package com.semmle.jcorn;

import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import java.util.regex.Pattern;

/// identifier.js
public class Identifiers {
  public static enum Dialect {
    ECMA_3,
    ECMA_5,
    ECMA_6,
    ECMA_7,
    ECMA_8,
    STRICT,
    STRICT_BIND
  }

  // Reserved word lists for various dialects of the language
  public static final Map<Dialect, Set<String>> reservedWords = new LinkedHashMap<>();

  static {
    reservedWords.put(
        Dialect.ECMA_3,
        stringSet(
            "abstract boolean byte char class double enum export extends final float goto implements import int interface long native package private protected public short static super synchronized throws transient volatile"));
    reservedWords.put(Dialect.ECMA_5, stringSet("class enum extends super const export import"));
    reservedWords.put(Dialect.ECMA_6, stringSet("enum"));
    reservedWords.put(Dialect.ECMA_7, stringSet("enum"));
    reservedWords.put(Dialect.ECMA_8, stringSet("enum"));
    reservedWords.put(
        Dialect.STRICT,
        stringSet("implements interface let package private protected public static yield"));
    reservedWords.put(Dialect.STRICT_BIND, stringSet("eval arguments"));
  }

  // And the keywords
  private static final String ecma5AndLessKeywords =
      "break case catch continue debugger default do else finally for function if return switch throw try var while with null true false instanceof typeof void delete new in this";
  private static final String ecma6Keywords =
      ecma5AndLessKeywords + " const class extends export import super";

  public static final Map<Dialect, Set<String>> keywords = new LinkedHashMap<>();

  static {
    keywords.put(Dialect.ECMA_5, stringSet(ecma5AndLessKeywords));
    keywords.put(Dialect.ECMA_6, stringSet(ecma6Keywords));
  }

  private static Set<String> stringSet(String words) {
    Set<String> result = new LinkedHashSet<String>();
    for (String word : words.split(" ")) result.add(word);
    return result;
  }

