VB.NET/Language

Although I see where you are going with this, I still feel that I'd prefer to write it "long hand" if for nothing more than clarity sake. Once we have too many symbols floating around, the intent of what the developer is trying to do (IMO) seems to get lost in the noise.

Dim sign = "Positive"
Select Case value
   Case > 0: sign="Positive"
   Case = 0: sign="Zero"
   Case < 0: sign="Negative" 
   Case Else: Throw New Exception("Should be impossible to get here in my analysis.")
 End Select

or

Dim sign="Zero"
Select Case value
     Case > 0: sign = "Positive"
     Case < 0: sign = "Negative"
     Case Else ' Already determined
 End Select

To me the second example (above) is easier to read making it easier to maintain. I also (based on looking at this very little) feel that it is easier to maintain/expand/adjust later. This, of course, could just be a case of me being used to doing it this way; so I'll have to admit that may be influencing my take on this.

As for the := there does seem to be something that could create a bit of a parsing issue since a : already means something; I'm sure that could be dealt with... but it is something that would have to be considered.

I suppose I just feel that having an "inline" Select Case is trying to force something into a position where there may be a better option. I recall from "ancient" history that there used to be something similar to:

ON value GOTO 100, 200, 300

There was also a "shorthand" version of IF

 IF X = 50 GOTO 100: GOTO 200

So this begs the question of whether or not there could be a different syntax to accomplish this... such as:

If {expression_list} Return {return_list}

So it could be something like...

If {value < 0, value = 0, value > 0} Return {"Negative", "Zero", "Positive"}

If {value, Not value} Return {"True", "False"}

The expression list and the return list would need to, of course, match in length other an compiler error would occur.

I'm not saying that this is something that should be done... I just feel that forcing a Select Case into this doesn't feel like the way to go.