Re: Cooperating on .defs API specifications

[Andreas Rottmann <a rottmann gmx at>]

James Henstridge <james daa com au> writes:

> On 31/03/2004 3:52 AM, Andreas Rottmann wrote:
>
>>Why not have .defs files, and generate the binary info from them? The
>>.defs files are already there, and they contain more information than
>>the headers do (well, comment parsing might change that, but you could
>>create comments from the .defs files :)). Just an idea...
>>
> For simple cases, the defs files contain enough information.  For the
> more complex cases, they lack some information that would be needed
> for full introspection.  Some examples are:
>
>     * what types do (GList *) arguments and return values hold?  How
>       should a binding release a (GList *) return value? (in various
>       parts of GTK and Gnome, the answer is "free all members then the
>       list", "free the list" and "do nothing")
>
In guile-gobject, we use "Glist*-of-FOO" and caller-owns-return to
solve this (well the return value problem only partially). Examples:

(define-method set_popdown_strings
  (of-object "GtkCombo")
  (c-name "gtk_combo_set_popdown_strings")
  (return-type "none")
  (parameters
    '("GList*-of-gchar*" "strings")
  )
)

(define-method copy
  (of-object "GtkIconSet")
  (c-name "gtk_icon_set_copy")
  (return-type "GtkIconSet*")
  (caller-owns-return #t)
)

>     * Some functions take an array and a length arguments.  It would be
>       good to link these together (for most languages, we should be able
>       to omit the length arguments, since their list/array types know
>       their length).
>
Indeed. We could "invent" a new parameter type to describe this.

>     * Is an (int *) argument an array of ints being passed in, an array
>       of ints that will be modified (inout), or a pointer to a single
>       int being used as an out argument?
>
One could add specifiers to those value's type strings,
e.g. int*-in-out.

Andy
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