typo in guile doc?

typo in guile doc?

[Chengqi Song]

http://www.gnu.org/software/guile/manual/html_node/Garbage-Collection.html#Garbage-Collection
4th paragraph of "4.3.2 Garbage Collection":

"You do this when writing a SMOB mark function, for example (see Garbage Collecting Smobs). By calling this function, the garbage collector learns about all references that your SMOB has to other SCM values."

what is "has to other SCM values"? is it a typo?

thanks
lars

Re: typo in guile doc?

[Thien-Thi Nguyen]

() Chengqi Song <songcq@gmail.com>
() Sun, 27 Dec 2009 07:22:50 +0800

   "By calling this function, the garbage collector learns
   about all references that your SMOB has to other SCM values."

   what is "has to other SCM values"? is it a typo?

Perhaps that object contains (points to, references) other
sub-objects.  The SMOB's mark function must call (back to) Guile's
mark function for those sub-objects.  In this way the collector learns.
If the mark function fails to do that, the collector remains ignorant.

thi

Re: typo in guile doc?

[Neil Jerram]

Thien-Thi Nguyen <ttn@gnuvola.org> writes:

> () Chengqi Song <songcq@gmail.com>
> () Sun, 27 Dec 2009 07:22:50 +0800
>
>    "By calling this function, the garbage collector learns
>    about all references that your SMOB has to other SCM values."
>
>    what is "has to other SCM values"? is it a typo?
>
> Perhaps that object contains (points to, references) other
> sub-objects.  The SMOB's mark function must call (back to) Guile's
> mark function for those sub-objects.  In this way the collector learns.
> If the mark function fails to do that, the collector remains ignorant.

We could rewrite this as:

>    "By calling this function, the garbage collector learns
>    about the other SCM values (if any) that your SMOB refers to."

Would that be clearer?

Also please note that this is different in Guile 1.9.x.  (In summary,
the mark function isn't needed any more.)  If you're writing something
new, you may want to consider targeting Guile 1.9.x instead of 1.8.x.

Regards,
        Neil