Re: [RFC] Disjunctive Normal Form Types
| From: | Anton Smirnov | Date: | Sat, 19 Mar 2022 17:15:28 +0000 |
| Subject: | Re: [RFC] Disjunctive Normal Form Types | ||
| References: | 1 | Groups: | php.internals |
| Request: | Send a blank email to internals+get-117381@lists.php.net to get a copy of this message | ||
On Sat, 2022-03-19 at 16:38 +0000, G. P. B. wrote:
> DNF types are a way to mix intersection and union types together in a
> single type.
> For example:
> - (A&B)|null
> - (Traversable&Countable)|array
Hello George,
I like your proposal. I would like to offer 2 suggestions however:
1. I think that syntax would be cleaner without the parentheses
2. [Future Scope] I would go against non-DNF types. DNF forms a nice
two level structure that's easy to comprehend. Arbitrary expressions
may be too much for runtime checks (correct me if I'm wrong) and will
definitely have high cognitive complexity. And CNF would allow to form
invalid types too easily like (Traversable|null)&Countable
Best,
Anton