code: public Element getGlobalVariable(String name) {
  		GlobalVariable gvar = globalVariables.get(name);
  		return (gvar != null) ? gvar.getValue() : null;
  	}
docs: Return the Element which corresponds to the given variable name without
  duplicating the value. This is useful when dealing with SELF or with
  variables in a context where it is known that the value won't be
  modified.