> On Mar 9, 2018, at 6:24 PM, Brian Goetz <[email protected]> wrote:
>
> . . . That gets us down to:
>
> record Foo(int num, String unrelated) {
> Foo(int num, String unrelated) {
> if (num <= 0) ...;
> }
> }
>
> Which is slightly better. The remaining repetition is the argument list of
> the constructor is repeated. On the one hand, this seems at first to be
> incompressible: Java members have signatures. But if we're willing to do
> something special for records, we can take advantage of the fact that a
> record _must_ have a constructor (the "primary constructor") that matches the
> record signature, and let the user leave this out if they are declaring an
> explicit primary constructor:
>
> record Foo(int num, String unrelated) {
> Foo {
> if (num <= 0) ...;
> }
> }
>
> or
>
> record Foo(int num, String unrelated) {
> primary-constructor {
> if (num <= 0) ...;
> }
> }
>
> or similar could be a shorthand for declaring the full primary constructor
> signature. I think that gets you down to your minimum, without losing much
> in the way of readability.
Ya know, as long as we are talknig about a mandatory constructor, if that
special keyword “primary-constructor” were spelled “required”, it would look
achingly familiar:
record Foo(int num, String unrelated) {
required {
if (num <= 0) ...;
}
}
Compare to:
record Foo(int num, String unrelated)
requires
(num <= 0)
{
}
—Guy
