talisman/stemmers/uea-lite.js

Straightforward fuzzy matching, information retrieval and NLP building blocks for JavaScript.

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: false
});
exports.withRule = withRule;
exports.default = ueaLite;

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

/**
 * Talisman stemmers/uea-lite
 * ===========================
 *
 * The University of East Anglia (UEA) Lite stemmer.
 *
 * [Reference]:
 * http://www2.cmp.uea.ac.uk/~djs/projects/UEAlite/stemmer.html
 * http://github.com/ealdent/uea-stemmer
 *
 * [Authors]:
 * Marie-CLaire Jenkins
 * Dan Smith
 * Jason M. Adams (Ruby version additions)
 */

/**
 * Rules.
 */
var PROBLEMS = new Set(['is', 'as', 'this', 'has', 'was', 'during', 'menses']);

var CONTRACTIONS = [[/n't/, ' not'], [/'ve/, ' have'], [/'re/, ' are'], [/'m/, ' am']];

var complexSuffixing = function complexSuffixing(word) {

  // Dropping final "s"
  if (word[word.length - 1] === 's') word = word.slice(0, -1);

  // Dropping "ing"
  if (word.slice(-3) === 'ing') word = word.slice(0, -3);

  // Dropping "ed"
  else if (word.slice(-2) === 'ed') word = word.slice(0, -2);

  // Dropping potential consecutive duplicate letters
  if (word[word.length - 1] === word[word.length - 2]) word = word.slice(0, -1);

  return word;
};

var RULES = [[/^\d+$/, null, '90.3'], [/^\w+-\w+$/, null, '90.2'], [/-/, null, '90.1'], [/_/, null, '90'], [/^[A-Z]+s$/, 1, '91.1'], [/^[A-Z]+$/, null, '91'], [/^(?:.*[A-Z].*[A-Z]|[A-Z]{1}).*$/, null, '92'], [/aceous$/, 6, '1'], [/ces$/, 1, '2'], [/cs$/, null, '3'], [/sis$/, null, '4'], [/tis$/, null, '5'], [/ss$/, null, '6'], [/eed$/, null, '7'], [/eeds$/, 1, '7'], [/ued$/, 1, '8'], [/ues$/, 1, '9'], [/ees$/, 1, '10'], [/iases$/, 2, '11.4'], [/uses$/, 1, '11.3'], [/sses$/, 2, 11.2], [/eses$/, 'esis', '11.1'], [/ses$/, 1, '11'], [/tled$/, 1, '12.5'], [/pled$/, 1, '12.4'], [/bled$/, 1, '12.3'], [/eled$/, 2, '12.2'], [/lled$/, 2, '12.1'], [/led$/, 2, '12'], [/ened$/, 2, '13.7'], [/ained$/, 2, '13.6'], [/erned$/, 2, '13.5'], [/rned$/, 2, '13.4'], [/nned$/, 3, '13.3'], [/oned$/, 2, '13.2'], [/gned$/, 2, '13.1'], [/ned$/, 1, '13'], [/ifted$/, 2, '14'], [/ected$/, 2, '15'], [/vided$/, 1, '16'], [/ved$/, 1, '17'], [/ced$/, 1, '18'],

//--< Jason M. Adams
[/arred$/, 3, '19.1'],
//--> Jason M. Adams

[/erred$/, 3, '19'], [/urred$/, 3, '20.5'], [/lored$/, 2, '20.4'], [/eared$/, 2, '20.3'], [/tored$/, 1, '20.2'], [/ered$/, 2, '20.1'], [/red$/, 1, '20'], [/reds$/, 2, '20'], [/tted$/, 3, '21'],

//--< Jason M. Adams
[/noted$/, 1, '22.6'], [/leted$/, 1, '22.5'], [/[^vm]ited$/, 2, '22.4'], [/(?:ch|[vm])i[td]ed$/, 1, '22.3'], [/uted$/, 1, '22.2'], [/ated$/, 1, '22.1'], [/ted$/, 2, '22'],
//--> Jason M. Adams

[/anges$/, 1, '23'], [/aining$/, 3, '24'], [/acting$/, 3, '25'], [/ttings?$/, 't', '26'], [/viding$/, 'vide', '27'], [/ssed$/, 2, '28'], [/sed$/, 1, '29'], [/titudes$/, 1, '30'],

//--< Jason M. Adams
[/oed$/, 1, '31.3'], [/d?oes$/, 2, '31.2'], [/[oaiu]ked$/, 1, '31.1'], [/[aiu]med/, 1, '31'],
//--> Jason M. Adams

