Derive 1. an account tree and 2. each account's total exclusive and inclusive changes from a list of postings. This is the core of the balance command (and of *ledger). The accounts are returned as a list in flattened tree order, and also reference each other as a tree. (The first account is the root of the tree.)

Convert an AccountName tree to an Account tree

Tie the knot so all subaccounts' parents are set correctly.

Get this account's parent accounts, from the nearest up to the root.

List the accounts at each level of the account tree.

Map a (non-tree-structure-modifying) function over this and sub accounts.

Is the predicate true on any of this account or its subaccounts ?

Add subaccount-inclusive balances to an account tree.

Remove all subaccounts below a certain depth.

Remove subaccounts below the specified depth, aggregating their balance at the depth limit (accounts at the depth limit will have any sub-balances merged into their exclusive balance).

Remove all leaf accounts and subtrees matching a predicate.

Flatten an account tree into a list, which is sometimes convenient. Note since accounts link to their parents/subs, the tree's structure remains intact and can still be used. It's a tree/list!

Filter an account tree (to a list).

Sort each level of an account tree by inclusive amount, so that the accounts with largest normal balances are listed first. The provided normal balance sign determines whether normal balances are negative or positive.

Search an account list by name.