Merged relational+boolean operators?

[Daynvheur]

Hi, when checking for out of bounds values, I often repeat the same var name over, and over.
Example: if (j < dateStart || j > dateEnd) throw new NotImplementedException();

I'd like to have this variable name j not repeated while still checked for both boundaries.

As I didn't found a way to achieve it in one operation, I propose the implementation of merged comparison operators (not every may have real use cases):

• <||> 'inf left or sup right', ex: j <||> (dateStart, dateEnd)
• <||= 'inf left or equ right'
• <||=> 'inf left or sup or equ right'
• =||> 'equ left or sup right'
• =||= 'equ left or equ right', ex: if (j =||= (dateStart, dateEnd)) ; is similar with switch expression: if (j switch { dateStart => true, dateEnd => true, _ => false }) ;
• =||=> 'equ left or sup or equ right'
• <=||> 'inf or equ left or sup right'
• <=||= 'inf or equ left or equ right'
• <=||=> 'inf or equ left or sup or equ right'
  (Same for && operator instead of ||, and optionally allowing != comparisons.)

Would you find those usefull? Any thoughts about this?

[alrz]

See #4108

[Daynvheur]

Ternary comparison operators looks interesting (I've alreay read this proposal a while ago, couldn't find it when opening here), I would comment on there, as there is a slight difference in the treatment of A<C>B vs A<||> (C,B).

[Richiban]

Since we have relational patterns now, you should be able to write this:

if (j is < dateStart or > dateEnd) throw new NotImplementedException();

if (j is x or y or z or < 1000) throw new NotImplementedException();

But unfortunately they don't allow comparisons with variables, only constants. I'd much rather we augmented this existing syntax to allow non-constant comparisons; I think that's a lot better than introducing new operators.

[Daynvheur]

Relational patterns are something I'd like to use more, if only it wasn't specifically for constants!