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

[Per-Ake Minborg]

Maybe certain values for float and double should be allowable (e.g. NaN (matching all variants), POSITIVE_INFINITY, NEGATIVE_INFINITY and zero (matching any zero value))? These are clearly defined. All other values would render a compile-time error? (many question marks here) /P
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From: amber-dev <amber-dev-retn at openjdk.org> on behalf of Remi Forax <forax at univ-mlv.fr>
Sent: Thursday, January 26, 2023 2:15 PM
To: Angelos Bimpoudis <angelos.bimpoudis at oracle.com>
Cc: amber-dev <amber-dev at openjdk.org>
Subject: Re: Draft JEP on Primitive types in patterns, instanceof, and switch



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From: "Angelos Bimpoudis" <angelos.bimpoudis at oracle.com>
To: "amber-dev" <amber-dev at openjdk.org>
Sent: Thursday, January 26, 2023 10:48:47 AM
Subject: Draft JEP on Primitive types in patterns, instanceof, and switch
Hello all,

I would like to share this draft JEP with you about primitive types in patterns, instanceof, and switch:

https://openjdk.org/jeps/8288476

"Enhance pattern matching by allowing primitive types to appear anywhere in patterns. Extend instanceof to support primitive types, and extend switch to allow primitive constants as case labels."

Comments very much welcomed!

Many thanks,
Angelos


I still think that the semantics proposed for pattern matching on primitive types is useless complexity with the perverse side effect of normalizing the usage of "default" in pattern matching (too many examples of this JEP are using "default") but we already discussed that.

Allowing switching on double and float constants is just wrong.
Rust is actually trying to remove that feature
  https://github.com/rust-lang/rust/issues/41255

I see no point to make the same mistake.

Otherwise, the rest is fine.

Rémi

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