  // ## Character categories

  private static final String nonASCIIidentifierStartChars =
      "\\xaa\\xb5\\xba\\xc0-\\xd6\\xd8-\\xf6\\xf8-\\u02c1\\u02c6-\\u02d1\\u02e0-\\u02e4\\u02ec\\u02ee\\u0370-\\u0374\\u0376\\u0377\\u037a-\\u037d\\u037f\\u0386\\u0388-\\u038a\\u038c\\u038e-\\u03a1\\u03a3-\\u03f5\\u03f7-\\u0481\\u048a-\\u052f\\u0531-\\u0556\\u0559\\u0561-\\u0587\\u05d0-\\u05ea\\u05f0-\\u05f2\\u0620-\\u064a\\u066e\\u066f\\u0671-\\u06d3\\u06d5\\u06e5\\u06e6\\u06ee\\u06ef\\u06fa-\\u06fc\\u06ff\\u0710\\u0712-\\u072f\\u074d-\\u07a5\\u07b1\\u07ca-\\u07ea\\u07f4\\u07f5\\u07fa\\u0800-\\u0815\\u081a\\u0824\\u0828\\u0840-\\u0858\\u08a0-\\u08b4\\u08b6-\\u08bd\\u0904-\\u0939\\u093d\\u0950\\u0958-\\u0961\\u0971-\\u0980\\u0985-\\u098c\\u098f\\u0990\\u0993-\\u09a8\\u09aa-\\u09b0\\u09b2\\u09b6-\\u09b9\\u09bd\\u09ce\\u09dc\\u09dd\\u09df-\\u09e1\\u09f0\\u09f1\\u0a05-\\u0a0a\\u0a0f\\u0a10\\u0a13-\\u0a28\\u0a2a-\\u0a30\\u0a32\\u0a33\\u0a35\\u0a36\\u0a38\\u0a39\\u0a59-\\u0a5c\\u0a5e\\u0a72-\\u0a74\\u0a85-\\u0a8d\\u0a8f-\\u0a91\\u0a93-\\u0aa8\\u0aaa-\\u0ab0\\u0ab2\\u0ab3\\u0ab5-\\u0ab9\\u0abd\\u0ad0\\u0ae0\\u0ae1\\u0af9\\u0b05-\\u0b0c\\u0b0f\\u0b10\\u0b13-\\u0b28\\u0b2a-\\u0b30\\u0b32\\u0b33\\u0b35-\\u0b39\\u0b3d\\u0b5c\\u0b5d\\u0b5f-\\u0b61\\u0b71\\u0b83\\u0b85-\\u0b8a\\u0b8e-\\u0b90\\u0b92-\\u0b95\\u0b99\\u0b9a\\u0b9c\\u0b9e\\u0b9f\\u0ba3\\u0ba4\\u0ba8-\\u0baa\\u0bae-\\u0bb9\\u0bd0\\u0c05-\\u0c0c\\u0c0e-\\u0c10\\u0c12-\\u0c28\\u0c2a-\\u0c39\\u0c3d\\u0c58-\\u0c5a\\u0c60\\u0c61\\u0c80\\u0c85-\\u0c8c\\u0c8e-\\u0c90\\u0c92-\\u0ca8\\u0caa-\\u0cb3\\u0cb5-\\u0cb9\\u0cbd\\u0cde\\u0ce0\\u0ce1\\u0cf1\\u0cf2\\u0d05-\\u0d0c\\u0d0e-\\u0d10\\u0d12-\\u0d3a\\u0d3d\\u0d4e\\u0d54-\\u0d56\\u0d5f-\\u0d61\\u0d7a-\\u0d7f\\u0d85-\\u0d96\\u0d9a-\\u0db1\\u0db3-\\u0dbb\\u0dbd\\u0dc0-\\u0dc6\\u0e01-\\u0e30\\u0e32\\u0e33\\u0e40-\\u0e46\\u0e81\\u0e82\\u0e84\\u0e87\\u0e88\\u0e8a\\u0e8d\\u0e94-\\u0e97\\u0e99-\\u0e9f\\u0ea1-\\u0ea3\\u0ea5\\u0ea7\\u0eaa\\u0eab\\u0ead-\\u0eb0\\u0eb2\\u0eb3\\u0ebd\\u0ec0-\\u0ec4\\u0ec6\\u0edc-\\u0edf\\u0