Disambiguation

[stereobooster]

I thought if it is possible to create disambiguation operators, see

• https://goccmack.github.io/posts/2020-05-31_gogll/#disambiguating-the-parse-forest
• https://spoofax.dev/references/sdf3/disambiguation/

And I realized that priority (or precedence) should be possible to express with ordered choice (from PEG):

<E>  = <"("> E <")"> / or / and / id
and  = E <"&"> E
or   = E <"|"> E
id   = #"\w+"

And it gives correct result for insta/parse. But when I use insta/parses (s). It gives me both trees as if I was using | instead of /. There are only two possible trees for a|b&c.

So I wonder why? And wouldn't it be beneficial (for memory/performance) to throw away second tree?