[racket-users] plan to build a continuous integration system in racket
Hi, all I am a senior student and plan to build a continuous integration system using Racket as my graduation project. I'm very new to Racket web programming and CI/CD (about CI system I've already found some great projects to refer to). I've just gone through [Web Applications in Racket] and bought [Server: Racket]. Are there any other starter resources or experiences to share about the Racket web programming? Or maybe isn't it a good choice to dive into the web field using Racket? -- 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/3d98a427-f3a7-44d2-ad45-499a1f3cf83c%40googlegroups.com.
[racket-users] Re: How to convert String to Integer
I came to the following result as conversion function : #lang typed/racket (: string2value (-> String Integer)) (define (string2value astring) (define (fun [val : Char] [res : Integer]) (+ (* 10 res) (- (char->integer val) 48))) (foldl fun 0 (string->list astring)) ) (print (string2value "12345")) On Tuesday, February 11, 2020 at 11:34:16 AM UTC+1, Alain De Vos wrote: > > I tried the following function to conver a String to an Integer. > > #lang typed/racket > (: myconversion (-> String Integer)) > (define (myconversion str) > (string->number str)) > > The error given is : > Type Checker: type mismatch > expected: Integer > given: (U Complex False) in: (string->number str) > > I guess this is because a number is not an Integer. > > How to proceed? > > I found the following code on internet , but this looks like a real > overkill for this simple problem , > > (: numerical-char->integer (-> Char >Integer))(define (numerical-char->integer char) > (let ([num (- (char->integer char) 48)]) ; 48 = (char->integer #\0) > (if > (or (< num 0) (> num 9)) > (raise 'non-numerical-char #t) > num))) > (: string->integer (-> String >Integer))(define (string->integer str) > (let ([char-list (string->list str)]) > (if (null? char-list) > (raise 'empty-string #t) > (foldl > (λ([x : Integer] [y : Integer]) >(+ (* y 10) x)) > 0 > (map numerical-char->integer char-list) > > -- 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/3e58a927-c05a-4688-984c-1750fb014624%40googlegroups.com.
[racket-users] USB serial port error
Hello all, I'm trying to get racket to talk to a virtual serial port on windows 10, and I've previously used code based on this email thread https://lists.racket-lang.org/users/archive/2014-September/064136.html It used to work and now for some reason it fails with an error 87 when I try to read from the input port. Did something change/break in windows or racket? It's been a while since I needed to use the serial port in Racket so it may be something on my end. -- 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/1c49a76b-ea6f-4116-a939-6caa23c5353d%40googlegroups.com.
