Jens answered your question, but I'll note two convenient shorthands: > #lang racket > (require racket/format)
racket/format is provided by #lang racket, so you can skip that. This: (define fp (lambda (s n) (string-append (pp_number n) " + " s))) is the same as this: (define (fp s n) (string-append (pp_number n) " + " s))) On Tue, Dec 14, 2021 at 1:48 PM Cyrille DEUSS <cyrille.de...@gmail.com> wrote: > #lang racket > (require racket/format) > > (define pp_number > (lambda (n) > (~a n #:width 6 #:align 'right #:left-pad-string "0"))) > > (define fp > (lambda (s n) > (string-append (pp_number n) " + " s))) > > (define f > (lambda (s n) > (format "~a + ~a" n s))) > > (foldl f "" '(1 2 3)) > ; works great ! > > (foldl fp "" '(1 2 3)) > ; and why not this one ? > > Thanks in advance. > Cyrille > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to racket-users+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/e72b954e-0b48-4830-b253-34b904d726bcn%40googlegroups.com > <https://groups.google.com/d/msgid/racket-users/e72b954e-0b48-4830-b253-34b904d726bcn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/CAE8gKoeiVYvsCFuJgHYvK9Eg7cDpSTAkGpk4h2x8aNoe8YHOzg%40mail.gmail.com.