str_end,
    $._br_dqt_str_end, // " (end)
    $._r_sqt_str_bgn,
    $._br_sqt_str_bgn,
    $._b_sqt_str_bgn, // ' (start)
    $._r_sqt_str_ctn,
    $._br_sqt_str_ctn, // single quote scalar content
    $._r_sqt_str_end,
    $._br_sqt_str_end, // ' (end)

    // plain scalar (singleline in block/flow)
    $._r_sgl_pln_nul_blk,
    $._br_sgl_pln_nul_blk,
    $._b_sgl_pln_nul_blk,
    $._r_sgl_pln_nul_flw,
    $._br_sgl_pln_nul_flw,
    $._r_sgl_pln_bol_blk,
    $._br_sgl_pln_bol_blk,
    $._b_sgl_pln_bol_blk,
    $._r_sgl_pln_bol_flw,
    $._br_sgl_pln_bol_flw,
    $._r_sgl_pln_int_blk,
    $._br_sgl_pln_int_blk,
    $._b_sgl_pln_int_blk,
    $._r_sgl_pln_int_flw,
    $._br_sgl_pln_int_flw,
    $._r_sgl_pln_flt_blk,
    $._br_sgl_pln_flt_blk,
    $._b_sgl_pln_flt_blk,
    $._r_sgl_pln_flt_flw,
    $._br_sgl_pln_flt_flw,
    $._r_sgl_pln_str_blk,
    $._br_sgl_pln_str_blk,
    $._b_sgl_pln_str_blk,
    $._r_sgl_pln_str_flw,
    $._br_sgl_pln_str_flw,

    // plain scalar (multiline in block/flow)
    $._r_mtl_pln_str_blk,
    $._br_mtl_pln_str_blk,
    $._r_mtl_pln_str_flw,
    $._br_mtl_pln_str_flw,

    $._r_tag,
    $._br_tag,
    $._b_tag, // !tag
    $._r_acr_bgn,
    $._br_acr_bgn,
    $._b_acr_bgn,
    $._r_acr_ctn, // &id
    $._r_als_bgn,
    $._br_als_bgn,
    $._b_als_bgn,
    $._r_als_ctn, // *id

    $._bl,
    $.comment,
  ],

  extras: ($) => [$.comment],

  conflicts: ($) => [
    [$._r_prp, $._r_sgl_prp],
    [$._br_prp, $._br_sgl_prp],
    [$._flw_seq_tal, $._sgl_flw_seq_tal],
    [$._flw_map_tal, $._sgl_flw_map_tal],
    [$._flw_ann_par_tal, $._sgl_flw_ann_par_tal],
    [$._r_flw_seq_itm, $._r_sgl_flw_col_itm],
    [$._r_flw_map_itm, $._r_sgl_flw_col_itm],
    [$._r_flw_njl_ann_par, $._r_sgl_flw_njl_ann_par],
    [$._r_flw_exp_par, $._r_sgl_flw_exp_par],
    [$._r_dqt_str, $._r_sgl_dqt_str],
    [$._r_sqt_str, $._r_sgl_sqt_str],
    [$._r_pln_flw_val, $._r_sgl_pln_flw_val],

    /**
     * (_r_prp  _r_acr  •  _br_tag)
     *
     *    &str
     *    !!str a
     *
     * (_r_prp  _r_acr)  •  _br_tag
     *
     *    &map
     *    !!str a: 1
     */
    [$._r_prp],
    [$._br_prp],
  ],

  inline: ($) => [
    $._r_pln_blk,
    $._br_pln_blk,
    $._r_pln_flw,
    $._br_pln_flw,
    $._r_blk_seq_val,
    $._r_blk_map_val,
    $._r_flw_val_blk,
    $._br_flw_val_blk,
    $._r_sgl_flw_val_blk,
    $._br_sgl_flw_val_blk,
    $._b_sgl_flw_val_blk,
    $._r_flw_val_flw,
    $._br_flw_val_flw,
    $._r_sgl_flw_val_flw,
    $._r_flw_jsl_val,
    $._br_flw_jsl_val,
    $._r_sgl_flw_jsl_val,
    $._br_sgl_flw_jsl_val,
    $._b_sgl_flw_jsl_val,
    $._r_flw_njl_val_blk,
    $._br_flw_njl_val_blk,
    $._r_sgl_flw_njl_val_blk,
    $._br_sgl_flw_njl_val_blk,
    $._b_sgl_flw_njl_val_blk,
    $._r_flw_njl_val_flw,
    $._br_flw_njl_val_flw,
    $._r_sgl_flw_njl_val_flw,
  ],

  rules: {
    stream: ($) =>
      seq(
        optional(
          choice(
            seq(
              choice($._bgn_imp_doc, $._drs_doc, $._exp_doc),
              optional(choice($._doc_w_bgn_w_end_seq, $._doc_w_bgn_wo_end_seq))
            ),
            seq(
              choice(
                $._bgn_imp_doc_end,
                $._drs_doc_end,
                $._exp_doc_end,
                $._doc_end
              ),
              optional(
                choice(
                  $._doc_w_bgn_w_end_seq,
                  $._doc_w_bgn_wo_end_seq,
                  $._doc_wo_bgn_w_end_seq,
                  $._doc_wo_bgn_wo_end_seq
                )
              )
            )
          )
        ),
        $._eof
      ),

    _doc_w_bgn_w_end_seq: ($) =>
      seq(
        $._doc_w_bgn_w_end,
        optional(
          choice(
            $._doc_w_bgn_w_end_seq,
            $._doc_w_bgn_wo_end_seq,
            $._doc_wo_bgn_w_end_seq,
            $._doc_wo_bgn_wo_end_seq
          )
        )
      ),
    _doc_w_bgn_wo_end_seq: ($) =>
      seq(
        $._doc_w_bgn_wo_end,
        optional(choice($._doc_w_bgn_w_end_seq, $._doc_w_bgn_wo_end_seq))
      ),
    _doc_wo_bgn_w_end_seq: ($) =>
      seq(
        $._doc_wo_bgn_w_end,
        optional(
          choice(
            $._doc_w_bgn_w_end_seq,
            $._doc_w_bgn_wo_end_seq,
            $._doc_wo_bgn_w_end_seq,
            $._doc_wo_bgn_wo_end_seq
          )
        )
      ),
    _doc_wo_bgn_wo_end_seq: ($) =>
      seq(
        $._doc_wo_bgn_wo_end,
        optional(choice($._doc_w_bgn_w_end_seq, $._doc_w_bgn_wo_end_seq))
      ),

