problems evaluating code depending on version

problems evaluating code depending on version

[Stefan Israelsson Tampe]

[-- Attachment #1: Type: text/plain, Size: 798 bytes --]

hi,

I'm trying to use this as a way to defined different versions of the code
depending on the
guile-version. So here it is,



(eval-when (compile load eval)
  (define (ver)
    (let ((v (version)))
      (cond
       ((string-match "^2.0" v)
        'v2.0)
       ((string-match "^2.1" v)
        'v2.1)
       (else #f)))))

(define-syntax guile-stuff
  (lambda (x)
    (syntax-case x ()
      (_
       (let ((q (ver)))
         (cond
          ((eq? q 'v2.0)
           #'(begin 1))
          ((eq? q 'v2.1)
           #'(begin
               (define-syntax-rule (fluid-let-syntax . l)
                 (syntax-parametrize . l))
               (export fluid-let-syntax)))
          (else (error "not supported version"))))))))

(guile-stuff)

This does not work in master (v2.1) why?
/Stefan

[-- Attachment #2: Type: text/html, Size: 979 bytes --]

Re: problems evaluating code depending on version

[Andy Wingo]

On Wed 16 May 2012 23:32, Stefan Israelsson Tampe <stefan.itampe@gmail.com> writes:

> (define-syntax guile-stuff
>   (lambda (x)
>     (syntax-case x ()
>       (_
>        (let ((q (ver)))
>          (cond
>           ((eq? q 'v2.0)
>            #'(begin 1))
>           ((eq? q 'v2.1)
>            #'(begin
>                (define-syntax-rule (fluid-let-syntax . l)
>                  (syntax-parametrize . l))
>                (export fluid-let-syntax)))
>           (else (error "not supported version"))))))))

Here the macro introduces a new identifier, fluid-let-syntax.  But its
context is not that of the (guile-stuff) expression.  If you did
(datum->syntax 'fluid-let-syntax x) that might work.

In general cond-expand is better.  I just added a guile-2.2 feature on
master.  Use that instead.

But in this case, better to just change both versions to use
syntax-parameterize :)

Andy
-- 
http://wingolog.org/

Re: problems evaluating code depending on version

[Stefan Israelsson Tampe]

[-- Attachment #1: Type: text/plain, Size: 1364 bytes --]

I tried cond-expand, just to see if it worked and no
the export clause does not fall through and the symbols are not exported.

I can fix this as you say by using the new interface syntax-parameter
interface
but I'm curious how to be ably to conditionally export symbols depending on
the
guile-version!

/Stefan

On Thu, May 17, 2012 at 10:20 AM, Andy Wingo <wingo@pobox.com> wrote:

> On Wed 16 May 2012 23:32, Stefan Israelsson Tampe <stefan.itampe@gmail.com>
> writes:
>
> > (define-syntax guile-stuff
> >   (lambda (x)
> >     (syntax-case x ()
> >       (_
> >        (let ((q (ver)))
> >          (cond
> >           ((eq? q 'v2.0)
> >            #'(begin 1))
> >           ((eq? q 'v2.1)
> >            #'(begin
> >                (define-syntax-rule (fluid-let-syntax . l)
> >                  (syntax-parametrize . l))
> >                (export fluid-let-syntax)))
> >           (else (error "not supported version"))))))))
>
> Here the macro introduces a new identifier, fluid-let-syntax.  But its
> context is not that of the (guile-stuff) expression.  If you did
> (datum->syntax 'fluid-let-syntax x) that might work.
>
> In general cond-expand is better.  I just added a guile-2.2 feature on
> master.  Use that instead.
>
> But in this case, better to just change both versions to use
> syntax-parameterize :)
>
> Andy
> --
> http://wingolog.org/
>

[-- Attachment #2: Type: text/html, Size: 1982 bytes --]

Re: problems evaluating code depending on version

[Andy Wingo]

On Thu 17 May 2012 14:47, Stefan Israelsson Tampe <stefan.itampe@gmail.com> writes:

> I tried cond-expand, just to see if it worked and no
> the export clause does not fall through and the symbols are not exported.
>
> I can fix this as you say by using the new interface syntax-parameter interface
> but I'm curious how to be ably to conditionally export symbols depending on the
> guile-version!

(cond-expand
  (not guile-2.2
   (define-syntax-rule (fluid-let-syntax . l)
     (syntax-parameterize . l)))
  (else #t))

At the top level, not wrapped in (guile-stuff) :)

Andy
-- 
http://wingolog.org/

Re: problems evaluating code depending on version

[Stefan Israelsson Tampe]

[-- Attachment #1: Type: text/plain, Size: 984 bytes --]

Your version works but I would like to export as well in the cond-expand
e.g.

(cond-expand
 (guile-2.2
  (define-syntax-rule (fluid-let-syntax . l)
    (syntax-parametrize . l))
  (export fluid-let-syntax))

 (guile-2)

 (else (error "not supported version")))

/Stefan
On Thu, May 17, 2012 at 3:25 PM, Andy Wingo <wingo@pobox.com> wrote:

> On Thu 17 May 2012 14:47, Stefan Israelsson Tampe <stefan.itampe@gmail.com>
> writes:
>
> > I tried cond-expand, just to see if it worked and no
> > the export clause does not fall through and the symbols are not exported.
> >
> > I can fix this as you say by using the new interface syntax-parameter
> interface
> > but I'm curious how to be ably to conditionally export symbols depending
> on the
> > guile-version!
>
> (cond-expand
>  (not guile-2.2
>   (define-syntax-rule (fluid-let-syntax . l)
>     (syntax-parameterize . l)))
>  (else #t))
>
> At the top level, not wrapped in (guile-stuff) :)
>
> Andy
> --
> http://wingolog.org/
>

[-- Attachment #2: Type: text/html, Size: 1538 bytes --]