Eliminating duplicate code in tapset files

[Mike Mason]

Suppose I have a tapset with many probes and most of the variables exposed by these probes are the same.  Rather than duplicating the same code over and over, I'd like to define the variables once and reference that definition in each probe, similar to a macro.  I envision something like below (details TBD).  Is there some way to accomplish this now in SystemTap?  If not, how do others feel about adding this capability?

Mike

macro VFS_COMMON
{
        file = $file
        count = $count
        pos = $pos
        buf = $buf
        dev = __file_dev($file)
        devname = __find_bdevname(dev, __file_bdev($file))
        ino = __file_ino($file)
        filename = __file_filename($file)
}

probe vfs.read = kernel.function ("vfs_read")
{
	%VFS_COMMON
        size = count
}

probe vfs.read.return = kernel.function ("vfs_read").return
{
	%VFS_COMMON
        size = $return
}

probe vfs.write = kernel.function ("vfs_write")
{
	%VFS_COMMON
        size = count
}

probe vfs.write.return = kernel.function ("vfs_write").return
{
	%VFS_COMMON
        size = $return
}