iraikov / chicken-lexgen Goto Github PK

Hi, I am not sure whether I should expect backtracking to occur.

For instance, in this example

(import lexgen)

(define (err s)
  (print "lexical error on stream: " s)
  (list))

(lex (seq (star (range #\0 #\9)) (char #\2)) err "123")

I get the error

lexical error on stream: ((3 2 1) #!eof)

instead of getting the possible result:

((#\1 #\2) (#\3))

Hello.
Exists simple way for declaring and using lexer state? F.e. in JFlex i can write
<YYBEGIN> "." { yybegin(YYAFTERDOT); return 1}
<YYAFTERDOT> "." { yybegin(YYBEGIN); return 2}
this declaration return 1 on first dot and 2 on second.

How i can write it on lexgen?