levenshtein.hon commit switch: reject if some operation is in progress (c45f0f5)
   1#ifndef LEVENSHTEIN_H
   2#define LEVENSHTEIN_H
   3
   4int levenshtein(const char *string1, const char *string2,
   5        int swap_penalty, int substitution_penalty,
   6        int insertion_penalty, int deletion_penalty);
   7
   8#endif