f00\\u0f40-\\u0f47\\u0f49-\\u0f6c\\u0f88-\\u0f8c\\u1000-\\u102a\\u103f\\u1050-\\u1055\\u105a-\\u105d\\u1061\\u1065\\u1066\\u106e-\\u1070\\u1075-\\u1081\\u108e\\u10a0-\\u10c5\\u10c7\\u10cd\\u10d0-\\u10fa\\u10fc-\\u1248\\u124a-\\u124d\\u1250-\\u1256\\u1258\\u125a-\\u125d\\u1260-\\u1288\\u128a-\\u128d\\u1290-\\u12b0\\u12b2-\\u12b5\\u12b8-\\u12be\\u12c0\\u12c2-\\u12c5\\u12c8-\\u12d6\\u12d8-\\u1310\\u1312-\\u1315\\u1318-\\u135a\\u1380-\\u138f\\u13a0-\\u13f5\\u13f8-\\u13fd\\u1401-\\u166c\\u166f-\\u167f\\u1681-\\u169a\\u16a0-\\u16ea\\u16ee-\\u16f8\\u1700-\\u170c\\u170e-\\u1711\\u1720-\\u1731\\u1740-\\u1751\\u1760-\\u176c\\u176e-\\u1770\\u1780-\\u17b3\\u17d7\\u17dc\\u1820-\\u1877\\u1880-\\u18a8\\u18aa\\u18b0-\\u18f5\\u1900-\\u191e\\u1950-\\u196d\\u1970-\\u1974\\u1980-\\u19ab\\u19b0-\\u19c9\\u1a00-\\u1a16\\u1a20-\\u1a54\\u1aa7\\u1b05-\\u1b33\\u1b45-\\u1b4b\\u1b83-\\u1ba0\\u1bae\\u1baf\\u1bba-\\u1be5\\u1c00-\\u1c23\\u1c4d-\\u1c4f\\u1c5a-\\u1c7d\\u1c80-\\u1c88\\u1ce9-\\u1cec\\u1cee-\\u1cf1\\u1cf5\\u1cf6\\u1d00-\\u1dbf\\u1e00-\\u1f15\\u1f18-\\u1f1d\\u1f20-\\u1f45\\u1f48-\\u1f4d\\u1f50-\\u1f57\\u1f59\\u1f5b\\u1f5d\\u1f5f-\\u1f7d\\u1f80-\\u1fb4\\u1fb6-\\u1fbc\\u1fbe\\u1fc2-\\u1fc4\\u1fc6-\\u1fcc\\u1fd0-\\u1fd3\\u1fd6-\\u1fdb\\u1fe0-\\u1fec\\u1ff2-\\u1ff4\\u1ff6-\\u1ffc\\u2071\\u207f\\u2090-\\u209c\\u2102\\u2107\\u210a-\\u2113\\u2115\\u2118-\\u211d\\u2124\\u2126\\u2128\\u212a-\\u2139\\u213c-\\u213f\\u2145-\\u2149\\u214e\\u2160-\\u2188\\u2c00-\\u2c2e\\u2c30-\\u2c5e\\u2c60-\\u2ce4\\u2ceb-\\u2cee\\u2cf2\\u2cf3\\u2d00-\\u2d25\\u2d27\\u2d2d\\u2d30-\\u2d67\\u2d6f\\u2d80-\\u2d96\\u2da0-\\u2da6\\u2da8-\\u2dae\\u2db0-\\u2db6\\u2db8-\\u2dbe\\u2dc0-\\u2dc6\\u2dc8-\\u2dce\\u2dd0-\\u2dd6\\u2dd8-\\u2dde\\u3005-\\u3007\\u3021-\\u3029\\u3031-\\u3035\\u3038-\\u303c\\u3041-\\u3096\\u309b-\\u309f\\u30a1-\\u30fa\\u30fc-\\u30ff\\u3105-\\u312d\\u3131-\\u318e\\u31a0-\\u31ba\\u31f0-\\u31ff\\u3400-\\u4db5\\u4e00-\\u9fd5\\ua000-\\ua48c\\ua4d0-\\ua4fd\\ua500-\\ua60c\\ua610-\\ua61f\\ua62a\\ua62b\\ua640-\\ua66e\\ua67f-\\ua69d\\ua6a