Beginner question: where is defstruct?

Beginner question: where is defstruct?

[Josef Wolf]

Hello,

I am about to learn scheme by working through some tutorials.  My first
attempt is http://www.ccs.neu.edu/home/dorai/t-y-scheme/t-y-scheme.html,
which is suggested from the schemers.org pages.

Now I would like to use structures as described in
http://www.ccs.neu.edu/home/dorai/t-y-scheme/t-y-scheme-Z-H-11.html
but all I get from guile is

   ERROR: Unbound variable: defstruct

In guile's info page, all I can find is chapter 22.5, but this seems
to describe something much more general than what defstruct would do.

BTW: this is guile 1.6.7 as it comes with suse linux 10.0


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Re: Beginner question: where is defstruct?

[Ludovic Courtès]

Hi,

Josef Wolf <jw@raven.inka.de> writes:

> In guile's info page, all I can find is chapter 22.5, but this seems
> to describe something much more general than what defstruct would do.

`defstruct' as described in this document is something specific to some
Scheme implementation.  The chapter you saw in Guile's manual is another
non-portable way to define structures, in Guile this time.

The most portable way to define structures is to use SRFI-9:

  http://srfi.schemers.org/srfi-9/srfi-9.html

It is available in Guile using "(use-modules (srfi srfi-9))" or
"(require-extension (srfi 9))" (the latter being the portable way to get
the portable "structures"  :-)).

Hope this helps,
Ludovic.



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Re: Beginner question: where is defstruct?

[Josef Wolf]

On Wed, Oct 10, 2007 at 06:21:25PM +0200, Ludovic Courtès wrote:
> Josef Wolf <jw@raven.inka.de> writes:
> > In guile's info page, all I can find is chapter 22.5, but this seems
> > to describe something much more general than what defstruct would do.
> `defstruct' as described in this document is something specific to some
> Scheme implementation.  The chapter you saw in Guile's manual is another
> non-portable way to define structures, in Guile this time.
> 
> The most portable way to define structures is to use SRFI-9:
> 
>   http://srfi.schemers.org/srfi-9/srfi-9.html
> 
> It is available in Guile using "(use-modules (srfi srfi-9))" or
> "(require-extension (srfi 9))" (the latter being the portable way to get
> the portable "structures"  :-)).

Thanks for the explanation, Ludovic!  I'll go and try to read/understand
srfi-9.

BTW: Why do people teach newbies non-portable things in their tutorials?


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Re: Beginner question: where is defstruct?

[Ludovic Courtès]

Hi,

Josef Wolf <jw@raven.inka.de> writes:

> BTW: Why do people teach newbies non-portable things in their tutorials?

Because there aren't always portable ways to do things, or because the
portable API appeared after the implementation's own API.

Thanks,
Ludovic.


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Re: Beginner question: where is defstruct?

[dsmich]

---- Josef Wolf <jw@raven.inka.de> wrote: 
> Thanks for the explanation, Ludovic!  I'll go and try to read/understand
> srfi-9.
> 
> BTW: Why do people teach newbies non-portable things in their tutorials?

In this case, I think that tutorial predates the srfi.

-Dale



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