[/ulted$/, 2, '32'], [/uming$/, 'ume', '33'], [/fulness$/, 4, '34'], [/ousness$/, 4, '35'], [/r[aeiou]bed$/, 1, '36.1'], [/beds?$/, 'b', '36'], [/ssings?$/, 'ss', '37'], [/ulting$/, 3, '38'], [/vings?$/, 'v', '39'], [/vings$/], [/eadings?$/, 'ead', '40.7'], [/oadings?$/, 'oad', '40.6'], [/edings?$/, 'ed', '40.5'], [/ddings?$/, 'd', '40.4'], [/ldings?$/, 'ld', '40.3'], [/rdings?$/, 'rd', '40.2'], [/ndings?$/, 'nd', '40.1'], [/dings?/, 'de', '40'], [/llings?$/, 'l', '41'], [/ealings?$/, 'eal', '42.4'], [/olings?$/, 'ol', '42.3'], [/ailings?$/, 'ail', '42.2'], [/elings?$/, 'el', '42.1'], [/lings?$/, 'le', '42'], [/nged$/, 1, '43.2'], [/gged$/, 3, '43.1'], [/ged$/, 1, '43'], [/mmings?$/, 'm', '44.3'], [/rming$/, 3, '44.2'], [/lming$/, 3, '44.1'], [/mings?$/, 'me', '44'], [/ngings?$/, 'ng', '45.2'], [/ggings?$/, 'g', '45.1'], [/gings?$/, 'ge', '45'], [/aning$/, 3, '46.6'], [/ening$/, 3, '46.5'], [/gning$/, 3, '46.4'], [/nning$/, 4, '46.3'], [/oning$/, 3, '46.2'], [/rning$/, 3, '46.1'], [/ning$/, 'ne', '46'], [/stings?$/, 'st', '47'], [/etings?$/, 'et', '48.4'], [/pting$/, 3, '48.3'], [/ntings?$/, 'nt', '48.2'], [/cting$/, 3, '48.1'], [/tings?$/, 'ct', '48.1'], [/ssed$/, 2, '49'], [/les$/, 1, '50'], [/tes$/, 1, '51'], [/zed$/, 1, '52'], [/lled$/, 2, '53'], [/irings?$/, 'ire', '54.4'], [/urings?$/, 'ure', '54.3'], [/ncings?$/, 'nce', '54.2'], [/zing$/, 3, '54.1'], [/sings?$/, 'se', '54'], [/lling$/, 3, '55'], [/ied$/, 'e', '56'], [/ating$/, 'ate', '57'],

//--< Jason M. Adams
[/dying$/, 'die', '58.2'], [/^lying$/, 'lie', '58.2'], [/tying$/, 'tie', '58.2'],
//--> Jason M. Adams

[/thing$/, null, '58.1'], [/things$/, 1, '58.1'], [/\w{2}ings?$/, complexSuffixing, '58'], [/ies$/, 'y', '59'], [/lves$/, 'lf', '60.1'], [/ves$/, 1, '60'], [/aped$/, 1, '61.3'], [/uded$/, 1, '61.2'], [/oded$/, 1, '61.1'],

// NOTE: same rule as 22.1, but present uselessly in all reference
// implementations
// [/ated$/, 1, '61'],
[/\w{2}eds?$/, complexSuffixing, '62'],

//--< Jason M. Adams
[/des$/, 1, '63.10'], [/res$/, 1, '63.9'],
//--> Jason M. Adams

[/pes$/, 1, '63.8'], [/mes$/, 1, '63.7'], [/ones$/, 1, '63.6'], [/izes$/, 1, '63.5'], [/ures$/, 1, '63.4'], [/ines$/, 1, '63.3'], [/ides$/, 1, '63.2'],

//--< Jason M. Adams
[/[kg]es$/, 1, '63.1'],
//--> Jason M. Adam

[/es$/, 2, '63'], [/is$/, 'e', '64'], [/ous$/, null, '65'], [/ums$/, null, '66'], [/us$/, null, '67'], [/s$/, 1, '68']];

/**
 * Function stemming the given world using the UEALite stemmer.
 *
 * @param  {string} word - The word to stem.
 * @return {object}      - An object containing the stemmed word and the applied
 *                         rule.
 */
function withRule(word) {
  var stem = word;

  // Is the given word problematic?
  if (PROBLEMS.has(word)) return { rule: '90', stem: stem };

  // If the word contains apostrophe(s)
  if (/'/.test(word)) {

    // Possessive (both singular & plural)
    if (/'s?$/i.test(word)) stem = stem.replace(/'s?$/i, '');

    // Expand various contractions
    for (var i = 0, l = CONTRACTIONS.length; i < l; i++) {
      var _stem;

      stem = (_stem = stem).replace.apply(_stem, _toConsumableArray(CONTRACTIONS[i]));
    }return { rule: '94', stem: stem };
  }

  // Applying rules
  for (var _i = 0, _l = RULES.length; _i < _l; _i++) {
    var _RULES$_i = RULES[_i],
        pattern = _RULES$_i[0],
        replacement = _RULES$_i[1],
        rule = _RULES$_i[2];

    // Replacing through string

    if (typeof replacement === 'string') {
      var newStem = stem.replace(pattern, replacement);

      if (newStem !== stem) return { rule: rule, stem: newStem };
    }

    // Attempting to match the pattern
    if (pattern.test(stem)) {

      if (typeof replacement === 'function') stem = replacement(stem);else if (replacement) stem = stem.slice(0, -replacement);

      return { rule: rule, stem: stem };
    }
  }

  return { rule: '0', stem: word };
}

function ueaLite(word) {
  return withRule(word).stem;
}
module.exports = exports['default'];
exports['default'].withRule = exports.withRule;