Having a concept extend/subtype a specific class?

Hello, I'm writing a DSL extending baseLanguage with MPS; I'm still new on MPS so there is some things about the type system that I don't really understand yet.

Currently, I'm stucked on this: in my language I have the concept "Agent", which extends ClassConcept and which is converted to base language "Class<? extends Agent>". Basically, I want my users to write "agent X { ... }" in the DSL and at the end (with generators) I want it to be converted in "class X extends Agent { ... }". So far, this works.

I also have an external library which provides methods which takes as parameters objects which are either of type "Agent" or of type "Class<? extends Agent>". For instance, I will talk about a method "spawn(Class<? extends Agent> agentClass)".

If I declare "class X extends Agent { ... }", later in the code I'm able to write "spawn(X.class)". But if I declare "agent X", and I call "spawn(X.class)" then I get the error "Error: X is not a subtype of Agent". And I want to find a way to suppress this error.

I guess it's something really simple related to the type system, but I did'nt find how to do it.

Thanks for any help.

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Two things:

concept behavior Agent {                                                                                                                                                                               

constructor {
<no statements>

public virtual boolean isDescendant(node<Classifier> nodeToCompare)
overrides Classifier.isDescendant {
if (nodeToCompare.is(AgentClass)) { return true; }



subtyping rule Agent_subtypeof_Thread {                                                                                            
weak = false
applicable for concept = ClassifierType as classifierType

supertypes {
nlist<> result = new nlist<>;
if (classifierType.classifier.isInstanceOf(Agent)) {
return result;
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Thanks a lot, it works perfectly :)


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