0-\\ua6ef\\ua717-\\ua71f\\ua722-\\ua788\\ua78b-\\ua7ae\\ua7b0-\\ua7b7\\ua7f7-\\ua801\\ua803-\\ua805\\ua807-\\ua80a\\ua80c-\\ua822\\ua840-\\ua873\\ua882-\\ua8b3\\ua8f2-\\ua8f7\\ua8fb\\ua8fd\\ua90a-\\ua925\\ua930-\\ua946\\ua960-\\ua97c\\ua984-\\ua9b2\\ua9cf\\ua9e0-\\ua9e4\\ua9e6-\\ua9ef\\ua9fa-\\ua9fe\\uaa00-\\uaa28\\uaa40-\\uaa42\\uaa44-\\uaa4b\\uaa60-\\uaa76\\uaa7a\\uaa7e-\\uaaaf\\uaab1\\uaab5\\uaab6\\uaab9-\\uaabd\\uaac0\\uaac2\\uaadb-\\uaadd\\uaae0-\\uaaea\\uaaf2-\\uaaf4\\uab01-\\uab06\\uab09-\\uab0e\\uab11-\\uab16\\uab20-\\uab26\\uab28-\\uab2e\\uab30-\\uab5a\\uab5c-\\uab65\\uab70-\\uabe2\\uac00-\\ud7a3\\ud7b0-\\ud7c6\\ud7cb-\\ud7fb\\uf900-\\ufa6d\\ufa70-\\ufad9\\ufb00-\\ufb06\\ufb13-\\ufb17\\ufb1d\\ufb1f-\\ufb28\\ufb2a-\\ufb36\\ufb38-\\ufb3c\\ufb3e\\ufb40\\ufb41\\ufb43\\ufb44\\ufb46-\\ufbb1\\ufbd3-\\ufd3d\\ufd50-\\ufd8f\\ufd92-\\ufdc7\\ufdf0-\\ufdfb\\ufe70-\\ufe74\\ufe76-\\ufefc\\uff21-\\uff3a\\uff41-\\uff5a\\uff66-\\uffbe\\uffc2-\\uffc7\\uffca-\\uffcf\\uffd2-\\uffd7\\uffda-\\uffdc";
  private static final String nonASCIIidentifierChars =
      "\\u200c\\u200d\\xb7\\u0300-\\u036f\\u0387\\u0483-\\u0487\\u0591-\\u05bd\\u05bf\\u05c1\\u05c2\\u05c4\\u05c5\\u05c7\\u0610-\\u061a\\u064b-\\u0669\\u0670\\u06d6-\\u06dc\\u06df-\\u06e4\\u06e7\\u06e8\\u06ea-\\u06ed\\u06f0-\\u06f9\\u0711\\u0730-\\u074a\\u07a6-\\u07b0\\u07c0-\\u07c9\\u07eb-\\u07f3\\u0816-\\u0819\\u081b-\\u0823\\u0825-\\u0827\\u0829-\\u082d\\u0859-\\u085b\\u08d4-\\u08e1\\u08e3-\\u0903\\u093a-\\u093c\\u093e-\\u094f\\u0951-\\u0957\\u0962\\u0963\\u0966-\\u096f\\u0981-\\u0983\\u09bc\\u09be-\\u09c4\\u09c7\\u09c8\\u09cb-\\u09cd\\u09d7\\u09e2\\u09e3\\u09e6-\\u09ef\\u0a01-\\u0a03\\u0a3c\\u0a3e-\\u0a42\\u0a47\\u0a48\\u0a4b-\\u0a4d\\u0a51\\u0a66-\\u0a71\\u0a75\\u0a81-\\u0a83\\u0abc\\u0abe-\\u0ac5\\u0ac7-\\u0ac9\\u0acb-\\u0acd\\u0ae2\\u0ae3\\u0ae6-\\u0aef\\u0b01-\\u0b03\\u0b3c\\u0b3e-\\u0b44\\u0b47\\u0b48\\u0b4b-\\u0b4d\\u0b56\\u0b57\\u0b62\\u0b63\\u0b66-\\u0b6f\\u0b82\\u0bbe-\\u0bc2\\u0bc6-\\u0bc8\\u0bca-\\u0bcd\\u0bd7\\u0be6-\\u0bef\\u0c00-\\u0c