    _doc_w_bgn_w_end: ($) => choice($._exp_doc_end, $._doc_end),
    _doc_w_bgn_wo_end: ($) => $._exp_doc,
    _doc_wo_bgn_w_end: ($) => choice($._drs_doc_end, $._imp_doc_end),
    _doc_wo_bgn_wo_end: ($) => choice($._drs_doc, $._imp_doc),

    // document

    _bgn_imp_doc: ($) =>
      choice($._exp_doc_tal, $._r_blk_seq_r_val, $._r_blk_map_r_val),
    _drs_doc: ($) => seq(repeat1($._s_dir), $._exp_doc),
    _exp_doc: ($) => seq($._s_drs_end, optional($._exp_doc_tal)),
    _imp_doc: ($) =>
      choice(
        $._br_blk_seq_val,
        $._br_blk_map_val,
        $._br_blk_str_val,
        $._br_flw_val_blk
      ),

    _drs_doc_end: ($) => prec(1, seq($._drs_doc, $._s_doc_end)),
    _exp_doc_end: ($) => prec(1, seq($._exp_doc, $._s_doc_end)),
    _imp_doc_end: ($) => prec(1, seq($._imp_doc, $._s_doc_end)),
    _bgn_imp_doc_end: ($) => prec(1, seq($._bgn_imp_doc, $._s_doc_end)),
    _doc_end: ($) => $._s_doc_end,

    _exp_doc_tal: ($) =>
      choice(
        $._r_blk_seq_br_val,
        $._br_blk_seq_val,
        $._r_blk_map_br_val,
        $._br_blk_map_val,
        $._r_blk_str_val,
        $._br_blk_str_val,
        $._r_flw_val_blk,
        $._br_flw_val_blk
      ),

    // directive

    _s_dir: ($) => choice($._s_dir_yml, $._s_dir_tag, $._s_dir_rsv),

    _s_dir_yml: ($) => seq($._s_dir_yml_bgn, $._r_dir_yml_ver),
    _s_dir_tag: ($) =>
      seq($._s_dir_tag_bgn, $._r_dir_tag_hdl, $._r_dir_tag_pfx),
    _s_dir_rsv: ($) => seq($._s_dir_rsv_bgn, repeat($._r_dir_rsv_prm)),

    // property

    _r_prp_val: ($) => $._r_prp,
    _br_prp_val: ($) => $._br_prp,

    _r_sgl_prp_val: ($) => $._r_sgl_prp,
    _br_sgl_prp_val: ($) => $._br_sgl_prp,
    _b_sgl_prp_val: ($) => $._b_sgl_prp,

    _r_prp: ($) =>
      choice(
        seq($._r_acr, optional(choice($._r_tag, $._br_tag))),
        seq($._r_tag, optional(choice($._r_acr, $._br_acr)))
      ),
    _br_prp: ($) =>
      choice(
        seq($._br_acr, optional(choice($._r_tag, $._br_tag))),
        seq($._br_tag, optional(choice($._r_acr, $._br_acr)))
      ),

    _r_sgl_prp: ($) =>
      choice(
        seq($._r_acr, optional($._r_tag)),
        seq($._r_tag, optional($._r_acr))
      ),
    _br_sgl_prp: ($) =>
      choice(
        seq($._br_acr, optional($._r_tag)),
        seq($._br_tag, optional($._r_acr))
      ),
    _b_sgl_prp: ($) =>
      choice(
        seq($._b_acr, optional($._r_tag)),
        seq($._b_tag, optional($._r_acr))
      ),

    // block sequence

    _r_blk_seq_val: ($) => choice($._r_blk_seq_r_val, $._r_blk_seq_br_val),
    _r_blk_seq_r_val: ($) => $._r_blk_seq,
    _r_blk_seq_br_val: ($) => seq($._r_prp, $._br_blk_seq),
    _br_blk_seq_val: ($) =>
      choice($._br_blk_seq, seq($._br_prp, $._br_blk_seq)),

    _r_blk_seq_spc_val: ($) => seq($._r_prp, $._b_blk_seq_spc),
    _br_blk_seq_spc_val: ($) => seq($._br_prp, $._b_blk_seq_spc),
    _b_blk_seq_spc_val: ($) => $._b_blk_seq_spc,

    _r_blk_seq: ($) => seq($._r_blk_seq_itm, repeat($._b_blk_seq_itm), $._bl),
    _br_blk_seq: ($) => seq($._br_blk_seq_itm, repeat($._b_blk_seq_itm), $._bl),

    _b_blk_seq_spc: ($) => seq(repeat1($._b_blk_seq_itm), $._bl),

    _r_blk_seq_itm: ($) => seq($._r_blk_seq_bgn, optional($._blk_seq_itm_tal)),
    _br_blk_seq_itm: ($) =>
      seq($._br_blk_seq_bgn, optional($._blk_seq_itm_tal)),
    _b_blk_seq_itm: ($) => seq($._b_blk_seq_bgn, optional($._blk_seq_itm_tal)),

    _blk_seq_itm_tal: ($) =>
      choice(
        $._r_blk_seq_val,
        $._br_blk_seq_val,
        $._r_blk_map_val,
        $._br_blk_map_val,
        $._r_blk_str_val,
        $._br_blk_str_val,
        $._r_flw_val_blk,
        $._br_flw_val_blk
      ),

    // block mapping

    _r_blk_map_val: ($) => choice($._r_blk_map_r_val, $._r_blk_map_br_val),
    _r_blk_map_r_val: ($) => $._r_blk_map,
    _r_blk_map_br_val: ($) => seq($._r_prp, $._br_blk_map),
    _br_blk_map_val: ($) =>
      choice($._br_blk_map, seq($._br_prp, $._br_blk_map)),

    _r_blk_map: ($) => seq($._r_blk_map_itm, repeat($._b_blk_map_itm), $._bl),
    _br_blk_map: ($) => seq($._br_blk_map_itm, repeat($._b_blk_map_itm), $._bl),

    _r_blk_map_itm: ($) => choice($._r_blk_exp_itm, $._r_blk_imp_itm),
    _br_blk_map_itm: ($) => choice($._br_blk_exp_itm, $._br_blk_imp_itm),
    _b_blk_map_itm: ($) => choice($._b_blk_exp_itm, $._b_blk_imp_itm),

