[erlang-questions] Best way to test if empty dict/set/etc.?

[Vance Shipley]

On 05/31/2013 09:03 AM, Vance Shipley wrote:
}  With gb_trees and gb_sets size/1 is O(1).  These opaque data structures
}  happen to be tuples where the first element is the size:
   ^^^^^^^^^^^^

On Fri, May 31, 2013 at 09:25:48AM +0200, Kostis Sagonas wrote:
}  I am afraid this statement (relying on the structure being a tuple)
}  breaks the opacity of the data structure.  So does your call to
}  element/2 below.
  
Indeed, I made that point.  My answer was in the first sentence.  
The rest of my post was unecessary editorializing.

}  Since I've also stumbled across something analogous in the past,
}  IMO the proper solution is to extend the API of these opaque data
}  structures (these modules) by providing is_empty/1 functions for
}  them.
  
Only if they are bifs will it help with my (unsolicited) example.
Sometimes it's just too compelling to resist taking advantage
of knowing how the opaque data structures work.

-- 
	-Vance