Thanks for the feedback! I will study this code and make more functional Em dom, 17 de fev de 2019 22:13, Philip McGrath <phi...@philipmcgrath.com escreveu:
> Well, if you call `(exit 0)`, your Racket program really will exit with > code 0 without doing anything else: the function `exit` never returns, so, > in your case, `execute` never returns, `refine-main` never returns, and > Rackunit never gets a chance to look at any output it may or may not have > written. > > In my opinion, the best thing to do is not really to call `(exit 0)` from > `execute`. Here's one way to do it: > #lang racket > > (module+ test > (require rackunit)) > > ;; execute : string? -> (or/c #f (integer-in 0 255)) > ;; Interprets the given string, perhaps causing side-effects. > ;; Returns either: > ;; - an integer between 0 and 255, inclusive, > ;; meaning the program should exit immediately with that code > ;; - #f, meaning the program can accept more commands > (define (execute command) > (match command > [(pregexp #px"^exit\\s+(\\d+)$" > (list _ (app string->number code))) > code] > [command > (printf "command: ~v\n" command) > #f])) > > ;; refine-main : -> (integer-in 0 255) > ;; Interprets commands from (current-input-port), > ;; perhaps causing side-effects. > ;; Returns an exit code. > (define (refine-main) > (for/last ([command (in-lines)]) > (define code > (execute command)) > #:final code > (or code 0))) > > (module+ test > (check-equal? > (with-output-to-string > (λ () > (with-input-from-string "exit 0" > refine-main))) > "" > "Consigo sair antes de comecar o tutorial")) > > When you really do want to exit as soon as `refine-main` returns, you can > do that by just writing `(exit (refine-main))`. > > Technically this is not your only option. In fact, you may be wondering, > if `exit` does what I say it does, why does your program not quit DrRacket? > In fact, `exit` really calls the current exit handler > <https://docs.racket-lang.org/reference/Exiting.html>, and DrRacket sets > the exit handler, among other things, to prevent the programs it runs from > interfering with each other or itself. You could likewise parameterize the > exit handler around your call to define-main for testing purposes. > > However, I think this is a good example of why side-effects (like exiting) > are less good for testing than returning values. > > -Philip > > > On Sun, Feb 17, 2019 at 6:44 PM Joao Pedro Abreu De Souza < > jp_ab...@id.uff.br> wrote: > >> (define (refine-main) >> (display next-string) ;;feito >> (set! next-command (shell-parser (my-read-line))) ;;TODO my-read-line >> (execute next-command) ;;TODO execute >> (refine-main)) ;;feito >> >> This is refine-main >> >> "shell-parser" is just a PEG-based parser, that return a struct >> >> "execute" in the case of reading a "exit 0" just call (exit 0) >> >> >> Em dom, 17 de fev de 2019 às 16:07, Joao Pedro Abreu De Souza < >> jp_ab...@id.uff.br> escreveu: >> >>> Well, there's no imediate return, i need to type exit 0 to finally the >>> test works >>> >>> I am using read-line to read input. Today later I will post more code(of >>> refine-main). >>> >>> Thanks >>> >>> Em dom, 17 de fev de 2019 10:37, Greg Hendershott < >>> greghendersh...@gmail.com escreveu: >>> >>>> What does it do? Does `check-equal?` show a failure message? If so, >>>> what does it say? >>>> >>>> >>>> I don't know what `refine-main` does, but this simple version works for >>>> me: >>>> >>>> #lang racket >>>> >>>> (require rackunit) >>>> >>>> (define (refine-main) >>>> (display (read-line))) ;echo >>>> >>>> (check-equal? >>>> (with-output-to-string >>>> (lambda () >>>> (with-input-from-string "input" >>>> (lambda () >>>> (refine-main))))) >>>> "input") >>>> >>>> On Sun, Feb 17, 2019 at 12:35 AM Joao Pedro Abreu De Souza >>>> <jp_ab...@id.uff.br> wrote: >>>> > >>>> > Hi everyone. I have a test of a user-related function that I don't >>>> can see why don't work : >>>> > >>>> > #lang racket >>>> > >>>> > (require rackunit) >>>> > (require "../../main.rkt") >>>> > >>>> > >>>> > >>>> > >>>> > (check-equal? >>>> > (with-output-to-string (lambda () >>>> > (with-input-from-string >>>> > "exit 0" >>>> > (lambda () (refine-main))))) >>>> > "" >>>> > "Consigo sair antes de comecar o tutorial") >>>> > >>>> > >>>> > >>>> > >>>> > I think that this will call refine-main and, when refine-main do a >>>> readline, will receive "exit 0" as string, and when display something, will >>>> appear as return of with-output-to-string, but this code don't work :( >>>> > >>>> > -- >>>> > 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. >>>> > For more options, visit https://groups.google.com/d/optout. >>>> >>>> -- >>>> 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. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- >> 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. >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. 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