    _r_blk_exp_itm: ($) =>
      prec.right(
        choice(
          seq($._r_blk_key_itm, optional($._b_blk_val_itm)),
          $._r_blk_val_itm
        )
      ),
    _br_blk_exp_itm: ($) =>
      prec.right(
        choice(
          seq($._br_blk_key_itm, optional($._b_blk_val_itm)),
          $._br_blk_val_itm
        )
      ),
    _b_blk_exp_itm: ($) =>
      prec.right(
        choice(
          seq($._b_blk_key_itm, optional($._b_blk_val_itm)),
          $._b_blk_val_itm
        )
      ),

    _r_blk_key_itm: ($) =>
      seq($._r_blk_key_bgn, optional(field("key", $._blk_exp_itm_tal))),
    _br_blk_key_itm: ($) =>
      seq($._br_blk_key_bgn, optional(field("key", $._blk_exp_itm_tal))),
    _b_blk_key_itm: ($) =>
      seq($._b_blk_key_bgn, optional(field("key", $._blk_exp_itm_tal))),

    _r_blk_val_itm: ($) =>
      seq($._r_blk_val_bgn, optional(field("value", $._blk_exp_itm_tal))),
    _br_blk_val_itm: ($) =>
      seq($._br_blk_val_bgn, optional(field("value", $._blk_exp_itm_tal))),
    _b_blk_val_itm: ($) =>
      seq($._b_blk_val_bgn, optional(field("value", $._blk_exp_itm_tal))),

    _r_blk_imp_itm: ($) =>
      seq(field("key", $._r_sgl_flw_val_blk), $._blk_imp_itm_tal),
    _br_blk_imp_itm: ($) =>
      seq(field("key", $._br_sgl_flw_val_blk), $._blk_imp_itm_tal),
    _b_blk_imp_itm: ($) =>
      seq(field("key", $._b_sgl_flw_val_blk), $._blk_imp_itm_tal),

    _blk_exp_itm_tal: ($) =>
      choice(
        $._blk_seq_itm_tal,
        $._r_blk_seq_spc_val,
        $._br_blk_seq_spc_val,
        $._b_blk_seq_spc_val
      ),
    _blk_imp_itm_tal: ($) =>
      seq(
        $._r_blk_imp_bgn,
        optional(
          field(
            "value",
            choice(
              $._r_blk_seq_br_val,
              $._br_blk_seq_val,
              $._r_blk_seq_spc_val,
              $._br_blk_seq_spc_val,
              $._b_blk_seq_spc_val,
              $._r_blk_map_br_val,
              $._br_blk_map_val,
              $._r_blk_str_val,
              $._br_blk_str_val,
              $._r_flw_val_blk,
              $._br_flw_val_blk
            )
          )
        )
      ),

    // block scalar

    _r_blk_str_val: ($) =>
      choice($._r_blk_str, seq($._r_prp, choice($._r_blk_str, $._br_blk_str))),
    _br_blk_str_val: ($) =>
      choice(
        $._br_blk_str,
        seq($._br_prp, choice($._r_blk_str, $._br_blk_str))
      ),

    _r_blk_str: ($) =>
      seq(
        choice($._r_blk_lit_bgn, $._r_blk_fld_bgn),
        repeat($._br_blk_str_ctn),
        $._bl
      ),
    _br_blk_str: ($) =>
      seq(
        choice($._br_blk_lit_bgn, $._br_blk_fld_bgn),
        repeat($._br_blk_str_ctn),
        $._bl
      ),

    // flow value in block

    _r_flw_val_blk: ($) => choice($._r_flw_jsl_val, $._r_flw_njl_val_blk),
    _br_flw_val_blk: ($) => choice($._br_flw_jsl_val, $._br_flw_njl_val_blk),

    _r_sgl_flw_val_blk: ($) =>
      choice($._r_sgl_flw_jsl_val, $._r_sgl_flw_njl_val_blk),
    _br_sgl_flw_val_blk: ($) =>
      choice($._br_sgl_flw_jsl_val, $._br_sgl_flw_njl_val_blk),
    _b_sgl_flw_val_blk: ($) =>
      choice($._b_sgl_flw_jsl_val, $._b_sgl_flw_njl_val_blk),

    // flow value in flow

    _r_flw_val_flw: ($) => choice($._r_flw_jsl_val, $._r_flw_njl_val_flw),
    _br_flw_val_flw: ($) => choice($._br_flw_jsl_val, $._br_flw_njl_val_flw),

    _r_sgl_flw_val_flw: ($) =>
      choice($._r_sgl_flw_jsl_val, $._r_sgl_flw_njl_val_flw),

    // json-like flow value

    _r_flw_jsl_val: ($) =>
      choice(
        $._r_flw_seq_val,
        $._r_flw_map_val,
        $._r_dqt_str_val,
        $._r_sqt_str_val
      ),
    _br_flw_jsl_val: ($) =>
      choice(
        $._br_flw_seq_val,
        $._br_flw_map_val,
        $._br_dqt_str_val,
        $._br_sqt_str_val
      ),

    _r_sgl_flw_jsl_val: ($) =>
      choice(
        $._r_sgl_flw_seq_val,
        $._r_sgl_flw_map_val,
        $._r_sgl_dqt_str_val,
        $._r_sgl_sqt_str_val
      ),
    _br_sgl_flw_jsl_val: ($) =>
      choice(
        $._br_sgl_flw_seq_val,
        $._br_sgl_flw_map_val,
        $._br_sgl_dqt_str_val,
        $._br_sgl_sqt_str_val
      ),
    _b_sgl_flw_jsl_val: ($) =>
      choice(
        $._b_sgl_flw_seq_val,
        $._b_sgl_flw_map_val,
        $._b_sgl_dqt_str_val,
        $._b_sgl_sqt_str_val
      ),

    // non-json-like flow value in block

    _r_flw_njl_val_blk: ($) =>
      choice($._r_als_val, $._r_prp_val, $._r_pln_blk_val),
    _br_flw_njl_val_blk: ($) =>
      choice($._br_als_val, $._br_prp_val, $._br_pln_blk_val),

