Switch expressions -- some revisions

Brian Goetz brian.goetz at oracle.com
Fri Dec 15 00:24:39 UTC 2017

I think there are good arguments on both sides of this issue. Because, 
expression switch and statement switch, they have both commonality and 

Overall, my gut sense is that "lumping" is better than "splitting" 
here.  Especially as there are so many possible dimensions of lump vs 
split: expression vs statement, constants vs patterns, exhaustive vs 
not, fallthrough vs not, colons vs arrows, etc.

Your point about "people of the future" is a good one.  When a "Java 9 
person" encounters expression switch for the first time, the lumping may 
help (or might make it harder) to understand the commonalities vs 
differences.  On the other hand, a "Java 15 person" looking back in 
history may have a different perspective, and we should design for the 
future person as being a newbie is (hopefully) a short-lived experience.

So, for where we want to land, does it make more sense to accentuate the 
commonality ("do exactly one of these things, based on these choices") 
or the difference ("operate via side-effects vs computation")?  My sense 
is the former, but others may have different opinions.

On 12/14/2017 5:59 PM, Remi Forax wrote:
> but i still think we should no have the same keyword for the switch 
> and the expression switch (so we will not name i the expression 
> switch), whatever keyword is fine for me but not switch, it's not the 
> same semantics.

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