[racket] Evaluating code written in non-SEXP language

From: Dmitry Pavlov (dpavlov at ipa.nw.ru)
Date: Fri Sep 13 09:01:36 EDT 2013


Many thanks! Your code works perfectly for my program.

Now I would like to describe my tries to make a standalone
executable out of my program.

Most obvious way fails:

$ raco exe slon-main.rkt
$ ./slon-main
standard-module-name-resolver: collection not found
   collection: "slon"
   in collection directories:

Not surprising, as the "slon" collection is not mentioned
in the slon-main.rkt itself, but is required dynamically.

So my second thought was that maybe ++lib would help.
It did not. (Did I use the flag incorrectly?)

$ raco exe ++lib slon/slon-language slon-main.rkt
$ ./slon-main
<same error message>

Seeking for the solution, I upgraded from raco to the Racket level:

#lang racket
(require compiler/embed)

(create-embedding-executable "slon-main"
      #:modules '((#f slon/slon-main) (#f slon/slon-language))
        (parameterize ([current-namespace (make-base-namespace)])
                (compile `(namespace-require 'slon/slon-main)))
      #:configure-via-first-module? #t
      #:verbose? #t)

That worked great. "slon-main" was able to run independently
of its own location in the file system, and indenendeltly
of the presence of the original files in the slon/ collection
on disk.

But there was another thing. In my implementation, I have
some binary data files that are loaded via

(define-runtime-path eop.era "../eop/eop.era")

The resulting program depended on those files. When I renamed
one of them, I got an error message:

$ ./slon-main
with-input-from-file: cannot open input file
   path: /home/dpavlov/era/slon/../eop/eop.era

"OK", I thought, "raco distribute is supposed to fix that".

$ raco distribute slon-distr slon-main
$ ls ./slon-distr/lib/plt/slon-main/exts/ert/home/dpavlov/era/eop/
$ ./slon-distr/bin/slon-main
standard-module-name-resolver: collection not found
   collection: "slon"
   in collection directories:

The executable "slon-main" produced by raco distrubute is
different from the original one (although the size is the same).
I guess, raco distribute have eliminated the dependency of the
binary files with absolute paths, but it reintroduced the
dependency on the "slon" collection, which I previously got
rid of with the help of (create-embedding-executable)!

And here I am stuck, asking for help.



On 09/13/2013 05:33 AM, Matthew Flatt wrote:
> I'm not sure I understand what you want, but here are some ideas about
> evaluating a text that would a module if only a "#lang" line were
> added.
> To start, here's a function to `require` an input port that contains a
> module's source. It uses the current namespace, and it gensyms a name
> for the module if you don't provide one. The part that I think is least
> obvious is using `current-module-declare-name` to set the name of the
> module to that it can be found by `dynamic-require`:
>   (require syntax/modread)
>   (define (require-input-port p [name (gensym)])
>     (define module-name (make-resolved-module-path name))
>     (parameterize ([current-module-declare-name module-name])
>       (eval-syntax (check-module-form ; ensures that `module` is bound
>                     (with-module-reading-parameterization
>                      (lambda ()
>                        (read-syntax (object-name p) p)))
>                     'ignored
>                     #f)))
>     (dynamic-require module-name #f))
> The `require-input-port` function assumes that the source starts with
> "#lang". You could use `input-port-append`, as others have suggested,
> to add a "#lang" line:
>   (define p (input-port-append #t
>                                (open-input-string "#lang racket/base\n")
>                                (open-input-file "body.rktd")))
>   (port-count-lines! p)
>   (require-input-port p)
> A problem with `input-port-append` is that line numbers are off by one
> for error reporting, and positions are off by the length of the first
> line. That's an annoyingly difficult problem to fix, but
> `prefix-input-port` below is my attempt (and maybe `input-port-append`
> should just work better along similar lines).
>   (define p (prefix-input-port #"#lang racket/base\n"
>                                (open-input-file "body.rktd")))
>   (port-count-lines! p)
>   (require-input-port p)
> ----------------------------------------
> ;; prefix-input-port : bytes input-port -> input-port
> ;;  Directs position requests to the given port after the
> ;;  prefix is read.
> ;;  Closes the given input port when the result port is closed.
> (define (prefix-input-port prefix base-p)
>    (define-values (prefix-i prefix-o) (make-pipe))
>    (write-bytes prefix prefix-o)
>    (close-output-port prefix-o)
>    (define (prefix-done?)
>      (zero? (pipe-content-length prefix-i)))
>    (make-input-port
>     (object-name base-p)
>     ;; read
>     (lambda (bstr)
>       (define n (read-bytes-avail!* bstr
>                                     (if (prefix-done?)
>                                         base-p
>                                         prefix-i)))
>       (if (equal? n 0)
>           (wrap-evt base-p (lambda (v) 0))
>           n))
>     ;; peek
>     (lambda (bstr offset evt)
>       (define pre-n (pipe-content-length prefix-i))
>       (define n (if (offset . >= . pre-n)
>                     (peek-bytes-avail!* bstr
>                                         (- offset pre-n)
>                                         #f
>                                         base-p)
>                     (peek-bytes-avail!* bstr
>                                         offset
>                                         #f
>                                         prefix-i)))
>       (if (equal? n 0)
>           (wrap-evt base-p (lambda (v) 0))
>           n))
>     ;; close
>     (lambda ()
>       (close-input-port base-p))
>     ;; get-progress-evt
>     ;;  Difficult (impossible?) to support at the
>     ;;  prefix--base boundary.
>     #f
>     ;; commit
>     #f
>     ;; get-location
>     (lambda ()
>       (if (prefix-done?)
>           (port-next-location base-p)
>           (port-next-location prefix-i)))
>     ;; count-lines!
>     (lambda ()
>       (port-count-lines! prefix-i)
>       (port-count-lines! base-p))))

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