    _r_sgl_flw_njl_val_blk: ($) =>
      choice($._r_als_val, $._r_sgl_prp_val, $._r_sgl_pln_blk_val),
    _br_sgl_flw_njl_val_blk: ($) =>
      choice($._br_als_val, $._br_sgl_prp_val, $._br_sgl_pln_blk_val),
    _b_sgl_flw_njl_val_blk: ($) =>
      choice($._b_als_val, $._b_sgl_prp_val, $._b_sgl_pln_blk_val),

    // non-json-like flow value in flow

    _r_flw_njl_val_flw: ($) =>
      choice($._r_als_val, $._r_prp_val, $._r_pln_flw_val),
    _br_flw_njl_val_flw: ($) =>
      choice($._br_als_val, $._br_prp_val, $._br_pln_flw_val),

    _r_sgl_flw_njl_val_flw: ($) =>
      choice($._r_als_val, $._r_sgl_prp_val, $._r_sgl_pln_flw_val),

    // flow sequence

    _r_flw_seq_val: ($) =>
      choice($._r_flw_seq, seq($._r_prp, choice($._r_flw_seq, $._br_flw_seq))),
    _br_flw_seq_val: ($) =>
      choice(
        $._br_flw_seq,
        seq($._br_prp, choice($._r_flw_seq, $._br_flw_seq))
      ),

    _r_sgl_flw_seq_val: ($) =>
      choice($._r_sgl_flw_seq, seq($._r_sgl_prp, $._r_sgl_flw_seq)),
    _br_sgl_flw_seq_val: ($) =>
      choice($._br_sgl_flw_seq, seq($._br_sgl_prp, $._r_sgl_flw_seq)),
    _b_sgl_flw_seq_val: ($) =>
      choice($._b_sgl_flw_seq, seq($._b_sgl_prp, $._r_sgl_flw_seq)),

    _r_flw_seq: ($) => seq($._r_flw_seq_bgn, $._flw_seq_tal),
    _br_flw_seq: ($) => seq($._br_flw_seq_bgn, $._flw_seq_tal),

    _r_sgl_flw_seq: ($) => seq($._r_flw_seq_bgn, $._sgl_flw_seq_tal),
    _br_sgl_flw_seq: ($) => seq($._br_flw_seq_bgn, $._sgl_flw_seq_tal),
    _b_sgl_flw_seq: ($) => seq($._b_flw_seq_bgn, $._sgl_flw_seq_tal),

    _flw_seq_tal: ($) =>
      seq(
        optional(choice($._r_flw_seq_dat, $._br_flw_seq_dat)),
        choice($._r_flw_seq_end, $._br_flw_seq_end)
      ),
    _sgl_flw_seq_tal: ($) =>
      seq(optional($._r_sgl_flw_col_dat), $._r_flw_seq_end),

    // flow mapping

    _r_flw_map_val: ($) =>
      choice($._r_flw_map, seq($._r_prp, choice($._r_flw_map, $._br_flw_map))),
    _br_flw_map_val: ($) =>
      choice(
        $._br_flw_map,
        seq($._br_prp, choice($._r_flw_map, $._br_flw_map))
      ),

    _r_sgl_flw_map_val: ($) =>
      choice($._r_sgl_flw_map, seq($._r_sgl_prp, $._r_sgl_flw_map)),
    _br_sgl_flw_map_val: ($) =>
      choice($._br_sgl_flw_map, seq($._br_sgl_prp, $._r_sgl_flw_map)),
    _b_sgl_flw_map_val: ($) =>
      choice($._b_sgl_flw_map, seq($._b_sgl_prp, $._r_sgl_flw_map)),

    _r_flw_map: ($) => seq($._r_flw_map_bgn, $._flw_map_tal),
    _br_flw_map: ($) => seq($._br_flw_map_bgn, $._flw_map_tal),

    _r_sgl_flw_map: ($) => seq($._r_flw_map_bgn, $._sgl_flw_map_tal),
    _br_sgl_flw_map: ($) => seq($._br_flw_map_bgn, $._sgl_flw_map_tal),
    _b_sgl_flw_map: ($) => seq($._b_flw_map_bgn, $._sgl_flw_map_tal),

    _flw_map_tal: ($) =>
      seq(
        optional(choice($._r_flw_map_dat, $._br_flw_map_dat)),
        choice($._r_flw_map_end, $._br_flw_map_end)
      ),
    _sgl_flw_map_tal: ($) =>
      seq(optional($._r_sgl_flw_col_dat), $._r_flw_map_end),

    // flow collection data

    _r_flw_seq_dat: ($) =>
      seq(
        $._r_flw_seq_itm,
        repeat($._flw_seq_dat_rpt),
        optional(choice($._r_flw_sep_bgn, $._br_flw_sep_bgn))
      ),
    _br_flw_seq_dat: ($) =>
      seq(
        $._br_flw_seq_itm,
        repeat($._flw_seq_dat_rpt),
        optional(choice($._r_flw_sep_bgn, $._br_flw_sep_bgn))
      ),

    _r_flw_map_dat: ($) =>
      seq(
        $._r_flw_map_itm,
        repeat($._flw_map_dat_rpt),
        optional(choice($._r_flw_sep_bgn, $._br_flw_sep_bgn))
      ),
    _br_flw_map_dat: ($) =>
      seq(
        $._br_flw_map_itm,
        repeat($._flw_map_dat_rpt),
        optional(choice($._r_flw_sep_bgn, $._br_flw_sep_bgn))
      ),

    _r_sgl_flw_col_dat: ($) =>
      seq(
        $._r_sgl_flw_col_itm,
        repeat($._sgl_flw_col_dat_rpt),
        optional($._r_flw_sep_bgn)
      ),

    _flw_seq_dat_rpt: ($) =>
      seq(
        choice($._r_flw_sep_bgn, $._br_flw_sep_bgn),
        choice($._r_flw_seq_itm, $._br_flw_seq_itm)
      ),
    _flw_map_dat_rpt: ($) =>
      seq(
        choice($._r_flw_sep_bgn, $._br_flw_sep_bgn),
        choice($._r_flw_map_itm, $._br_flw_map_itm)
      ),

