One payment had to name one document and could take no discount or
processor fee, so paying several invoices from one deposit meant several
entries and the fee had nowhere to go. This adds the kernel's exact
settlement arithmetic (applications total, net deposit), a Ledger::settle
that posts one entry for a customer's or vendor's documents, and the gross
method and gross fee A-8/A-4 chose.
- kernel::settle: sum(cash)+sum(discounts)=applications, sum(cash)-fee=
deposit, None on overflow or a negative deposit. Kani settle_is_exact
plus the Decimal bridge.
- Ledger::settle / settlement_lines: one party and one kind per
settlement, one application per document, each cash+discount within
payment_room; a discount within the terms (discount_max and
discount_by) needs no reason, a larger or later one does; a bill with
an asset line is refused with D-49's remedy; a fee is a customer
payment's only and posts gross.
- Rows are payment lines in application order, then discount lines, the
fee line and the cash line, so a journaled event's line indices are
stable; replay tags exactly the line an event names and leaves an
unmatched line unattached (never refuses).
- receive_payment_with and pay_bill_with become one-application calls.
- Roles: sales_allowances (4100), purchase_discounts (6995) and
payment_processing_fees (6060), constants used on demand but not added
to control_accounts() (existing charts may use those codes for other
things).
- Lean: settle posts through Step.document, so settle_posts_a_document_step
and settle_unattached, no new constructor; both in Audit.lean.
- Core tests: bill_on_terms_with_discount, late_discount_needs_a_reason,
discount_on_an_asset_bill_is_refused_with_the_remedy,
a_fee_posts_gross_to_receivables_and_net_to_the_bank,
a_settlement_names_its_lines_and_refuses_a_document_twice, and
equipment_bill_payment_is_investing_cash in the cash-flow suite.
- Bookspec B-42 is stated, with its id BS-arap-6; the catalogue and index
now record it as CONVENTION.
just check and just prove green.
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