function match_bitapScore_(e, x) {
    var accuracy = e / pattern.length;
    var proximity = Math.abs(loc - x);
    if (!dmp.Match_Distance) {
      // Dodge divide by zero error.
      return proximity ? 1.0 : accuracy;
    }
    return accuracy + (proximity / dmp.Match_Distance);
  }
Compute and return the score for a match with e errors and x location.
Accesses loc and pattern through being a closure.
@param {number} e Number of errors in match.
@param {number} x Location of match.
@return {number} Overall score for match (0.0 = good, 1.0 = bad).
@private