    _sgl_flw_col_dat_rpt: ($) => seq($._r_flw_sep_bgn, $._r_sgl_flw_col_itm),

    // flow collection item

    _r_flw_seq_itm: ($) =>
      choice(
        $._r_flw_val_flw,
        $._r_flw_exp_par,
        $._r_flw_imp_r_par,
        $._r_flw_njl_ann_par
      ),
    _br_flw_seq_itm: ($) =>
      choice(
        $._br_flw_val_flw,
        $._br_flw_exp_par,
        $._br_flw_imp_r_par,
        $._br_flw_njl_ann_par
      ),

    _r_flw_map_itm: ($) =>
      choice(
        $._r_flw_val_flw,
        $._r_flw_exp_par,
        $._r_flw_imp_r_par,
        $._r_flw_imp_br_par,
        $._r_flw_njl_ann_par
      ),
    _br_flw_map_itm: ($) =>
      choice(
        $._br_flw_val_flw,
        $._br_flw_exp_par,
        $._br_flw_imp_r_par,
        $._br_flw_imp_br_par,
        $._br_flw_njl_ann_par
      ),

    _r_sgl_flw_col_itm: ($) =>
      choice(
        $._r_sgl_flw_val_flw,
        $._r_sgl_flw_exp_par,
        $._r_sgl_flw_imp_par,
        $._r_sgl_flw_njl_ann_par
      ),

    // explicit flow pair

    _r_flw_exp_par: ($) =>
      seq(
        $._r_flw_key_bgn,
        optional(
          choice(
            $._r_flw_imp_r_par,
            $._r_flw_imp_br_par,
            $._br_flw_imp_r_par,
            $._br_flw_imp_br_par
          )
        )
      ),
    _br_flw_exp_par: ($) =>
      seq(
        $._br_flw_key_bgn,
        optional(
          choice(
            $._r_flw_imp_r_par,
            $._r_flw_imp_br_par,
            $._br_flw_imp_r_par,
            $._br_flw_imp_br_par
          )
        )
      ),

    _r_sgl_flw_exp_par: ($) =>
      seq($._r_flw_key_bgn, optional($._r_sgl_flw_imp_par)),

    // implicit flow pair

    _r_flw_imp_r_par: ($) =>
      choice(
        seq(field("key", $._r_flw_jsl_val), $._r_flw_jsl_ann_par),
        seq(field("key", $._r_flw_njl_val_flw), $._r_flw_njl_ann_par)
      ),
    _r_flw_imp_br_par: ($) =>
      choice(
        seq(field("key", $._r_flw_jsl_val), $._br_flw_jsl_ann_par),
        seq(field("key", $._r_flw_njl_val_flw), $._br_flw_njl_ann_par)
      ),
    _br_flw_imp_r_par: ($) =>
      choice(
        seq(field("key", $._br_flw_jsl_val), $._r_flw_jsl_ann_par),
        seq(field("key", $._br_flw_njl_val_flw), $._r_flw_njl_ann_par)
      ),
    _br_flw_imp_br_par: ($) =>
      choice(
        seq(field("key", $._br_flw_jsl_val), $._br_flw_jsl_ann_par),
        seq(field("key", $._br_flw_njl_val_flw), $._br_flw_njl_ann_par)
      ),

    _r_sgl_flw_imp_par: ($) =>
      choice(
        seq(field("key", $._r_sgl_flw_jsl_val), $._r_sgl_flw_jsl_ann_par),
        seq(field("key", $._r_sgl_flw_njl_val_flw), $._r_sgl_flw_njl_ann_par)
      ),

    // anonymous flow pair

    _r_flw_jsl_ann_par: ($) =>
      seq($._r_flw_jsv_bgn, optional(field("value", $._flw_ann_par_tal))),
    _br_flw_jsl_ann_par: ($) =>
      seq($._br_flw_jsv_bgn, optional(field("value", $._flw_ann_par_tal))),

    _r_sgl_flw_jsl_ann_par: ($) =>
      seq($._r_flw_jsv_bgn, optional(field("value", $._sgl_flw_ann_par_tal))),

    _r_flw_njl_ann_par: ($) =>
      seq($._r_flw_njv_bgn, optional(field("value", $._flw_ann_par_tal))),
    _br_flw_njl_ann_par: ($) =>
      seq($._br_flw_njv_bgn, optional(field("value", $._flw_ann_par_tal))),

    _r_sgl_flw_njl_ann_par: ($) =>
      seq($._r_flw_njv_bgn, optional(field("value", $._sgl_flw_ann_par_tal))),

    _flw_ann_par_tal: ($) => choice($._r_flw_val_flw, $._br_flw_val_flw),
    _sgl_flw_ann_par_tal: ($) => $._r_sgl_flw_val_flw,

    // double quote scalar

    _r_dqt_str_val: ($) =>
      choice($._r_dqt_str, seq($._r_prp, choice($._r_dqt_str, $._br_dqt_str))),
    _br_dqt_str_val: ($) =>
      choice(
        $._br_dqt_str,
        seq($._br_prp, choice($._r_dqt_str, $._br_dqt_str))
      ),

    _r_sgl_dqt_str_val: ($) =>
      choice($._r_sgl_dqt_str, seq($._r_sgl_prp, $._r_sgl_dqt_str)),
    _br_sgl_dqt_str_val: ($) =>
      choice($._br_sgl_dqt_str, seq($._br_sgl_prp, $._r_sgl_dqt_str)),
    _b_sgl_dqt_str_val: ($) =>
      choice($._b_sgl_dqt_str, seq($._b_sgl_prp, $._r_sgl_dqt_str)),

    _r_dqt_str: ($) =>
      seq(
        $._r_dqt_str_bgn,
        optional($._r_sgl_dqt_ctn),
        repeat($._br_mtl_dqt_ctn),
        choice($._r_dqt_str_end, $._br_dqt_str_end)
      ),
    _br_dqt_str: ($) =>
      seq(
        $._br_dqt_str_bgn,
        optional($._r_sgl_dqt_ctn),
        repeat($._br_mtl_dqt_ctn),
        choice($._r_dqt_str_end, $._br_dqt_str_end)
      ),

    _r_sgl_dqt_str: ($) =>
      seq($._r_dqt_str_bgn, optional($._r_sgl_dqt_ctn), $._r_dqt_str_end),
    _br_sgl_dqt_str: ($) =>
      seq($._br_dqt_str_bgn, optional($._r_sgl_dqt_ctn), $._r_dqt_str_end),
    _b_sgl_dqt_str: ($) =>
      seq($._b_dqt_str_bgn, optional($._r_sgl_dqt_ctn), $._r_dqt_str_end),

