Draft JEP on Primitive types in patterns, instanceof, and switch

[forax at univ-mlv.fr]

> From: "Guy Steele" <guy.steele at oracle.com>
> To: "Brian Goetz" <brian.goetz at oracle.com>
> Cc: "Remi Forax" <forax at univ-mlv.fr>, "Angelos Bimpoudis"
> <angelos.bimpoudis at oracle.com>, "amber-spec-experts"
> <amber-spec-experts at openjdk.org>
> Sent: Thursday, January 26, 2023 4:25:16 PM
> Subject: Re: Draft JEP on Primitive types in patterns, instanceof, and switch

>> On Jan 26, 2023, at 9:36 AM, Brian Goetz < [ mailto:brian.goetz at oracle.com |
>> brian.goetz at oracle.com ] > wrote:

>> ...

>> For comparing a variable to a constant, representational equality is the obvious
>> interpretation; `case nnn` means "is it the number nnn". This allows you to say
>> `case NaN` and `case -0` and get the right answer (all of these relations agree
>> on what to do about 1.0).

> Careful: I think you had better say “ case -0.0 ”; otherwise the constant
> expression “ -0 ” will be reduced to “ 0 ” and only then converted to
> floating-point representation, producing +0.0 .

> Yes, floating-point is VERY fiddly.
As i read the current spec, case -0 is equivalent to case 0, and you can not have both of them in the same switch. 

> —Guy

Rémi 
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