For my ledger-cli port I am now working on a feature that enables the user to specify a report format using a domain specific language. This is very flexible for the advanced user, who will be able to create reports tailored to specific needs. I will use it myself to automate some of my tax requirements.
Not knowing any better, I am doing this using pest, which I think is an elegant way to do it. But I was wondering, how would you go about it?