GNU bug report logs - #11764
Missing C API doc for accessing unknown number of values

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: David Kastrup <dak <at> gnu.org>
To: bug-guile <at> gnu.org
Subject: Missing C API doc for accessing unknown number of values
Date: Fri, 22 Jun 2012 17:17:12 +0200

<URL:http://www.gnu.org/software/guile/manual/html_node/Multiple-Values.html#Multiple-Values>

provides scm_c_value_ref for accessing a particular value from a values
object.  There is no documented way for figuring out how many values
there are.  There is no documented way for getting the complete list of
values in an object (Guile itself uses scm_struct_ref (value,SCM_INUM0)).

While there is a macro VALUESP for figuring out whether an SCM is a
values object, it is not documented either.

-- 
David Kastrup

Message #10 received at 11764-done <at> debbugs.gnu.org (full text, mbox):

From: Andy Wingo <wingo <at> pobox.com>
To: David Kastrup <dak <at> gnu.org>
Cc: 11764-done <at> debbugs.gnu.org
Subject: Re: bug#11764: Missing C API doc for accessing unknown number of
	values
Date: Wed, 04 Jul 2012 17:52:37 +0200

Hi David,

Thanks for the report.  I've added this somewhat strangely named
function:

 -- C Function: size_t scm_c_nvalues (SCM obj)
     If OBJ is a multiple-values object, returns the number of values
     it contains.  Otherwise returns 1.

Incidentally there is also this new one:

 -- C Function: SCM scm_c_values (SCM *base, size_t n)
     `scm_c_values' is an alternative to `scm_values'.  It creates a
     new values object, and copies into it the N values starting from
     BASE.

     Currently this creates a list and passes it to `scm_values', but we
     expect that in the future we will be able to use more a efficient
     representation.

Suggestions for different names are welcome.

Regards,

Andy
-- 
http://wingolog.org/

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