    _r_sgl_dqt_ctn: ($) => repeat1($._r_dqt_str_ctn),
    _br_mtl_dqt_ctn: ($) => seq($._br_dqt_str_ctn, repeat($._r_dqt_str_ctn)),

    // single quote scalar

    _r_sqt_str_val: ($) =>
      choice($._r_sqt_str, seq($._r_prp, choice($._r_sqt_str, $._br_sqt_str))),
    _br_sqt_str_val: ($) =>
      choice(
        $._br_sqt_str,
        seq($._br_prp, choice($._r_sqt_str, $._br_sqt_str))
      ),

    _r_sgl_sqt_str_val: ($) =>
      choice($._r_sgl_sqt_str, seq($._r_sgl_prp, $._r_sgl_sqt_str)),
    _br_sgl_sqt_str_val: ($) =>
      choice($._br_sgl_sqt_str, seq($._br_sgl_prp, $._r_sgl_sqt_str)),
    _b_sgl_sqt_str_val: ($) =>
      choice($._b_sgl_sqt_str, seq($._b_sgl_prp, $._r_sgl_sqt_str)),

    _r_sqt_str: ($) =>
      seq(
        $._r_sqt_str_bgn,
        optional($._r_sgl_sqt_ctn),
        repeat($._br_mtl_sqt_ctn),
        choice($._r_sqt_str_end, $._br_sqt_str_end)
      ),
    _br_sqt_str: ($) =>
      seq(
        $._br_sqt_str_bgn,
        optional($._r_sgl_sqt_ctn),
        repeat($._br_mtl_sqt_ctn),
        choice($._r_sqt_str_end, $._br_sqt_str_end)
      ),

    _r_sgl_sqt_str: ($) =>
      seq($._r_sqt_str_bgn, optional($._r_sgl_sqt_ctn), $._r_sqt_str_end),
    _br_sgl_sqt_str: ($) =>
      seq($._br_sqt_str_bgn, optional($._r_sgl_sqt_ctn), $._r_sqt_str_end),
    _b_sgl_sqt_str: ($) =>
      seq($._b_sqt_str_bgn, optional($._r_sgl_sqt_ctn), $._r_sqt_str_end),

    _r_sgl_sqt_ctn: ($) => repeat1($._r_sqt_str_ctn),
    _br_mtl_sqt_ctn: ($) => seq($._br_sqt_str_ctn, repeat($._r_sqt_str_ctn)),

    // plain scalar in block

    _r_pln_blk_val: ($) =>
      choice($._r_pln_blk, seq($._r_prp, choice($._r_pln_blk, $._br_pln_blk))),
    _br_pln_blk_val: ($) =>
      choice(
        $._br_pln_blk,
        seq($._br_prp, choice($._r_pln_blk, $._br_pln_blk))
      ),

    _r_sgl_pln_blk_val: ($) =>
      choice($._r_sgl_pln_blk, seq($._r_sgl_prp, $._r_sgl_pln_blk)),
    _br_sgl_pln_blk_val: ($) =>
      choice($._br_sgl_pln_blk, seq($._br_sgl_prp, $._r_sgl_pln_blk)),
    _b_sgl_pln_blk_val: ($) =>
      choice($._b_sgl_pln_blk, seq($._b_sgl_prp, $._r_sgl_pln_blk)),

    _r_pln_blk: ($) => choice($._r_sgl_pln_blk, $._r_mtl_pln_blk),
    _br_pln_blk: ($) => choice($._br_sgl_pln_blk, $._br_mtl_pln_blk),

    // plain scalar in flow

    _r_pln_flw_val: ($) =>
      choice($._r_pln_flw, seq($._r_prp, choice($._r_pln_flw, $._br_pln_flw))),
    _br_pln_flw_val: ($) =>
      choice(
        $._br_pln_flw,
        seq($._br_prp, choice($._r_pln_flw, $._br_pln_flw))
      ),

    _r_sgl_pln_flw_val: ($) =>
      choice($._r_sgl_pln_flw, seq($._r_sgl_prp, $._r_sgl_pln_flw)),

    _r_pln_flw: ($) => choice($._r_sgl_pln_flw, $._r_mtl_pln_flw),
    _br_pln_flw: ($) => choice($._br_sgl_pln_flw, $._br_mtl_pln_flw),

    // plain scalar schema

    _r_sgl_pln_blk: ($) =>
      choice(
        $._r_sgl_pln_nul_blk,
        $._r_sgl_pln_bol_blk,
        $._r_sgl_pln_int_blk,
        $._r_sgl_pln_flt_blk,
        $._r_sgl_pln_str_blk
      ),
    _br_sgl_pln_blk: ($) =>
      choice(
        $._br_sgl_pln_nul_blk,
        $._br_sgl_pln_bol_blk,
        $._br_sgl_pln_int_blk,
        $._br_sgl_pln_flt_blk,
        $._br_sgl_pln_str_blk
      ),
    _b_sgl_pln_blk: ($) =>
      choice(
        $._b_sgl_pln_nul_blk,
        $._b_sgl_pln_bol_blk,
        $._b_sgl_pln_int_blk,
        $._b_sgl_pln_flt_blk,
        $._b_sgl_pln_str_blk
      ),
    _r_sgl_pln_flw: ($) =>
      choice(
        $._r_sgl_pln_nul_flw,
        $._r_sgl_pln_bol_flw,
        $._r_sgl_pln_int_flw,
        $._r_sgl_pln_flt_flw,
        $._r_sgl_pln_str_flw
      ),
    _br_sgl_pln_flw: ($) =>
      choice(
        $._br_sgl_pln_nul_flw,
        $._br_sgl_pln_bol_flw,
        $._br_sgl_pln_int_flw,
        $._br_sgl_pln_flt_flw,
        $._br_sgl_pln_str_flw
      ),

    _r_mtl_pln_blk: ($) => $._r_mtl_pln_str_blk,
    _br_mtl_pln_blk: ($) => $._br_mtl_pln_str_blk,
    _r_mtl_pln_flw: ($) => $._r_mtl_pln_str_flw,
    _br_mtl_pln_flw: ($) => $._br_mtl_pln_str_flw,

    // alias

    _r_als_val: ($) => $._r_als,
    _br_als_val: ($) => $._br_als,
    _b_als_val: ($) => $._b_als,

