Re: unhandled constant?

[Han-Wen Nienhuys]

Here is an example that shows better how things work, and what might
be the cause of my problems. Is it right that programmatically set
contents of "current-module" are not serialized into the compiled
file?

   (define (run-at-compile-time cmd)
     (module-define! (current-module) (string->symbol cmd) #t)
     (format (current-error-port) "I-am-called-at-compile-time ~a\n" cmd))

  (define (runtime-call cmd)
    (format (current-error-port) "I-am-called-at-runtime ~a\n" cmd)
    (format (current-error-port) "val ~a\n"
            (module-ref (current-module) (string->symbol cmd))))

  (defmacro foo (cmd . rest)
  (run-at-compile-time cmd)
  `(runtime-call ,cmd))

  (foo "xy")

$ guile1.8 ew.scm
I-am-called-at-compile-time xy
I-am-called-at-runtime xy
val #t

this is compatible with 2.2 without compilation,

$ GUILE_AUTO_COMPILE=0 guile2.2 ew.scm
I-am-called-at-compile-time xy
I-am-called-at-runtime xy
val #t

but compilation fails

$ GUILE_AUTO_COMPILE=1 guile2.2 ew.scm
;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
;;;       or pass the --no-auto-compile argument to disable.
;;; compiling /home/hanwen/vc/lilypond/ew.scm
;;; WARNING: compilation of /home/hanwen/vc/lilypond/ew.scm failed:
;;; Unbound variable: run-at-compile-time

$ guild2.2 compile ew.scm
Backtrace:
In system/base/target.scm:
     57:6 19 (with-target _ _)
In system/base/compile.scm:
..
Unbound variable: run-at-compile-time


If I encapsulate the run-at-compile-time definition with

 (eval-when
  (compile eval)

it works if I remove the module manipulation, but the module-ref
doesn't work. It looks like the settings from module-define! are not
serialized into the byte code, so I can't have code that relies on
correspondence between module-define driven from macros and module-ref
during evaluation.

[hanwen@localhost lilypond]$ guild2.2 compile ew.scm
I-am-called-at-compile-time xy
wrote 
`/home/hanwen/.cache/guile/ccache/2.2-LE-8-3.A/home/hanwen/vc/lilypond/ew.scm.go'
[hanwen@localhost lilypond]$ GUILE_AUTO_COMPILE=0 guile2.2 ew.scm
I-am-called-at-runtime xy
Backtrace:
           6 (apply-smob/1 #<catch-closure 56514b4c37a0>)
In ice-9/boot-9.scm:
    705:2  5 (call-with-prompt ("prompt") #<procedure 56514b4d5c60 …> …)
In ice-9/eval.scm:
    619:8  4 (_ #(#(#<directory (guile-user) 56514b591140>)))
In ice-9/boot-9.scm:
   2312:4  3 (save-module-excursion #<procedure 56514b54b330 at ice-…>)
  3832:12  2 (_)
In ew.scm:
    10:10  1 (runtime-call "xy")
In unknown file:
           0 (scm-error misc-error #f "~A ~S ~S ~S" ("No variabl…" …) …)

ERROR: In procedure scm-error:
No variable named xy in #<directory (guile-user) 56514b591140>

On Fri, Jan 31, 2020 at 9:01 PM Linus Björnstam
<address@hidden> wrote:
>
> Read the docs. That seems to be a documentation bug. Try fiddling with the 
> arguments to eval when and see if you can make it work.
>
> --
>   Linus Björnstam
>
> On Fri, 31 Jan 2020, at 20:17, Han-Wen Nienhuys wrote:
> > On Fri, Jan 31, 2020 at 7:20 PM Linus Björnstam
> > <address@hidden> wrote:
> > > I don't really understand your question. With defmacro and syntax-case 
> > > you can run arbitrary code. If you just output code that does 
> > > module-define! that won't be run until runtime, and thus you cannot 
> > > depend on the result of that module-define! during expansion. You can 
> > > however wrap it in an eval-when to solve that issue. That allows you to 
> > > specify when code gets run. With module-define! I personally find it all 
> > > a bit icky, but I usually stay as far away from phasing as I can :)
> >
> >  eval-when looks like it might be a solution to the puzzle , but
> > honestly, the doc at
> >
> > https://www.gnu.org/software/guile/manual/html_node/Eval-When.html
> >
> > has me mystified.  When I run the example through guile 2.2 and
> > display *compilation-date*,
> >
> > I get a different answer each time. Shouldn't it be a fixed timestamp
> > (of when the compile happened?)
> >
> > [hanwen@localhost lilypond]$ guile2.2 e.scm
> > ;;; note: source file /home/hanwen/vc/lilypond/e.scm
> > ;;;       newer than compiled
> > /home/hanwen/.cache/guile/ccache/2.2-LE-8-3.A/home/hanwen/vc/lilypond/e.scm.go
> > ;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
> > ;;;       or pass the --no-auto-compile argument to disable.
> > ;;; compiling /home/hanwen/vc/lilypond/e.scm
> > ;;; compiled
> > /home/hanwen/.cache/guile/ccache/2.2-LE-8-3.A/home/hanwen/vc/lilypond/e.scm.go
> > Fri Jan 31 20:15:57+0100 2020
> > [hanwen@localhost lilypond]$ guile2.2 e.scm
> > Fri Jan 31 20:15:58+0100 2020
> > [hanwen@localhost lilypond]$ guile2.2 e.scm
> > Fri Jan 31 20:16:00+0100 2020
> >
> > --
> > Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen
> >



-- 
Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen