Lab 5 · Under the hood: opening balances (pad & balance)

Your accounts exist (Lab 4), but beancount assumes they start at zero. A real credit card you've held for years already owes money; an airline account already has miles. This lab is about telling the ledger the truth as of today — and doing it safely.

You'll learn two new directives by writing them yourself:

• balance — assert what an account should hold on a date (a checkpoint)
• pad — fill the gap automatically so an opening balance just works, without typing years of history