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Re: emacs and guile (Re: ehelp woes, or why I hate a module that I love


From: Marius Vollmer
Subject: Re: emacs and guile (Re: ehelp woes, or why I hate a module that I love so much)
Date: 20 Jul 2002 14:00:17 +0200
User-agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2

Richard Stallman <address@hidden> writes:

>     For additional fields, there is 'make-object-property'.  This function
>     returns a procedure-with-setter so that can you do, for example,
> 
>       (define symbol-foo (make-object-property))
> 
>       (symbol-foo 'x)
>       => #f
>       (set! (symbol-foo 'x) 123)
>       (symbol-foo 'x)
>       => 123
> 
>     make-object-property is implemented with a hash table of alists.
> 
> If Emacs needs any more than the function and the plist, 
> we should provide additional slots in the symbol itself,
> or a facility to for an application that uses Guile to request
> more of them.

Ok.  However, we have only two sizes of Scheme cells: 2 words and 4
words.  (Non-immediate objects are implemented by pointers to such a
cell.)  We can not easily add more slots to the cell of a symbol.
Thus, we will lose some performance for additional slots, as compared
to the function slot, say.



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