03\\u0c3e-\\u0c44\\u0c46-\\u0c48\\u0c4a-\\u0c4d\\u0c55\\u0c56\\u0c62\\u0c63\\u0c66-\\u0c6f\\u0c81-\\u0c83\\u0cbc\\u0cbe-\\u0cc4\\u0cc6-\\u0cc8\\u0cca-\\u0ccd\\u0cd5\\u0cd6\\u0ce2\\u0ce3\\u0ce6-\\u0cef\\u0d01-\\u0d03\\u0d3e-\\u0d44\\u0d46-\\u0d48\\u0d4a-\\u0d4d\\u0d57\\u0d62\\u0d63\\u0d66-\\u0d6f\\u0d82\\u0d83\\u0dca\\u0dcf-\\u0dd4\\u0dd6\\u0dd8-\\u0ddf\\u0de6-\\u0def\\u0df2\\u0df3\\u0e31\\u0e34-\\u0e3a\\u0e47-\\u0e4e\\u0e50-\\u0e59\\u0eb1\\u0eb4-\\u0eb9\\u0ebb\\u0ebc\\u0ec8-\\u0ecd\\u0ed0-\\u0ed9\\u0f18\\u0f19\\u0f20-\\u0f29\\u0f35\\u0f37\\u0f39\\u0f3e\\u0f3f\\u0f71-\\u0f84\\u0f86\\u0f87\\u0f8d-\\u0f97\\u0f99-\\u0fbc\\u0fc6\\u102b-\\u103e\\u1040-\\u1049\\u1056-\\u1059\\u105e-\\u1060\\u1062-\\u1064\\u1067-\\u106d\\u1071-\\u1074\\u1082-\\u108d\\u108f-\\u109d\\u135d-\\u135f\\u1369-\\u1371\\u1712-\\u1714\\u1732-\\u1734\\u1752\\u1753\\u1772\\u1773\\u17b4-\\u17d3\\u17dd\\u17e0-\\u17e9\\u180b-\\u180d\\u1810-\\u1819\\u18a9\\u1920-\\u192b\\u1930-\\u193b\\u1946-\\u194f\\u19d0-\\u19da\\u1a17-\\u1a1b\\u1a55-\\u1a5e\\u1a60-\\u1a7c\\u1a7f-\\u1a89\\u1a90-\\u1a99\\u1ab0-\\u1abd\\u1b00-\\u1b04\\u1b34-\\u1b44\\u1b50-\\u1b59\\u1b6b-\\u1b73\\u1b80-\\u1b82\\u1ba1-\\u1bad\\u1bb0-\\u1bb9\\u1be6-\\u1bf3\\u1c24-\\u1c37\\u1c40-\\u1c49\\u1c50-\\u1c59\\u1cd0-\\u1cd2\\u1cd4-\\u1ce8\\u1ced\\u1cf2-\\u1cf4\\u1cf8\\u1cf9\\u1dc0-\\u1df5\\u1dfb-\\u1dff\\u203f\\u2040\\u2054\\u20d0-\\u20dc\\u20e1\\u20e5-\\u20f0\\u2cef-\\u2cf1\\u2d7f\\u2de0-\\u2dff\\u302a-\\u302f\\u3099\\u309a\\ua620-\\ua629\\ua66f\\ua674-\\ua67d\\ua69e\\ua69f\\ua6f0\\ua6f1\\ua802\\ua806\\ua80b\\ua823-\\ua827\\ua880\\ua881\\ua8b4-\\ua8c5\\ua8d0-\\ua8d9\\ua8e0-\\ua8f1\\ua900-\\ua909\\ua926-\\ua92d\\ua947-\\ua953\\ua980-\\ua983\\ua9b3-\\ua9c0\\ua9d0-\\ua9d9\\ua9e5\\ua9f0-\\ua9f9\\uaa29-\\uaa36\\uaa43\\uaa4c\\uaa4d\\uaa50-\\uaa59\\uaa7b-\\uaa7d\\uaab0\\uaab2-\\uaab4\\uaab7\\uaab8\\uaabe\\uaabf\\uaac1\\uaaeb-\\uaaef\\uaaf5\\uaaf6\\uabe3-\\uabea\\uabec\\uabed\\uabf0-\\uabf9\\ufb1e\\ufe00-\\ufe0f\\ufe20-\\ufe2f\\ufe33\\ufe34\\ufe4d-\\ufe4f\\uff10-\\uff19\\uff3f";

