fix lexer

src/lexer_generator.ml

@@ -361,23 +361,27 @@ type lexer_result =
 
 *)
 let to_lexer_result (d:dfa) (q: dfa_state) (w: char list): lexer_result =
-   let (_,f) = List.find (fun (state,_) -> Set.equal q state) d.dfa_final in
-   match f (string_of_char_list w) with
-      | None -> LRskip
-      | Some token -> LRtoken token
+  let result = List.find_opt (fun (state,_) -> Set.equal q state) d.dfa_final in
+  match result with
+  | None ->  LRerror
+  | Some (_,f) -> match f (string_of_char_list w) with
+     | None -> LRskip
+     | Some token -> LRtoken token
+
 
 
 let tokenize_one (d : dfa) (w: char list) : lexer_result * char list =
   let rec recognize (q: dfa_state) (w: char list)
       (current_word: char list) (last_accepted: lexer_result * char list)
     : lexer_result * char list =
-        let last_accepted' = (to_lexer_result d q current_word, w) in
+         let last_accepted' = (to_lexer_result d q current_word, w) in
          match w with
          | [] -> last_accepted'
          | lettre::r ->
             match d.dfa_step q lettre with
             | None -> last_accepted'
             | Some q' -> let new_current_word = current_word @ [lettre] in match to_lexer_result d q' new_current_word with
+               | LRerror -> recognize q' r (new_current_word) last_accepted'
                | lr -> recognize q' r (new_current_word) last_accepted'
   in
   recognize d.dfa_initial w [] (LRerror, w)
@@ -524,6 +528,9 @@ let nfa_of_list_regexp l =
 
 let dfa_of_list_regexp l =
   let n = nfa_of_list_regexp l in
+  let oc = open_out "/tmp/nfa.dot" in
+  nfa_to_dot oc n;
+  close_out oc;
   dfa_of_nfa n
 
 let tokenize_list_regexp l s =