    _r_als: ($) => seq($._r_als_bgn, $._r_als_ctn),
    _br_als: ($) => seq($._br_als_bgn, $._r_als_ctn),
    _b_als: ($) => seq($._b_als_bgn, $._r_als_ctn),

    // anchor

    _r_acr: ($) => seq($._r_acr_bgn, $._r_acr_ctn),
    _br_acr: ($) => seq($._br_acr_bgn, $._r_acr_ctn),
    _b_acr: ($) => seq($._b_acr_bgn, $._r_acr_ctn),
  },
});

module.exports = global_alias(
  global_alias(module.exports, {
    ..._("yaml_directive", "_s_dir_yml"),
    ..._("yaml_version", "_r_dir_yml_ver"),
    ..._("tag_directive", "_s_dir_tag"),
    ..._("tag_handle", "_r_dir_tag_hdl"),
    ..._("tag_prefix", "_r_dir_tag_pfx"),
    ..._("reserved_directive", "_s_dir_rsv"),
    ..._("directive_name", "_s_dir_rsv_bgn"),
    ..._("directive_parameter", "_r_dir_rsv_prm"),
    ..._(
      "flow_node",
      "_r_prp_val",
      "_br_prp_val",
      "_r_sgl_prp_val",
      "_br_sgl_prp_val",
      "_b_sgl_prp_val"
    ),
    ..._("tag", "_r_tag", "_br_tag", "_b_tag"),
    ..._("anchor", "_r_acr", "_br_acr", "_b_acr"),
    ..._("anchor_name", "_r_acr_ctn"),
    ..._("flow_node", "_r_als_val", "_br_als_val", "_b_als_val"),
    ..._("alias", "_r_als", "_br_als", "_b_als"),
    ..._("alias_name", "_r_als_ctn"),
    ..._("document", "_bgn_imp_doc", "_imp_doc"),
    ..._(
      ["document"],
      "_drs_doc",
      "_exp_doc",
      "_doc_end",
      "_bgn_imp_doc_end",
      "_drs_doc_end",
      "_exp_doc_end",
      "_imp_doc_end"
    ),
    ..._(
      "block_node",
      "_r_blk_seq_r_val",
      "_r_blk_seq_br_val",
      "_br_blk_seq_val",
      "_r_blk_seq_spc_val",
      "_br_blk_seq_spc_val",
      "_b_blk_seq_spc_val"
    ),
    ..._(
      "block_node",
      "_r_blk_map_r_val",
      "_r_blk_map_br_val",
      "_br_blk_map_val"
    ),
    ..._("block_node", "_r_blk_str_val", "_br_blk_str_val"),
    ..._("block_sequence", "_r_blk_seq", "_br_blk_seq", "_b_blk_seq_spc"),
    ..._("block_mapping", "_r_blk_map", "_br_blk_map"),
    ..._("block_scalar", "_r_blk_str", "_br_blk_str"),
    ..._(
      "block_sequence_item",
      "_r_blk_seq_itm",
      "_br_blk_seq_itm",
      "_b_blk_seq_itm"
    ),
    ..._(
      "block_mapping_pair",
      "_r_blk_exp_itm",
      "_br_blk_exp_itm",
      "_b_blk_exp_itm"
    ),
    ..._(
      "block_mapping_pair",
      "_r_blk_imp_itm",
      "_br_blk_imp_itm",
      "_b_blk_imp_itm"
    ),
    ..._(
      "flow_node",
      "_r_flw_seq_val",
      "_br_flw_seq_val",
      "_r_sgl_flw_seq_val",
      "_br_sgl_flw_seq_val",
      "_b_sgl_flw_seq_val"
    ),
    ..._(
      "flow_node",
      "_r_flw_map_val",
      "_br_flw_map_val",
      "_r_sgl_flw_map_val",
      "_br_sgl_flw_map_val",
      "_b_sgl_flw_map_val"
    ),
    ..._(
      "flow_sequence",
      "_r_flw_seq",
      "_br_flw_seq",
      "_r_sgl_flw_seq",
      "_br_sgl_flw_seq",
      "_b_sgl_flw_seq"
    ),
    ..._(
      "flow_mapping",
      "_r_flw_map",
      "_br_flw_map",
      "_r_sgl_flw_map",
      "_br_sgl_flw_map",
      "_b_sgl_flw_map"
    ),
    ..._(
      ["flow_pair"],
      "_r_flw_exp_par",
      "_br_flw_exp_par",
      "_r_sgl_flw_exp_par",
      "_r_flw_imp_r_par",
      "_r_flw_imp_br_par",
      "_br_flw_imp_r_par",
      "_br_flw_imp_br_par",
      "_r_sgl_flw_imp_par",
      "_r_flw_njl_ann_par",
      "_br_flw_njl_ann_par",
      "_r_sgl_flw_njl_ann_par"
    ),
    ..._(
      "flow_node",
      "_r_dqt_str_val",
      "_br_dqt_str_val",
      "_r_sgl_dqt_str_val",
      "_br_sgl_dqt_str_val",
      "_b_sgl_dqt_str_val"
    ),
    ..._(
      "flow_node",
      "_r_sqt_str_val",
      "_br_sqt_str_val",
      "_r_sgl_sqt_str_val",
      "_br_sgl_sqt_str_val",
      "_b_sgl_sqt_str_val"
    ),
    ..._(
      "flow_node",
      "_r_pln_blk_val",
      "_br_pln_blk_val",
      "_r_sgl_pln_blk_val",
      "_br_sgl_pln_blk_val",
      "_b_sgl_pln_blk_val",
      "_r_pln_flw_val",
      "_br_pln_flw_val",
      "_r_sgl_pln_flw_val"
    ),
    ..._(
      "double_quote_scalar",
      "_r_dqt_str",
      "_br_dqt_str",
      "_r_sgl_dqt_str",
      "_br_sgl_dqt_str",
      "_b_sgl_dqt_str"
    ),
    ..._(
      "single_quote_scalar",
      "_r_sqt_str",
      "_br_sqt_str",
      "_r_sgl_sqt_str",
      "_br_sgl_sqt_str",
      "_b_sgl_sqt_str"
    ),
    ..._(
      "plain_scalar",
      "_r_mtl_pln_blk",
      "_br_mtl_pln_blk",
      "_r_sgl_pln_blk",
      "_br_sgl_pln_blk",
      "_b_sgl_pln_blk",
      "_r_mtl_pln_flw",
      "_br_mtl_pln_flw",
      "_r_sgl_pln_flw",
      "_br_sgl_pln_flw"
    ),
    ..._(
      "quote_content",
      "_br_dqt_str_ctn",
      "_r_dqt_str_ctn",
      "_br_sqt_str_ctn",
      "_r_sqt_str_ctn"
    ),
    ..._(
      "null_scalar",
      "_r_sgl_pln_nul_blk",
      "_br_sgl_pln_nul_blk",
      "_b_sgl_pln_nul_blk",
      "_r_sgl_pln_nul_flw",
      "_br_sgl_pln_nul_flw"
    ),
    ..._(
      "boolean_scalar",
      "_r_sgl_pln_bol_blk",
      "_br_sgl_pln_bol_blk",
      "_b_sgl_pln_bol_blk",
      "_r_sgl_pln_bol_flw",
      "_br_sgl_pln_bol_flw"
    ),
    ..._(
      "integer_scalar",
      "_r_sgl_pln_int_blk",
      "_br_sgl_pln_int_blk",
      "_b_sgl_pln_int_blk",
      "_r_sgl_pln_int_flw",
      "_br_sgl_pln_int_flw"
    ),
    ..._(
      "float_scalar",
      "_r_sgl_pln_flt_blk",
      "_br_sgl_pln_flt_blk",
      "_b_sgl_pln_flt_blk",
      "_r_sgl_pln_flt_flw",
      "_br_sgl_pln_flt_flw"
    ),
    ..._(
      "string_scalar",
      "_r_sgl_pln_str_blk",
      "_br_sgl_pln_str_blk",
      "_b_sgl_pln_str_blk",
      "_r_sgl_pln_str_flw",
      "_br_sgl_pln_str_flw",
      "_r_mtl_pln_str_blk",
      "_br_mtl_pln_str_blk",
      "_r_mtl_pln_str_flw",
      "_br_mtl_pln_str_flw"
    ),
  }),
  {
    ..._("---", "_s_drs_end"),
    ..._("...", "_s_doc_end"),
    ..._("-", "_r_blk_seq_bgn", "_br_blk_seq_bgn", "_b_blk_seq_bgn"),
    ..._("?", "_r_blk_key_bgn", "_br_blk_key_bgn", "_b_blk_key_bgn"),
    ..._(":", "_r_blk_val_bgn", "_br_blk_val_bgn", "_b_blk_val_bgn"),
    ..._(":", "_r_blk_imp_bgn"),
    ..._("|", "_r_blk_lit_bgn", "_br_blk_lit_bgn"),
    ..._(">", "_r_blk_fld_bgn", "_br_blk_fld_bgn"),
    ..._("[", "_r_flw_seq_bgn", "_br_flw_seq_bgn", "_b_flw_seq_bgn"),
    ..._("]", "_r_flw_seq_end", "_br_flw_seq_end"),
    ..._("{", "_r_flw_map_bgn", "_br_flw_map_bgn", "_b_flw_map_bgn"),
    ..._("}", "_r_flw_map_end", "_br_flw_map_end"),
    ..._(",", "_r_flw_sep_bgn", "_br_flw_sep_bgn"),
    ..._("?", "_r_flw_key_bgn", "_br_flw_key_bgn"),
    ..._(":", "_r_flw_jsv_bgn", "_br_flw_jsv_bgn"),
    ..._(":", "_r_flw_njv_bgn", "_br_flw_njv_bgn"),
    ..._('"', "_r_dqt_str_bgn", "_br_dqt_str_bgn", "_b_dqt_str_bgn"),
    ..._('"', "_r_dqt_str_end", "_br_dqt_str_end"),
    ..._("'", "_r_sqt_str_bgn", "_br_sqt_str_bgn", "_b_sqt_str_bgn"),
    ..._("'", "_r_sqt_str_end", "_br_sqt_str_end"),
    ..._("*", "_r_als_bgn", "_br_als_bgn", "_b_als_bgn"),
    ..._("&", "_r_acr_bgn", "_br_acr_bgn", "_b_acr_bgn"),
  }
);

