Register [[.rust_class just as $.rust_class

[shrektan]

Hi,

I believe it's necessary to register [[ S3 method for exported Rust Class as well.

The reason is that, only so, we can call the method dynamically, e.g., method <- "method_abc"; RustClass[[method]]().

This is not possible for $.

Thanks.

[yutannihilation]

Sounds good to me.

[andy-thomason]

This is great. Good to update the Change log, too.

We may export trait methods to s3 methods in the future in which case we may optionally overload [[ as Index, but we
can cross that bridge when we come to it.

[shrektan]

Sorry that I didn't notice there's a test package that needs to be checked. Now it should be ok.

[yutannihilation]

Thanks for updating. One more thing, could you add a small test to verify x[["foo"]]() works as the same as x$foo() around here?

extendr/tests/extendrtests/tests/testthat/test-classes.R

Line 5 in a59d65c

expect_equal(x$a(), 10L)

[shrektan]

@yutannihilation added.

[yutannihilation]

Looks good, thanks! I'll wait for a while before merging to see if there's any concern from other maintainers.

[yutannihilation]

I'm merging now. Thanks for the contribution!