wanderbooks/bookspec/README.md

bookspec: examples (seed)

bookspec is the formal accounting specification planned in plan/served.md (P13, D-34): every rule stated normatively, sourced to its authority, with a symbolic form and concrete examples, independent of any engine. Its own repository comes later. Until then this directory holds its first examples: P3's regression tests, each written here as it is built, so the spec starts from cases a real engine got wrong.

Every example is checked against wanderbooks on every cargo test (crates/ledger-core/tests/bookspec.rs, and for the formats appendix crates/ledger-package/tests/package.rs): an example the engine disagrees with fails the build, so the examples can't rot. An expected value is worked by hand from the cited source, never copied from an engine's output.

The shape of an example

One TOML file per example in examples/, named for its id.

id = "cash-flow.reversed-property-contribution"   # stable; never reused
title = "A property contribution reversed the same day"
rule = "One normative sentence: what MUST (or MUST NOT) hold."
status = "AUTHORITY"            # AUTHORITY | CONVENTION | CHOICE
sources = ["ASC 230-10-45-24", "ASC 230-10-50-3"]   # exact citations
tags = ["accrual", "book", "us"]                     # applicability

[setup]
currency = "USD"                # ISO 4217
fiscal_year_start = "01-01"     # MM-DD
basis = "accrual"               # accrual | cash
rounding = "half-even"          # half-even | half-away-from-zero |
                                # largest-remainder: how a figure is
                                # rounded to the currency's minor unit,
                                # where a rule rounds (none here)

[[setup.accounts]]
code = "1000"
name = "Cash"
type = "asset"                  # asset | liability | equity | revenue | expense

[[events]]                      # in order; event N is entry #N
date = "2026-01-10"
description = "Property contributed"
lines = [
  { account = "1500", side = "debit", amount = "2340.00" },
  { account = "3000", side = "credit", amount = "2340.00" },
]

[[events]]
date = "2026-01-10"
description = "Reverse entry 1"
reverses = 1                    # the event (1-based) this one reverses:
                                # its lines, sides flipped; no `lines` here

[[expect]]
query = "cash_flow"             # what is asked of the books (see below)
from = "2026-01-01"             # inclusive
to = "2026-12-31"               # inclusive (a query as of a day: as_of)

[expect.values]                 # every value an exact decimal string
operating = "0.00"

Events count from 1, as entries do: the first [[events]] is event 1 (entry #1), and reverses = N reverses the Nth event, one before it; reverses = 0 names no event and is refused. An event is an entry (lines), a reversal (reverses), a close (close, below) or a bill (bill, below), exactly one of them, and posts entry #N. A change that posts no entry (a rename, a policy) is a [[changes]] entry instead (below), so the numbering holds. A key the shape doesn't have is refused too, never ignored.

rounding names the rule the example's figures are rounded by where one rounds: half-even or half-away-from-zero to the currency's minor unit, or largest-remainder for an amount split among parts (each part rounded down, the units left over to the largest remainders, ties to the part listed first; rules.md B-13). An example that closes to the members declares largest-remainder, the rule a members close splits by.

Required everywhere: the top-level keys, [setup] with its four keys and its accounts, the events, and at least one [[expect]] with values: a figure query's are exact decimal strings ("2340.00", "-12.50"; never a float), a format query's are text (below). Amounts on lines are positive; the side gives the direction.

