Install Agda - ‘cabal not found’

I want to use Agda in iSH.

Agda seems to suggest you need cabal to install it. I don’t know why (as in, if you could build it from source, without Cabal). Perhaps Agda is written in Haskell.

https://agda.readthedocs.io/en/v2.6.3/getting-started/installation.html

If I try a straightforward approach, I can see cabal here:

https://pkgs.alpinelinux.org/package/edge/community/x86_64/cabal

But apk add cabal returns:

iPhone:~# apk add cabal
ERROR: unable to select packages:
cabal (no such package):
required by: world[cabal]
iPhone:~#
It appears for some reason iSH does not have the complete apk packages:

https://ish.app/blog/default-repository-update

But I added them from here:

echo https://dl-cdn.alpinelinux.org/alpine/v3.14/main >> /etc/apk/repositories
echo https://dl-cdn.alpinelinux.org/alpine/v3.14/community >> /etc/apk/repositories
sed -i -e '/http:\/\/apk.ish.app/d' /etc/apk/repositories
https://github.com/ish-app/ish/wiki/Using-Alpine-Linux-repositories

and did apk update.

But it still doesn’t find them.

Why?