score_substring.rb

      indices = [candidate.index(/\b#{this_query_char}/),
                 candidate.index(this_query_char)]
      scores = [1, indices[1] + 1]

      indices.zip(scores).map { |index, score_delta|
        if index
          candidate_remainder = candidate[(index + 1)..-1]
          score = score_substring(candidate_remainder, query_remainder)
          if score
            score + score_delta
          end
        end
      }.compact.min