Pattern matching: next steps after JEP 405

[Brian Goetz]

I'm sorry, I have no idea what argument you are trying to make.  Start 
from the beginning.

On 5/20/2022 1:27 AM, forax at univ-mlv.fr wrote:
>
>
> ------------------------------------------------------------------------
>
>     *From: *"Brian Goetz" <brian.goetz at oracle.com>
>     *To: *"Remi Forax" <forax at univ-mlv.fr>
>     *Cc: *"amber-spec-experts" <amber-spec-experts at openjdk.java.net>
>     *Sent: *Thursday, May 19, 2022 3:05:07 PM
>     *Subject: *Re: Pattern matching: next steps after JEP 405
>
>
>
>         When you have a type pattern X in a middle of a pattern *and*
>         you have conversions, then there is an ambiguity,
>         does instanceof Box(X x) means
>           Box(var v) && v instanceof X x
>         or
>           Box(var v) && X x = (X) v;
>
>
>     This is not an ambiguity in the language, it is confusion on the
>     part of the reader :)
>
>     In any case, I'm not following your argument here. 
>
>
> If you have both a type pattern and allow conversions, you have
>   Box(X) is equivalent to Box(var v) && v instanceof Y y && X x = (X) y
>
> How do you find Y ?
>
> And yes, the bar is not only that Y has to be unique for the compiler, 
> it has also to be obvious for the human reader too.
>
> Rémi
>
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