Optional keys, for the rules that need them

• appendix = "formats" (top level): the example shows an interchange format, not an accounting rule (P13's appendix of formats; the IIF file today). It loads like any other; only it may ask a format query.
• parent on an account: its parent account's code. A parent is declared before its subaccounts.
• header = true on an account: a header, which groups other accounts and takes no postings (it needs no tax category: rules.md B-32).
• tax_category on an account: its tax category, a key of the books' catalog (gross_receipts, office_expense, ...; ledger_core::tax), its link to a line of the return (B-32).
• today (in [setup]): the day the books are asked on, YYYY-MM-DD, in the company's time zone: what an omitted date means (B-30). A query that omits a date needs it.
• cash_accounts, financing_accounts, investing_accounts: arrays of account codes, the statement of cash flows' account roles (ASC 230-10-45-10 to 45-15). The cash and financing accounts are also what a payee is paid from, for vendor_1099_paid (a payment card is neither: its charges go on Form 1099-K; rules.md B-19), and the cash accounts are an IIF file's bank accounts (B-34).
• [[setup.fixed_assets]] { cost_account, accumulated_account, expense_account }: accounts that hold property and equipment (their cost and accumulated depreciation are investing; ASC 230-10-45-12(c), 45-13(c)).
• [[setup.members]] { name, capital_account, share? }: the members of a multi-member LLC. share is the member's share of income, an exact decimal fraction ("0.5", "0.3333"); every member has one or none does, and the shares sum to 1. A close to the members and members_equity need them.
• [[setup.payees]] { name, form }: a payee marked for an information return, form "1099-NEC" or "1099-MISC"; each name once.
• payee on an event: the payee (by name, one of setup.payees) the entry paid. Not on a reversal, which takes its original's, nor on a close.
• close = { start, to, rounding? } as an event: closes the period from start through the event's date (rules.md B-11, B-13), to "members" (split by share, in the order listed) or "retained_earnings". A close to the members splits cumulatively, each close giving each member their split of everything the members' closes have closed less what earlier closes gave them; rounding = "per-close" splits that close's net on its own instead (books from an engine that rounded each close by itself). A close must have something to close: it posts entry #N like any other event.
• bill = { vendor, amount } as an event: a bill from vendor (a name; a payee's record if one has it) for amount, dated and due on the event's date. It posts entry #N: General Expenses (6999) debited and Accounts Payable (2000) credited, each account created with that fixed name when first needed, as the books create a control role's account (B-32).
• [[changes]] { after, rename?, require_tax_category? }: a change that posts no entry, exactly one of rename = { code, name } (rename the account code, B-31) and require_tax_category = "warn" or "refuse" (the policy, B-32; the books start at warn). It is made right after event after (1 to the number of events), once the expectations asked after that event are checked, in the order listed.
• after = N on an expectation: asked of the books after event N (before the changes made after it), not after the last event and every change (1 to the number of events; not on a format query).

Queries and their values

A query over a period takes from and to; a query as of a day takes as_of; the other is refused. A date left out is resolved by the one rule (rules.md B-30) on setup.today: an omitted to is today, an omitted from the first day of the fiscal year that holds to, an omitted as_of today (vendor_1099_paid and the format queries give theirs). A query no crate answers is refused, never skipped.

query	dates	values	checked by
cash_flow	from, to	figures (below)	ledger-core tests/bookspec.rs
trial_balance	as_of	each account's balance by code, debits less credits (a credit balance negative), every account listed	ledger-core tests/bookspec.rs
profit_and_loss	from, to	each revenue and expense account's activity by code, on its normal side, closing entries left out, every one listed; net_income, revenue less expenses	ledger-core tests/bookspec.rs
entry	entry = N, no dates	entry N's lines, "<code>.debit" and "<code>.credit" each the sum of that account's lines on that side, every line of the entry named	ledger-core tests/bookspec.rs
balances	as_of	each account named by code, its balance on its normal side (a member's capital after a loss is negative); the example names the accounts it shows	ledger-core tests/bookspec.rs
members_equity	from, to	the statement of changes in members' equity (rules.md B-13): "<member>.beginning", .contributions, .net_income, .distributions, .other, .ending; the example names the figures it shows	ledger-core tests/bookspec.rs
vendor_1099_paid	from (January 1 of to's year), to	each payee's payments by name, out of the cash and financing accounts (cash_accounts required), every payee listed	ledger-core tests/bookspec.rs
period	from, to, either or both left out	the dates a period report asked with those dates covers, by the one rule (B-30): from, to (YYYY-MM-DD); or refused	ledger-core tests/bookspec.rs
day	as_of, or left out	the day a report as of a day is made as of: as_of	ledger-core tests/bookspec.rs
calendar_year	none	the year a calendar-year count (1099s, party totals) asked without one counts: year	ledger-core tests/bookspec.rs
account_names	none	each account's name by code, as the chart holds it and every report prints it, past periods included (B-31); every account listed, those the books created included	ledger-core tests/bookspec.rs
uncategorized_accounts	none	a list: every account that needs a tax category (revenue or expense, not a header) and has none, with activity or not, "<code> <name>", by code (B-32)	ledger-core tests/bookspec.rs
iif_lines	as_of	formats appendix: the file's lines in order, each its fields joined by tabs, without the CR LF that ends each	ledger-package the_bookspec_iif_example_matches_the_engine
iif_changes	as_of	formats appendix: each text the file writes differently from the books, in file order, as [what, books' text, file's text] (the example's header gives what)	ledger-package the_bookspec_iif_example_matches_the_engine

