function _identifiers (options) {
  var query = {}

  for (var prop in options.hash) {
    if (/^-/.test(prop)) {
      query[prop.replace(/^-/, '!')] = options.hash[prop]
    } else if (/^_/.test(prop)) {
      query[prop.replace(/^_/, '')] = new RegExp(options.hash[prop])
    } else {
      query[prop] = options.hash[prop]
    }
  }
  return arrayify(options.data.root).filter(where(query)).filter(function (doclet) {
    return !doclet.ignore && (state.options.private ? true : doclet.access !== 'private')
  })
}
Returns an array of identifiers matching the query
@returns {array}
@static