Help to TeXmacs with Guile 2

Help to TeXmacs with Guile 2

[Germán Arias]

Hi,

I don't have experience with macros. But I get this error trying TeXmacs with Guile 2.x:

 ERROR: Syntax error:
;;; kernel/boot/boot.scm:57:4: definition in expression context, where definitions are not allowed, in form (define-syntax define-public-macro (lambda (y) #f #((macro-type . defmacro) (defmacro-args args)) (syntax-case y () ((_ . args) (let ((v (syntax->datum (syntax args)))) (datum->syntax y (apply (lambda (head . body) (quasiquote (define-public (unquote (car head)) (procedure->memoizing-macro (lambda (cmd env) (apply (lambda (unquote (cdr head)) (unquote-splicing body)) (cdr cmd))))))) v)))))))

The offending code is:

(if (guile-a?)
    (define-macro (define-public-macro head . body)
      `(define-public ,(car head)
	 ;; FIXME: why can't we use procedure->macro
	 ;; for a non-memoizing variant?
	 (procedure->memoizing-macro
	  (lambda (cmd env)
	    (apply (lambda ,(cdr head) ,@body) (cdr cmd)))))))

Any advice? Thanks.

Germán.

Re: Help to TeXmacs with Guile 2

[David Pirotte]

Hello Germán,

> (if (guile-a?)
>     (define-macro (define-public-macro head . body)
>       `(define-public ,(car head)
> 	 ;; FIXME: why can't we use procedure->macro
> 	 ;; for a non-memoizing variant?
> 	 (procedure->memoizing-macro
> 	  (lambda (cmd env)
> 	    (apply (lambda ,(cdr head) ,@body) (cdr cmd)))))))

For these guile version related code, I suggest something like this:

(cond-expand
  (guile-2
    ... ...)
  (else
    (define-macro (unless test . body)
      `(if (not ,test) (begin ,@body)))
      (export unless))))

Here is a real case example [which starts @ line 44]:

	http://git.savannah.gnu.org/cgit/guile-gnome.git/tree/glib/gnome/gobject/utils.scm

Cheers,
David

Re: Help to TeXmacs with Guile 2

[Germán Arias]

On 2014-06-01 11:54:13 -0600 David Pirotte <david@altosw.be> wrote:

> Hello Germán,
> 
>> (if (guile-a?)
>>      (define-macro (define-public-macro head . body)
>>        `(define-public ,(car head)
>> 	 ;; FIXME: why can't we use procedure->macro
>> 	 ;; for a non-memoizing variant?
>> 	 (procedure->memoizing-macro
>> 	  (lambda (cmd env)
>> 	    (apply (lambda ,(cdr head) ,@body) (cdr cmd)))))))
> 
> For these guile version related code, I suggest something like this:
> 
> (cond-expand
>   (guile-2
>     ... ...)
>   (else
>     (define-macro (unless test . body)
>       `(if (not ,test) (begin ,@body)))
>       (export unless))))
> 
> Here is a real case example [which starts @ line 44]:
> 
> 	http://git.savannah.gnu.org/cgit/guile-gnome.git/tree/glib/gnome/gobject/utils.scm
> 
> Cheers,
> David
> 
> 

Thanks for the answers. I solved this problem, although now I have other problems. I will try to solve them, if not I request again your help.

Germán.

Re: Help to TeXmacs with Guile 2

[Artyom Poptsov]

Hi German,

> I don't have experience with macros. But I get this error trying
> TeXmacs with Guile 2.x:

I think the problem is that you trying to define a macro in a context in
which definitions are not allowed.  Here what the Guile docs says:

"A ‘define-syntax’ form is valid anywhere a definition may appear: at
the top-level, or locally." [1]

"A ‘define’ form which appears inside the body of a ‘lambda’, ‘let’,
‘let*’, ‘letrec’, ‘letrec*’ or equivalent expression is called an
"internal definition".  [..] Internal definitions are only allowed at
the beginning of the body of an enclosing expression.  They may not be
mixed with other expressions." [2]

It means that you should define the macro either in the top level
context (outside any define's, let's etc) or at the beginning of a local
binding contruct like `let', `letrec' etc.

I hope this helps.

Thanks,

- Artyom

[1] https://www.gnu.org/software/guile/manual/html_node/Defining-Macros.html#Defining-Macros
[2] https://www.gnu.org/software/guile/manual/html_node/Internal-Definitions.html#Internal-Definitions

-- 
Artyom V. Poptsov <poptsov.artyom@gmail.com>
Home page: http://poptsov-artyom.narod.ru/