[racket-dev] raco make cannot marshal value error

I agree that it's a bug, in a sense, that your program runs even though
it cannot be compiled.

This is an example of "3-D syntax": you're embedding a value (i.e., an
instance of `s') that you can't write as a literal into the result of a
macro expansion. I think 3-D syntax probably should not be allowed, but
the macro system currently allows it.

Most likely, using 3-D syntax is a bad idea. It's possible that you
want to replace `#:transparent' with `#:prefab' in your example, since
a prefab structure can be written as a literal. More likely, I think
you want to generate an expression that constructs an `s' instead of
generating an `s' instance in the macro expansion.

At Thu, 26 Jul 2012 14:59:41 +0200, Tobias Hammer wrote:
> Hi,
> 
> i have the following two files, one that only requires the other and
> calls a macro and the other one that defines that macro:
> 
> === main.rkt
> #lang racket
> 
> (require "err.rkt")
> (a)
> 
> === err.rkt
> #lang racket
> 
> (begin-for-syntax
>   (struct s (arg) #:transparent)
> 
>   (define (fun arg)
>     (printf "arg: ~a\n" arg)))
> 
> (define-syntax (a stx)
>    (syntax-case stx ()
>      [(_)
>       (with-syntax ([v #`#,(s 123)])
>         #'(begin
>             (begin-for-syntax
>              (fun v))))]))
> 
> (provide a)
> 
> When executing 'racket main.rkt' directly i get the expected output
> arg: #(struct:s 123)
> but when i try to call 'raco make main.rkt' instead, i get this strange
> error:
> 
> arg: #(struct:s 123)
> write: cannot marshal value that is embedded in compiled code
>    value: (s 123)
>    context...:
>     /home_local/hamm_to/racket/racket-5.3.0.16/collects/compiler/cm.rkt:388:6
>     
> /home_local/hamm_to/racket/racket-5.3.0.16/collects/racket/private/more-scheme.r
> kt:151:2:  
> call-with-break-parameterization
>     /home_local/hamm_to/racket/racket-5.3.0.16/collects/compiler/cm.rkt:188:5
>     /home_local/hamm_to/racket/racket-5.3.0.16/collects/compiler/cm.rkt:508:26
>     /home_local/hamm_to/racket/racket-5.3.0.16/collects/compiler/cm.rkt:501:42
>     /home_local/hamm_to/racket/racket-5.3.0.16/collects/compiler/cm.rkt:466:0:  
> maybe-compile-zo
>     /home_local/hamm_to/racket/racket-5.3.0.16/collects/compiler/cm.rkt:579:2:  
> do-check
>     /home_local/hamm_to/racket/racket-5.3.0.16/collects/compiler/cm.rkt:653:4
>     
> /home_local/hamm_to/racket/racket-5.3.0.16/collects/compiler/commands/make.rkt:7
> 7:8:  
> for-loop
>     
> /home_local/hamm_to/racket/racket-5.3.0.16/collects/compiler/commands/make.rkt: 
>  
> [running body]
>     /home_local/hamm_to/racket/racket-5.3.0.16/collects/raco/raco.rkt:  
> [running body]
>     /home_local/hamm_to/racket/racket-5.3.0.16/collects/raco/main.rkt:  
> [running body]
> 
> I think i need a little help to understand what is happening here
> and what i am doing wrong. I had expected that running and compiling
> works on the same set of programs.
> 
> Thanks for any clarification.
> 
> Tobias
> 
> 
> 
> -- 
> ---------------------------------------------------------
> Tobias Hammer
> DLR / Institute of Robotics and Mechatronics
> Tel.: 08153/28-1487
> Mail: tobias.hammer at dlr.de
> _________________________
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