Racket code generation - racket

Question

When you want to use Racket's D-Bus binding (https://docs.racket-lang.org/dbus/index.html) you must write definition of interface by hand. D-bus protocol is defined by .xml file and basically gives you method name with arguments and their types definition. Type definitions are coded so y = byte, s = string etc. Xml file example:
<node>
<interface name="com.test.Callable">
<method name="TestMethod">
<arg name="data_in" type="sa(yyd)" direction="in" /> ;;
<arg name="data_in2" type="y" direction="in" /> ;;
<arg name="data_out" type="i" direction="out" />
</method>
</interface></node>
In Racket's dbus must all type fields of arg elements with direction=in be joined and produced code like this:
(define-dbus-interface dbus-interface<%> "com.test.Callable"
(TestMethod "sa(yyd)y") ;; pay attention to this line
)
Now you can finally implement this interface in your own class as you wish and start sending some messages through D-bus.
Problem is, that you can have several methods with nontrivial arguments and you can make easily mistake, so I wanted to create a code generator, that will take name of an .xml file and produces definition of interface (define-dbus-interface) automatically.
My progress so far can be found here: https://gitlab.com/Ondra009/dbus-interface It is only one file about 90 lines long.
I want to make this call:
(parse-xml/file "org.freedesktop.Avahi.ServiceBrowser.xml")
on my testing file and I am expecting to receive definition of interface back. So far, I was able to parse file and generate, what I believe, is correct syntax of (define-dbus-interface ...) method call.
I think this should be last step but here I got stuck. I am not able to see definition of interface from top level. Listing of error I am getting:
../../../.racket/6.10.1/pkgs/dbus/dbus/main.rkt:228:11: define: not allowed in an expression context in: (define org.freedesktop.DBus.Introspectable<%>/c (class/c (Introspect (->m any)) (TestMethod (->m string? (listof (list/c (integer-in 0 255) (integer-in 0 255) real?)) (integer-in 0 255) (cons/c (integer-in 0 255) (integer-in 0 255)) any))))
This is obviously expansion done by dbus package itself as my generated code look like code listing starting with (define-dbus-inteface ...).
So my question here could be:
Can I even use this as C-macro like system, in a manner that call is completelly replaced by another definition or do I have to bind generated code to some identifier? (or list of idetifiers in case more interface definitions in one file.
If so, how can I achieve it?