[plt-scheme] writing structures

You may also want to check out the print-convert function in the
pconvert.ss library.

Robby

At Mon, 20 Jan 2003 12:56:11 -0500, "Richard C. Cobbe" wrote:
>   For list-related administrative tasks:
>   http://list.cs.brown.edu/mailman/listinfo/plt-scheme
> 
> Lo, on Monday, January 20, Pedro Pinto did write:
> 
> > Hi there,
> > 
> > I am trying to serialize a structure I created using:
> > 
> > (define-struct my-struct (field1 field2 field3))
> > (define s (make-my-struct 1 2 3))
> > 
> > Ideally I would like to simply use:
> > 
> > (write s port)
> > 
> > and
> > 
> > (define s (read port))
> > 
> > Is something like this possible? 
> 
> About halfway, yes.
> 
> If you have a sufficiently powerful inspector (see section 4.6 of the
> MzScheme manual), then you can do something like
> 
> (write (struct->vector s) port)
> 
> Reading is a bit less straightforward; you'll have to do something like
> 
> (define s (parse-foo (read port)))
> 
> where parse-foo is a function that takes a vector as its argument and
> parses it to an instance of the structure.  Note, by the way, that the
> first element in this vector will be a symbol naming the kind of
> structure.  You will likely find the match library very helpful in
> writing parse-foo.
> 
> For the example above:
> 
> (define parse-foo
>   (match-lambda
>     [#('struct:my-struct field1 field2 field3) 
>      (make-my-struct field1 field2 field3)]))
> 
> Richard