Pattern Matching for instanceof (Preview 2)

forax at forax at
Thu Feb 6 22:21:36 UTC 2020

----- Mail original -----
> De: "Brian Goetz" <brian.goetz at>
> À: "Remi Forax" <forax at>, "jan lahoda" <jan.lahoda at>
> Cc: "amber-spec-experts" <amber-spec-experts at>
> Envoyé: Jeudi 6 Février 2020 23:04:05
> Objet: Re: Pattern Matching for instanceof (Preview 2)

>> I see two questions:
>> - the grammar allows to mix var and non-var for a given reference type, i think
>> that should only permitted if the non var is a deconstruction itself ?
> More generally, any pattern can appear nested inside a deconstruction
> pattern -- another deconstruction pattern, a var (any) pattern, a type
> pattern, a constant pattern ... we may not have them all right now, but
> any pattern will do.

var is not really any, it's an inferred type pattern.
'_' is any, no ?

>> - must the identifier of a pattern argument be the same name as the
>> corresponding record component ?
>>    To be coherent with the fact that constructors requires the same names.
> Nope!  This is the use site; the client can name their locals however
> they like.  Invocation of deconstructors, like constructors, is positional.

Ok, make sense.


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