[racket] Call racket with long code from racket

As other people already said, this way of doing things is not the most "safe
and beautiful" way of getting what you need done.
If "long-code" is really long and important, I suggest investigating other
solutions.


As Eli pointed out there are many weird conventions to pay attention
depending on your shell.
When you pass the string with quotes as in your example, I get an error like
this: /bin/sh: Syntax error: EOF in backquote substitution
Because bash is waiting for a second `.

Using a string would also make it difficult to write strings, because you'd
need to escape the double-quotes "\"this is a string\"" (and they will most
likely conflict with your shell).

The code below will show how the external code will be called and the
stdout/stderr (so you can see what's going wrong).

Using a quoted form instead of a string hides the problem of having ` and '
and instead use quasiquote and quote.

[]'s

Rodolfo Carvalho



#lang racket
(define external-code (format  "/opt/racket/bin/racket -e \" ~a \""
                               '(begin
                                  (require mzlib/defmacro)
                                  (define-macro (my-when
                                                 test . body)
                                    `(if ,test (begin , at body) '()))
                                  (my-when #t '(5 6 7)))))


(displayln external-code)
(newline)

(display
 (string-join
  (let* ([p (process external-code)]
         [stdout (first p)]
         [stderr (fourth p)])
    (map port->string (list stdout stderr)))
  ""))



On Tue, Sep 13, 2011 at 08:22, Niitsuma Hirotaka <
hirotaka.niitsuma at gmail.com> wrote:

> > You could try something like this:
> > #lang racket
> > (require racket/system)
> > (display (port->string (car (process (format "racket -e '~a' " '(+ 2
> 3))))))
>
> That does not work in the following case
>
>  (display (port->string (car (process    (format  "racket -e \" ~a \" "
>                                                "
>                                                (require mzlib/defmacro)
>                                                (define-macro (my-when
> test . body)`(if ,test (begin , at body) '() ))
>                                 (my-when #t '(5 6 7))
>                                                "
>                                                )))))
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