  private static Pattern nonASCIIidentifierStartPattern;
  private static Pattern nonASCIIidentifierPattern;

  private static Pattern nonASCIIidentifierStart() {
    if (nonASCIIidentifierStartPattern == null)
      nonASCIIidentifierStartPattern = Pattern.compile("[" + nonASCIIidentifierStartChars + "]");
    return nonASCIIidentifierStartPattern;
  }

  private static Pattern nonASCIIidentifier() {
    if (nonASCIIidentifierPattern == null)
      nonASCIIidentifierPattern =
          Pattern.compile("[" + nonASCIIidentifierStartChars + nonASCIIidentifierChars + "]");
    return nonASCIIidentifierPattern;
  }

  // These are a run-length and offset encoded representation of the
  // >0xffff code points that are a valid part of identifiers. The
  // offset starts at 0x10000, and each pair of numbers represents an
  // offset to the next range, and then a size of the range. They were
  // generated by bin/generate-identifier-regex.js
  private static final int[] astralIdentifierStartCodes = {
    0, 11, 2, 25, 2, 18, 2, 1, 2, 14, 3, 13, 35, 122, 70, 52, 268, 28, 4, 48, 48, 31, 17, 26, 6, 37,
    11, 29, 3, 35, 5, 7, 2, 4, 43, 157, 19, 35, 5, 35, 5, 39, 9, 51, 157, 310, 10, 21, 11, 7, 153,
    5, 3, 0, 2, 43, 2, 1, 4, 0, 3, 22, 11, 22, 10, 30, 66, 18, 2, 1, 11, 21, 11, 25, 71, 55, 7, 1,
    65, 0, 16, 3, 2, 2, 2, 26, 45, 28, 4, 28, 36, 7, 2, 27, 28, 53, 11, 21, 11, 18, 14, 17, 111, 72,
    56, 50, 14, 50, 785, 52, 76, 44, 33, 24, 27, 35, 42, 34, 4, 0, 13, 47, 15, 3, 22, 0, 2, 0, 36,
    17, 2, 24, 85, 6, 2, 0, 2, 3, 2, 14, 2, 9, 8, 46, 39, 7, 3, 1, 3, 21, 2, 6, 2, 1, 2, 4, 4, 0,
    19, 0, 13, 4, 159, 52, 19, 3, 54, 47, 21, 1, 2, 0, 185, 46, 42, 3, 37, 47, 21, 0, 60, 42, 86,
    25, 391, 63, 32, 0, 449, 56, 264, 8, 2, 36, 18, 0, 50, 29, 881, 921, 103, 110, 18, 195, 2749,
    1070, 4050, 582, 8634, 568, 8, 30, 114, 29, 19, 47, 17, 3, 32, 20, 6, 18, 881, 68, 12, 0, 67,
    12, 65, 0, 32, 6124, 20, 754, 9486, 1, 3071, 106, 6, 12, 4, 8, 8, 9, 5991, 84, 2, 70, 2, 1, 3,
    0, 3, 1, 3, 3, 2, 11, 2, 0, 2, 6, 2, 64, 2, 3, 3, 7, 2, 6, 2, 27, 2, 3, 2, 4, 2, 0, 4, 6, 2,
    339, 3, 24, 2, 24, 2, 30, 2, 24, 2, 30, 2, 24, 2, 30, 2, 24, 2, 30, 2, 24, 2, 7, 4149, 196, 60,
    67, 1213, 3, 2, 26, 2, 1, 2, 0, 3, 0, 2, 9, 2, 3, 2, 0, 2, 0, 7, 0, 5, 0, 2, 0, 2, 0, 2, 2, 2,
    1, 2, 0, 3, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 1, 2, 0, 3, 3, 2, 6, 2, 3, 2, 3, 2, 0, 2, 9, 2, 16, 6,
    2, 2, 4, 2, 16, 4421, 42710, 42, 4148, 12, 221, 3, 5761, 10591, 541
  };
  private static final int[] astralIdentifierCodes = {
    509, 0, 227, 0, 150, 4, 294, 9, 1368, 2, 2, 1, 6, 3, 41, 2, 5, 0, 166, 1, 1306, 2, 54, 14, 32,
    9, 16, 3, 46, 10, 54, 9, 7, 2, 37, 13, 2, 9, 52, 0, 13, 2, 49, 13, 10, 2, 4, 9, 83, 11, 7, 0,
    161, 11, 6, 9, 7, 3, 57, 0, 2, 6, 3, 1, 3, 2, 10, 0, 11, 1, 3, 6, 4, 4, 193, 17, 10, 9, 87, 19,
    13, 9, 214, 6, 3, 8, 28, 1, 83, 16, 16, 9, 82, 12, 9, 9, 84, 14, 5, 9, 423, 9, 838, 7, 2, 7, 17,
    9, 57, 21, 2, 13, 19882, 9, 135, 4, 60, 6, 26, 9, 1016, 45, 17, 3, 19723, 1, 5319, 4, 4, 5, 9,
    7, 3, 6, 31, 3, 149, 2, 1418, 49, 513, 54, 5, 49, 9, 0, 15, 0, 23, 4, 2, 14, 1361, 6, 2, 16, 3,
    6, 2, 1, 2, 4, 2214, 6, 110, 6, 6, 9, 792487, 239
  };

  // This has a complexity linear to the value of the code. The
  // assumption is that looking up astral identifier characters is
  // rare.
  private static boolean isInAstralSet(int code, int[] set) {
    int pos = 0x10000;
    for (int i = 0; i < set.length; i += 2) {
      pos += set[i];
      if (pos > code) return false;
      pos += set[i + 1];
      if (pos >= code) return true;
    }
    return false;
  }

  // Test whether a given character code starts an identifier.

  public static boolean isIdentifierStart(int code, boolean astral) {
    if (code < 65) return code == 36;
    if (code < 91) return true;
    if (code < 97) return code == 95;
    if (code < 123) return true;
    if (code <= 0xffff)
      return code >= 0xaa && nonASCIIidentifierStart().matcher(str(code)).matches();
    if (!astral) return false;
    return isInAstralSet(code, astralIdentifierStartCodes);
  }

  public static boolean isIdentifierChar(int code, boolean astral) {
    if (code < 48) return code == 36;
    if (code < 58) return true;
    if (code < 65) return false;
    if (code < 91) return true;
    if (code < 97) return code == 95;
    if (code < 123) return true;
    if (code <= 0xffff) return code >= 0xaa && nonASCIIidentifier().matcher(str(code)).matches();
    if (!astral) return false;
    return isInAstralSet(code, astralIdentifierStartCodes)
        || isInAstralSet(code, astralIdentifierCodes);
  }

  private static String str(int i) {
    return new String(Character.toChars(i));
  }
}
