@namespace(uri="argumentmodel", prefix="argumentmodel")
@gmf(foo="bar")
package argumentmodel;

@gmf.diagram(onefile="false")
class ArgumentModel {
   val Claim[*] claims;
   val Assumption[*] assumptions;
}

@gmf.node(label="name")
class Claim {
   attr String name;
   attr String description;
   @gmf.link(incoming="true")
   val ArgumentStrategy[*] ConnectArg;
}

@gmf.node(label="name",phantom="true")
class ArgumentStrategy {
   attr String description;
   attr String name;
   @gmf.link(incoming="true")
   ref Assumption [*] assumptions;  
}
@gmf.node(label="name")
class Assumption {
   attr String description;
   attr String name;

}

var tool = GmfTool!CreationTool.all.selectOne(t|t.title = 'assumptions');
var nodeMapping = GmfMap!NodeMapping.all.selectOne(nm|nm.tool = tool);

delete tool;
nodeMapping.unset('tool');
nodeMapping.tool.println();

operation Any unset(feature:String) {
var sf = self.eClass().eAllStructuralFeatures.
selectOne(sf|sf.name = feature);
self.eUnset(sf);
}