[Python-ideas] An Everything singleton

[Steven D'Aprano]

On Tue, Feb 18, 2014 at 09:07:07PM +0200, Serhiy Storchaka wrote:
> This crazy idea is inspired by a discussing in Python-Dev which should 
> be here.
> 
> Currently we have a None singleton which representing nothing and raises 
> an exception in almost all operations (except equality, etc). What about 
> introducing its antonym, an Everything singleton (the name is 
> discussable), which newer raises an exception in any operation, but 
> returns consistent value?
> 
> >>> Everything + 2
> 2

Here, your Everything value acts like the Null Object pattern.

> >>> Everything < 3
> True

Here, your Everything value acts like a Smallest object. But if you then 
do Everything > 5, presumably you would want it to return True, so it 
also acts like a Biggest object.

Why have Everything < 3 return True? Why not False?

> >>> Everything * 'foo'
> 'foo'

Here, your Everything object acts like an Identity object. But earlier 
you had it acting like a Null object. How does the Everything object 
decide whether it should behave as Null or Identity for a certain 
operation? E.g. should 23**Everything return 1 or 23?

    23 == Everything == 42

will presumably return True.

What should these things do?

    some_dict.pop(Everything)  # Is this the same as some_dict.clear()?
    Everything & 42
    '+'.join(['a', 'b', Everything, 'c'])



I don't think this idea is either useful or self-consistent.



-- 
Steven