After the fix, the result above is correctly rendered as Sig.

I updated VBehavior::convertToDescription so it uses TransitionUsage operations to get the trigger action, guard expression and effect action. I also updated triggerToText so it is similar to the corresponding code in addAcceptActionUsage, accounting for trigger actions with declared names and receivers. The model

package ST6RI_867 {
    attribute def Sig;
    
    state s0 {
    	state s01;
    	then done;
    }
    state s1 {
    	state s11;
    	accept Sig then done;
    }
    state s2 {
    	state s21;
    	accept s : Sig then done;
    }
    state s3 {
    	state s31;
    	accept Sig via this then done;
    }
}

is now visualized as

Please review and let me know if this is acceptable.

@seidewitz, thank you! That is great, but I found two issues on AcctionActionUsage rendering. So far, we use : to show type name even if it does not have a default name (payload). So for example:

attribute def Sig;
action a0 {
    accept : Sig;
}

is rendered as

I want to make it consistent and should we eliminate : if it does not have a default name? (Note that the textual syntax allow both. Both accept :Sig and action Sig are valid syntax and I want to make the notations consistent.)

Also I found if there is no declared name, a proper effective name is not rendered properly:

	attribute def Sig;
	attribute ss : Sig;
    state s1 {
    	state s11;
    	accept :>> ss then done;
    }

I can fix these if we always omit or render : in the case we do not have a proper payload name. appendNameType() is designed to support such case and I want to apply it to trigger's AcceptActionUsage as well.

I can fix these if we always omit or render : in the case we do not have a proper payload name. appendNameType() is designed to support such case and I want to apply it to trigger's AcceptActionUsage as well.

I think it is better to always omit the : if there is not a proper payload name.

Thank you. I updated based on your comment:

package ST6RI867 {
	attribute def Sig;
	
	action a0 {
	    accept Sig;
	    accept s:Sig;
	}
	
	    
    state s0 {
    	state s01;
    	then done;
    }
    
    state s1 {
    	state s11;
    	accept Sig then done;
    }


    state s2 {
    	state s21;
    	accept s : Sig then done;
    }
    
    state s3 {
    	state s31;
    	accept Sig via this then done;
    }
    
    
    attribute ss : Sig;
	state s4 {
    	state s41;
    	accept :>> ss then done;
    }
    state s5 {
    	state s51;
    	accept :>> ss : Sig then done;
    }
   
}

is rendered as:

Note that we do not show Sig in state s4 example because we do not render inherited type name by default.