Re: [Chicken-users] Adding a free slot to Chicken symbols

[felix winkelmann]

On 4/1/06, John Cowan <address@hidden> wrote:
> This is a feature request for Chicken.  It's hopefully very simple to
> implement, and it will be extremely useful for me, but it's a fairly deep
> change to the system, and it will have impact on people who don't use it.
>
> I'd like to have an extra slot provided with each symbol that can contain
> any Chicken object.  Two primitive procedures (I propose symbol-slot
> and symbol-slot-set!) will provide read and write access to the slot.
> This will be very useful for implementing true property lists in my Lisp
> 1.5 emulator and for other purposes in my Joy interpreter.
>

Attached is a patch that _appears_ to work. It's against the current darcs
HEAD and will definitely break when loading extensions or interfacing
with code compiled with a different chicken.
Adding an extra slot to symbols would be pretty handy, and would make
it easy to implement different Lisps in chicken, but I wonder how much code
depends on C_SIZEOF_SYMBOL being 3....

Anyway, give the patch a try, please.


cheers,
felix

extraslot.diff
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