TYPEMAP
Edge *		O_OBJECT
Graph *		O_OBJECT
Node *		O_OBJECT


OUTPUT
# The Perl object is blessed into 'CLASS', which should be a
# char* having the name of the package for the blessing.
O_OBJECT
    sv_setref_pv( $arg,
	"Search::ContextGraph::${(my $foo = $type) =~ s/ .*//g; \$foo}", 
	(void*)$var );

INPUT
O_OBJECT
    if( sv_isobject($arg) && (SvTYPE(SvRV($arg)) == SVt_PVMG) )
	$var = ($type)SvIV((SV*)SvRV( $arg ));
    else {
	warn( \"${Package}::$func_name() -- $var is not a blessed SV reference\" );
	XSRETURN_UNDEF;
    }