%del AClass %for %search ("", "Class") $ AClass never becomes %c here %endfor
%for %all %search ("", "Class") $ AClass is iterated here because %for has the optional %all modifier %endfor
%undel AClass %for %search ("", "Class") $ AClass is iterated here because it has been %undeleted %endfor
%del <object expression> prevents the target object to be subsequently iterated by %for loops. %del marks the object in such a way so that %for automatically ignores it. %undel restores the object back to its enumerable status.
%for ignores the %deleted objects unless the optional %all modifier is used in the %for construct.