Pattern matching improvements

[Brian Goetz]

We take inspiration from many sources, including many existing languages that have pattern matching.

I think what you’re asking is: “have you considered List patterns”.  And indeed, we have.  List patterns are the dual to list literals (more generally, collection patterns are the dual to collection literals); we would consider introducing collection patterns when we are able to treat them holistically with collection literals.  However, of all the pattern matching features one could craft “have you considered X” for, list patterns are among the weakest, and so these are likely to be lower priority than other pattern matching features in the pipeline (e.g., varargs patterns, constant patterns, etc.).

On May 29, 2024, at 7:58 AM, Georgi Stoyanov <gstoyanov at live.com<mailto:gstoyanov at live.com>> wrote:

Hey folks,
I'm really excited about the new Java features that keep getting added, and I had an idea I wanted to share. Have you thought about introducing a pattern matching feature similar to Scala’s, which allows for more concise and readable code?
In Scala, you can match a list that starts with a specific element without having to spell everything out. For example:
case List(_, 2, _*) => "I only care that this list has 2 as the second element"
case Person("Alice", age) => "It's Alice"

This approach makes the code less verbose and lets you focus directly on the elements you care about. It’s a lot cleaner than extracting elements and comparing them separately, which is what we do now in Java.
I think adding something like this to Java would be a big win, making pattern matching more powerful and the code more readable.
Just wanted to throw this idea out there and see what you all think.

Kind Regards,
Georgi Stoyanov

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