TreeModelFilter modify func

[Kevin Ryde <user42 zip com au>]

Is there a trick to giving back the value in a set_modify_func function
in a TreeModelFilter?  I wondered if it was/is/meant-to-be a return
value.  Maybe as per below?

--- GtkTreeModelFilter.t	18 Jun 2006 23:39:53 +1000	1.8
+++ GtkTreeModelFilter.t	03 May 2008 07:40:14 +1000	
@@ -1,7 +1,7 @@
 #!/usr/bin/perl -w
 use strict;
 use Gtk2::TestHelper
-  tests => 24,
+  tests => 26,
   noinit => 1,
   at_least_version => [2, 4, 0, "GtkTreeModelFilter is new in 2.4"];
 
@@ -53,6 +53,27 @@
 $filter -> refilter();
 $filter -> clear_cache();
 
+$filter = Gtk2::TreeModelFilter -> new($list, undef);
+$filter -> set_modify_func
+  (["Glib::Int", "Glib::String"],
+   sub { my ($filter, $iter, $col, $userdata) = @_;
+         my $path = $filter->get_path ($iter);
+         if ($col == 0) {
+           my ($pos) = $path->get_indices;
+           return $pos * 100 + $col;
+         }
+         if ($col == 1) {
+           return "column $col userdata $userdata path "
+             . $path->to_string;
+         }
+       }, 12345);
+
+is ($filter->get_value($filter->iter_nth_child(undef,2), 0),
+    200);
+is ($filter->get_value($filter->get_iter_first, 1),
+    'column 1 userdata 12345 path 0');
+
+
 $filter = Gtk2::TreeModelFilter -> new($list, Gtk2::TreePath -> new_from_string("1"));
 isa_ok($filter, "Gtk2::TreeModelFilter");
 

--- GtkTreeModelFilter.xs	10 Jan 2008 09:51:09 +1100	1.14
+++ GtkTreeModelFilter.xs	03 May 2008 09:17:13 +1000	
@@ -55,8 +55,7 @@
                                         gpointer      data)
 {
 	GPerlCallback * callback = (GPerlCallback*) data;
-	SV * sv = sv_2mortal (gperl_sv_from_value (value));
-	gperl_callback_invoke (callback, NULL, model, iter, sv, column);
+	gperl_callback_invoke (callback, value, model, iter, column);
 }
 
 MODULE = Gtk2::TreeModelFilter	PACKAGE = Gtk2::TreeModelFilter	PREFIX = gtk_tree_model_filter_
@@ -87,6 +86,17 @@
 			 callback, (GtkDestroyNotify)gperl_callback_destroy);
 
  ## void gtk_tree_model_filter_set_modify_func (GtkTreeModelFilter *filter, gint n_columns, GType *types, GtkTreeModelFilterModifyFunc func, gpointer data, GtkDestroyNotify destroy);
+=for apidoc
+=for arg types (scalar) type name string for one column, or an arrayref of type names for multiple columns
+func is called as
+
+    sub myfunc {
+      my ($filter, $iter, $column_num, $data) = @_;
+      ...
+
+and should return the value from the filtered model that iter row and
+column number.
+=cut
 void gtk_tree_model_filter_set_modify_func (GtkTreeModelFilter *filter, SV * types, SV * func=NULL, SV * data=NULL);
     PREINIT:
 	GType * real_types = NULL;
@@ -119,10 +129,9 @@
 		GType param_types[4];
 		param_types[0] = GTK_TYPE_TREE_MODEL;
 		param_types[1] = GTK_TYPE_TREE_ITER;
-		param_types[2] = GPERL_TYPE_SV;
-		param_types[3] = G_TYPE_INT;
-		callback = gperl_callback_new (func, data, 4, param_types,
-		                               G_TYPE_NONE);
+		param_types[2] = G_TYPE_INT;
+		callback = gperl_callback_new (func, data, 3, param_types,
+		                               G_TYPE_VALUE);
 		gtk_tree_model_filter_set_modify_func
 				(filter, n_columns, real_types,
 				 gtk2perl_tree_model_filter_modify_func,