The regex | (or) operator splits the pattern left or right unless explicitly grouped. Group it using (pattern) if you need to use the match later, or as a non-capturing group (?:pattern) if you do it for clarity.

I used to think there was some magic rule about how | decided where to split, but it’s simply: characters and subpatterns concatenate into a single pattern first, then | splits the entire thing left and right unless you explicitly group it. That’s because | has the lowest precedence so all other operations happen first.

So while I used to think that prefix_cat|dog would match prefix_cat and prefix_dog, it actually matches prefix_cat and then dog.

And that exact problem in a real-world example, to find if a page is linking to another, both relative or full URL:

Recycling bins are for packaging, not the products themselves. Wooden ice cream stick? That’s “other,” it’s part of the product, at least in Karlstad. The wrapper? That goes in the appropriate recycling bin based on material.

This seems to be based on EU law, which makes sense, so I’ll assume the gist of this is true in other EU countries too.

YAML does not support unsplatting lists (basically, merging list items inline like you can with objects) and that’s intentional.