compromise/src/terms/tagger/contraction/02-hardOne.js

natural language processing in the browser

'use strict';
const fixContraction = require('./fix');


//these are always contractions
// const blacklist = {
//   'it\'s': true,
//   'that\'s': true
// };

// //rocket's red glare
// if (nextWord.tag['Adjective'] && terms.get(x + 2) && terms.get(x + 2).tag['Noun']) {
//   return true;
// }
// //next word is an adjective
// if (nextWord.tag['Adjective'] || nextWord.tag['Verb'] || nextWord.tag['Adverb']) {
//   return false;
// }



// "'s" may be a contraction or a possessive
// 'spencer's house' vs 'spencer's good'
const isPossessive = (ts, i) => {
  let t = ts.terms[i];
  let next_t = ts.terms[i + 1];
  //a pronoun can't be possessive - "he's house"
  if (t.tag.Pronoun || t.tag.QuestionWord) {
    return false;
  }
  //if end of sentence, it is possessive - "was spencer's"
  if (!next_t) {
    return true;
  }
  //a gerund suggests 'is walking'
  if (next_t.tag.VerbPhrase) {
    return false;
  }
  //spencer's house
  if (next_t.tag.Noun) {
    return true;
  }
  //rocket's red glare
  if (next_t.tag.Adjective && ts.terms[i + 2] && ts.terms[i + 2].tag.Noun) {
    return true;
  }
  //an adjective suggests 'is good'
  if (next_t.tag.Adjective || next_t.tag.Adverb || next_t.tag.Verb) {
    return false;
  }
  return false;
};


//handle ambigous contraction "'s"
const hardOne = (ts) => {
  for(let i = 0; i < ts.terms.length; i++) {
    //skip existing
    if (ts.terms[i].silent_term) {
      continue;
    }
    let parts = ts.terms[i].term.contraction();
    if (parts) {
      //have we found a hard one
      if (parts.end === 's') {
        //spencer's house
        if (isPossessive(ts, i)) {
          ts.terms[i].tagAs('#Possessive', 'hard-contraction');
          // console.log('==possessive==');
          continue;
        }
        //is vs was
        let arr = [parts.start, 'is'];
        ts = fixContraction(ts, arr, i);
        i += 1;
      }
    }
  }
  return ts;
};

module.exports = hardOne;