Thank you very much! I didn't find struct-info function. This is enough for my needs.
Wed, 24 Sep 2014 00:22:28 -0300 от Gustavo Massaccesi <[email protected]>: > This code works, but it needs a lot more of error checking. > > It uses that all the built-in exceptions are transparent and that all > of them inherit from exn, so the first field is the message. > > ;--- > #lang racket > > (define (copy-struct/new-first str first) > (define-values (str-struct-info _) (struct-info str)) > (define str-maker (struct-type-make-constructor str-struct-info)) > (apply str-maker first (cdr (cdr (vector->list (struct->vector str)))))) > > (define (parse-item item) > (with-handlers ([exn? (lambda (e) (raise (copy-struct/new-first e > (format "At item ~a\n~a" item (exn-message e)))))]) > (cons 1 2 3) ;==> cons: arity mismatch; > #;(/ 1 0) ;==> /: division by zero > )) > > (parse-item "Hello") > ;--- > > Gustavo > > > > > On Wed, Sep 17, 2014 at 1:59 PM, Roman Klochkov <[email protected]> wrote: > > I'm writeing a parser. > > So I want to see in parser exception what happend and when (not only where). > > > > (define (parse-item item) > > (with-handlers ([exn? (lambda (e) (raise (struct-copy exn e [message > > (format "At item ~a\n~a" item (exn-message e))])))]) > > ....)) > > > > But this way I lose all exception types. Is there a way to change exception > > message, saving its type, except long copy/paste like > > (with-handlers ([exn:fail:contract:arity? (raise (struct-copy > > exn:fail:contract:arity ...))] > > [exn:fil:contract? (raise (struct-copy > > exn:fail:contract ...))] > > ...) > > ...) > > > > ? > > > > -- > > Roman Klochkov > > > > ____________________ > > Racket Users list: > > http://lists.racket-lang.org/users > > > -- Roman Klochkov ____________________ Racket Users list: http://lists.racket-lang.org/users
