On 29.09.2015 02:38, Terry Reedy wrote:
On 9/28/2015 5:48 PM, Luciano Ramalho wrote:
Glyph tweeted yesterday that everyone should watch the "Nothing is Something" 35' talk by Sandi Metz at RailsConf 2015. It's great and, in a way, relevant to this discussion.
I understood Metz as advocation avoidig the nil (None) problem by giving every class an 'active nothing' that has the methods of the class. We do that for most builtin classes -- 0, (), {}, etc. She also used the identity function with a particular signature in various roles.
I might stress here that nobody said there's a single "active nothing". There are far more "special case objects" (as Robert C. Martin calls it) than 0, (), {}, etc. I fear, however, the stdlib cannot account for every special case object possible. Without None available in the first place, users would be forced to create their domain-specific special case objects. None being available though, people need to be taught to avoid it, which btw. she did a really good job of. Best, Sven