A figure query is a table ([expect.values], or values = { ... }); a format query, and uncategorized_accounts, an array (values = [ ... ]). period, day and calendar_year give dates and a year, and account_names names, not figures.

A command is tried on a copy of the books, as the books' own command does it, and changes nothing checked after it. It shows no values: it is accepted = true, or refused = "<reason>".

command	keys
rename_account	code, name	rename the account (B-31); accepted, it must move no amount and keep the name trimmed
add_account	account = { code, name, type, parent?, header?, tax_category? }	add the account, under the policy in force (B-31, B-32)
set_tax_category	code, category (left out: clear it)	set or clear the account's tax category, under the policy in force (B-32)

A refusal (a command's, or a period's) is named for what was refused, never by an engine's message: end_before_start (both dates given, the start after the end), start_after_today (only a start, after today, the end an omitted end means), blank, unchanged (the name the account has, trimmed), sibling_has_it (another account under the same parent has the name, ignoring capitals and surrounding space), holds_a_tin (a run of nine digits), not_one_line (a line break, tab or other control character, or past 200 characters), code_taken, and tax_category_required (an account that needs a category left without one under refuse).

cash_flow (rules.md B-14): the statement of cash flows for [from, to].

key	the value
operating, investing, financing	each section's net cash, + in
net_change, cash_beginning, cash_ending	the cash accounts' change and balances
difference	sections less the change in cash: always "0.00"
net_income	revenue less expenses, closing entries excluded
<section>.<N>	entry N's cash in that section (financing.4)
<section>.<N>.on_behalf	of it, what a member or a lender paid or received for the company, no cash account moving (constructive receipt and disbursement)
<section>.count	how many entries the section lists
noncash.<N>	entry N's noncash investing and financing disclosure
noncash.count	how many entries are disclosed
reconciliation.depreciation	depreciation added back
reconciliation.investing_gain_loss	gains and losses whose cash is investing, taken out
reconciliation.noncash_through.<code>	operating movements no cash settled, through that account
reconciliation.other_noncash	other operating movements no cash settled
reconciliation.balance_change.<code>	minus the change in an operating asset or liability

An entry named in a <section>.<N> (or .on_behalf) or noncash.<N> key must be the only such entries when <section>.count or noncash.count is given too; a reconciliation key not given must be zero or absent.

Every example, in any appendix, is loaded by crates/ledger-core/tests/bookspec.rs (every_bookspec_example_holds): its shape (a key the shape doesn't have is refused), its setup, and every event posted. Each query is then checked by the crate that answers it (the table above), so the shape never rots either.

Licence and sources

The examples state rules in their own words with the paragraph cited (FASB's Codification is copyrighted: cited, never copied; see docs/spec/sources/fasb-asc.md). The examples are MIT OR Apache-2.0, as the rest of this repository, until bookspec moves to its own repository (planned: the spec under CC BY 4.0).