rules.md B-41 states the write-off: the direct method the owner chose
(A-5), Dr 6990 / Cr 1200 with the receivable tagged, at most what is
owed and at most the least owed from that day on (a partial write-off as
§1.166-3(a) allows), refused on cash-basis books (§1.166-1(e)), its
evidence filed in the same call (§1.166-2(a)); bills are never written
off (ASC 405-20-40-1); and a recovery is not a new movement (D-49): the
same year, reverse the write-off and record the payment; a later year, a
plain entry to a bad-debt-recoveries revenue account, the invoice staying
written off (IRC §111).
bookspec states B-41 for the first time and gives B-38 its example: two
new examples, bad-debt-direct-write-off (two partial write-offs of one
invoice, the balances and the trial balance worked by hand) and
arap-hand-control-posting-refused (a hand line an earlier version wrote
replays, the same line written today is refused). The example schema
gains the dated write_off event, lets a refused entry say so (an entry
posts whole or not at all; older and refused never combine), and its
refusal vocabulary gains untagged_control_line, B-38's control guard.
The registers: docs/architecture.md names the new tool group;
docs/receipt-store.md lists invoice.written_off and what replay does with
it; docs/parity.md records the slice (no row changes status, the floor
stands); docs/testing.md records every test and what P12 must mutate;
docs/verification.md the two Lean theorems and what they cover.
No figure moves: no golden file changed.
bookspec is a specification first: every rule normative and sourced,
every rule demonstrated by concrete examples, and any accounting engine
checked against them through one interface (D-34). This moves the
examples' schema out of the test that happened to parse them and makes
the interface explicit.
- `bookspec/checker` (its own workspace, inside this repository until
the harness is stable): `Example`, `Setup`, `Event`, `Expect`, `Query`,
`Refusal` and the TOML parser, every structure `deny_unknown_fields`,
with `Example::from_toml` checking the cross-field shape (closed lists,
exact decimal amounts, dates, one event kind, `reverses` counting from
1, the shares summing to 1, commands accepted or refused and not both).
- `Engine` (`load`, `apply`, `query`, `claims`) and `Refusal { rule,
reason }`; the refusal's rule is the bookspec identifier, so a refusal
names the rule it belongs to. `Claims` also carries the option an
engine picks for a CHOICE rule.
- `bookspec/runner` drives any `Engine` through the examples and reports
per rule: pass, fail, not claimed. It compares the answer itself; an
engine is never asked whether it agrees with itself.
- `crates/ledger-core/tests/bookspec.rs` is the wanderbooks adapter over
`Store`: the loader parses through the checker, its own checks are
unchanged, and the new `the_runner_reports_every_claimed_rule_green`
runs all 56 examples through the trait. The IIF appendix is answered
through `ledger_package::export_iif`, the code its own test checks.
- `just check` runs the bookspec workspace's fmt, clippy, rustdoc and
tests too, so an example cannot rot (D-34, Z-17).
The plan's trait has four methods and no path for an example's
`[[changes]]` (a rename, the policy, an asset correction), which post no
entry: `change` is the fifth, required so an engine cannot skip those
examples silently. This is reported to the EM as the one departure.
One money rule holds here too: an answer's figures are exact decimal
strings, never JSON numbers, so no engine can round a cent through a
float.
swaits