function _(alias_value, ...rule_names) {
  const alias_content = {};
  if (typeof alias_value === "string") {
    alias_content.name = alias_value;
  } else if (Array.isArray(alias_value)) {
    alias_content.name = alias_value[0];
    alias_content.shallow = true;
  } else {
    throw new Error(`Unexpected value ${JSON.stringify(alias_value)}`);
  }
  const alias_map = {};
  for (const rule_name of rule_names) {
    alias_map[rule_name] = alias_content;
  }
  return alias_map;
}

function global_alias(grammar_json, alias_map) {
  const new_rules = {};
  const new_grammar = { ...grammar_json, rules: new_rules };
  const checklist = Object.fromEntries(
    Object.entries(alias_map).map(([k, v]) => [k, 0])
  );
  for (const [rule_name, rule] of Object.entries(grammar_json.rules)) {
    new_rules[rule_name] =
      rule_name in alias_map && alias_map[rule_name].shallow
        ? rule
        : recursive_alias(rule, alias_map, checklist);
  }
  for (const [rule_name, counter] of Object.entries(checklist)) {
    if (counter === 0) {
      console.warn(
        `warning: global_alias for ${JSON.stringify(rule_name)} is not used.`
      );
    }
  }
  return new_grammar;
}

function recursive_alias(rule, alias_map, checklist) {
  switch (rule.type) {
    case "CHOICE":
    case "SEQ":
      return {
        ...rule,
        members: rule.members.map((member) =>
          recursive_alias(member, alias_map, checklist)
        ),
      };
    case "REPEAT":
    case "REPEAT1":
    case "FIELD":
    case "PREC":
    case "PREC_RIGHT":
      return {
        ...rule,
        content: recursive_alias(rule.content, alias_map, checklist),
      };
    case "SYMBOL":
      if (rule.name in alias_map) {
        checklist[rule.name]++;
        const alias = alias_map[rule.name].name;
        return {
          type: "ALIAS",
          content: rule,
          named: /[a-z]/i.test(alias),
          value: alias,
        };
      }
    case "BLANK":
    case "ALIAS":
      return rule;
    default:
      throw new Error(`Unexpected rule type ${JSON.stringify(rule.type)}`);
  }
}