I was practicing that trick all morning!
I agree that `Foo[P]` can be saved for later.
In case it wasn’t clear in my previous message, I also think that
splicey stuff like `new Foo[]{ ...as, b, c, ...ds, e }` and the
corresponding slicey patterns can *also* be saved for later.
In fact, the slice/splice stuff seems like it is best situated in a
larger design exercise for “collection literals” whatever those are.
Basically, that would be where Lisp’s backquote-comma get inherited
by Java.
On 9 Sep 2022, at 17:16, Brian Goetz wrote:
John pulled a nice Jedi-mind-trick on me, and pointed out that we
actually have two creation expressions for arrays:
new Foo[n]
new Foo[] { a0, .., an }
and that if we are dualizing, then we should have these two patterns:
new Foo[] { P0, ..., Pn } // matches arrays of exactly length
N
new Foo[P] // matches arrays
whose length match P
but that neither
new Foo[] { P, Q, ... } // previous suggestion
nor
new Foo[L] { P, Q } // current suggestion
correspond to either of those, which suggests that we may have
prematurely optimized the pattern form. The rational consequence of
this observation is to do
new Foo[] { P0, ..., Pn } // matches arrays of exactly length
N
now (which is also the basis of varargs patterns), and once we have
constant patterns (which are kind of required for the second form to
be all that useful), come back for `Foo[P]`.
