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Check eContainer for equality [message #800044]

Thu, 16 February 2012 16:13

Alex G

Messages: 96
Registered: January 2012

Member

Hi @all!

I want to traverse my AST from my DSL for scoping reasons. I have a node somewhere and want to go up (in direction to the root) to some (grand)parent. I know the type of the (grand)parent. Since I make these calls more often, I have a generic function in order to search for the parent (in XTend):

def getParentOfType(EObject obj, Class clazz) {
   var parent = obj;
   while(!parent.eClass.instanceClass.equals(clazz))
        parent = parent.eContainer
   parent
}

Surely I could also call something like and work on nodes

val parent = NodeModelUtils::getNode(obj).semanticElement

The question is: Is there an easier way to check eContainers for type equality with a generic eClass? Or is the method above the "most" generic and short one?

The problem is that if call this function I have to write something like:

val x = some_eObject.getParentOfType(typeof(some_eClass)) as some_eClass

and this is not nice in my opinion.

Furthermore the function above returns null if no parent eContainer along the tree to the root is found. Since I use this function in local scope methods, I would need to return therefore not null but IScope::NULLSCOPE. Is there a way to return the NULLSCOPE by default, if null would have been returned?

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