The mortgage payments always confused me and that link has a good explanation of how it works. Have you used that code base in your own system or just the principles? I don’t know Haskell so not sure how much I can/need to modify.
Do you want to share what's confusing about mortgage payments?
You have a balance that accrues a monthly interest. Separately, you're told that you're owed a monthly payment. If monthly payment > interest, then the difference is subtracted from the balance. No need for haskell.
Loans can be confusing in double entry accounting for the uninitiated.
On the accounting side you have liabilities:mortgage which would only include the principal. Then for an individual bill you have to debit liabilities:mortgage the principal portion and debit expenses:interest the interest portion.
I’m not sure how mortgage bills usually come but for my auto loan the principal vs interest were not noted on the bill, so i had to calculate via apr myself for each payment for which the interest accrued daily. If i imported those payments from my bank statement or the bill i would not be able to enter the transaction correctly without doing the math.
For calculating interest automatically upon entry based on the rate and payment amount and date I used python iirc as i used beancount, but that was a while ago.
Yes, I'm using parts of this codebase. But Haskell is only being used as a build tool, so you can replace it with anything that you're comfortable with, like make, bazel, ...
