How to list all installed versions of a versioned formula?

[mislav]

Output of brew config

n/a

Output of brew doctor

n/a

Description of issue

I have installed multiple different @-versions of the openssl formula:

$ `brew --prefix openssl@1.1`/bin/openssl version
OpenSSL 1.1.1v  1 Aug 2023

$ `brew --prefix openssl@3.0`/bin/openssl version
OpenSSL 3.0.11 19 Sep 2023 (Library: OpenSSL 3.0.11 19 Sep 2023)

$ `brew --prefix openssl@3`/bin/openssl version
OpenSSL 3.1.3 19 Sep 2023 (Library: OpenSSL 3.1.3 19 Sep 2023)

For scripting purposes, I'm now trying to find a brew command incantation that can list all the different openssl@* formulae that I have installed.

This does not do what I expect:

$ brew list --versions openssl
openssl@3 3.1.2 3.1.3

This lists all installed "versions" of the openssl@3 formula, but these are not the droids I'm looking for. I'm looking for all installed openssl@* versioned formulae and don't want to scope the search to openssl@3 specifically.

This gets me close, but seems wasteful/wrong:

$ brew list | grep ^openssl@
openssl@1.1
openssl@3
openssl@3.0

I imagine that brew list could get relatively slow on systems where there a ton of formula installed, but that's only a guess. Ultimately, I don't want to list all installed formula; I just want ones named openssl@*. It feels wrong to have to perform filtering with grep rather than having Homebrew do the filtering for me.

Does anyone know of a better way?

[SMillerDev]

No, that seems like the best way to me. brew list is just ls under the hood, so it should be pretty quick.