assets package

AccountKind is an account's kind as a word: "asset" for 1590, "expense" for 5500. The second result is false for a code this chart does not hold.

It exists because the chart's kinds are otherwise unobservable from outside. Both accounts are debit-normal, so neither Balance nor Equation can distinguish them, and the package doc's claim that 1590 is a contra-ASSET rather than a second expense account would be an assertion in a comment with nothing behind it. Opening 1590 as an Expense instead would leave every other read in this file identical.

AccumulatedAt is Cost - CarryingAt(n): what the contra-asset balance for one asset SHOULD be once period n is booked.

AccumulatedCredit is the POSITIVE accumulated-depreciation figure: the credit balance of 1590, i.e. -RawDelta.

AssetCount is how many assets a register holds, retired ones included.

AssetInfo reports an asset's whole stored state in one read.

method is "straight-line" or "declining-balance"; rateNum and rateDen are 0 for a straight-line asset.

Balance is an account's balance in its NORMAL direction. For 1590 that is debit-normal and so reads negative; AccumulatedCredit is the figure a reader of a contra-asset wants.

BookThrough posts the depreciation charge for every period that has completed since this asset was last booked, and returns the period the asset is now booked through.

It is IDEMPOTENT: calling it twice in one block, or twice in one period, posts once. Calling it after skipping ten periods posts the whole span as one entry, for the same total a caller who ran it every period would have reached — p/depreciation's Charge telescopes exactly, so booking cadence cannot change the total booked.

A ZERO charge advances the mark and posts nothing. That is not a shortcut: journal rejects a posting of zero (ErrInvalidAmount), while a degenerate declining schedule legitimately charges zero, and the invariant is preserved exactly because AccumulatedAt is equal at both marks in precisely that case.

Panics if the asset is retired, or if the book is full.

BookedAmount is the cumulative expense posted for one asset.

BookedThrough is the high-water mark: the whole periods already charged.

Capacity reports how many more assets and entries a register can take.

CarryingAt is an asset's carrying amount after n whole periods: Cost at n <= 0, Salvage at every n >= Life. It reads the SCHEDULE and is independent of what has been booked.

CrossFoot is the register-wide check: the sum of every asset's booked amount against the credit balance of 1590.

The identity is EXACT, not approximate, and the reason is structural: this realm exposes no general posting entrypoint, so it is its book's only writer and bookSpan is the only code that posts. Adding a general Post would destroy this check, which is the cost of adding one.

retired assets are included: their charges were really incurred and the 1590 credit they produced does not disappear when the asset stops.

Due is the charge BookThrough would post for an asset right now. It is 0 for a retired asset, for an asset with no newly-completed period, and for a degenerate declining schedule that has not reached its final period.

EntryCount is how many entries a register's book holds.

Equation is the accounting equation: debit-normal against credit-normal. Both sides offset at 0 for this chart, because the only entry is an expense debit against a contra-ASSET credit — both legs are debit-normal accounts, so the expense adds and the contra subtracts.

ExpenseDebit is the total depreciation expense recognised: the debit balance of 5500.

FullyDepreciatedAt is the height at which an asset first carries only its salvage value: placedAt + Life*periodBlocks. Validated at placement, so it cannot fail afterwards.

HasRegister reports whether an address has a register.

Height is the chain height this realm dates entries and periods with. Exposed so a caller can predict what BookThrough will book.

Invariant is the per-asset derivation check:

1bookedAmount == schedule.AccumulatedAt(bookedThrough)

It returns the two figures and whether they agree. A false here means the realm posted an amount its own schedule does not imply, which no code path in this realm can produce — which is exactly why it is worth exporting: the claim is checkable by a third party rather than asserted in a comment.

IsBalanced reports whether the book's debits equal its credits.

IsRetired reports whether an asset has been retired.

Label is an asset's label.

OpenRegister creates the caller's register and opens its two accounts. It panics if the caller already has one.

The chart is opened HERE rather than on demand, and the book is created with a cap of exactly two accounts. Both facts are load-bearing: they are why this realm is its book's only writer and why the CrossFoot identity is exact rather than approximate.

OpenedAt is the height a register was created.

PeriodsElapsed is the whole periods completed for an asset at the current height, whether or not they have been booked. For a retired asset this keeps increasing while BookedThrough does not, which is the intended difference and is why both are exported.

Place records a straight-line asset placed in service at the current height, and returns its id.

Nothing is posted: at placement zero periods have completed, so the charge is zero and a zero posting is not a valid journal entry. The first charge becomes bookable at placedAt + periodBlocks.

PlaceDeclining records a declining-balance asset charging num/den of the remaining carrying amount each period. Double-declining over a 10-period life is num=2, den=10.

Two properties of that method are inherited from p/depreciation and are visible in this realm's numbers, so they are repeated here. The final period absorbs whatever remains above salvage, so the last charge can be much larger than the one before it. And a schedule whose per-period charge truncates to zero (cost*num < den) never depreciates until that final period — Due reads 0 for its whole life, which is the schedule behaving as specified and not a stuck register.

RawBalance is an account's Debits - Credits, with no normal-direction adjustment.

Rederive re-walks every posting in the book and reports whether the account totals agree with the journal.

It is a FREE read, unlike r/books' owner-only equivalent. The divergence is deliberate: this realm's claim is that its postings follow from its stored schedules, and a claim only the owner can check is not worth making. The cost is linear in the posting count, which is what MaxEntriesPerRegister bounds.

Registers is how many registers exist. There is deliberately no way to enumerate them or to aggregate across them: such a total would be the sum of every stranger's self-reported cost figures.

Render shows the realm index at "/" and one owner's register at "/<address>".

Retire books the asset through the current period and then stops it permanently. It returns the final amount posted, which may be zero.

The booking is not optional and not separable: see the package doc. After this call the asset accrues nothing, BookThrough on it panics, and every historical charge stands.

An asset already at or past the end of its life still retires cleanly — CarryingAt clamps at Salvage from Life onwards, so the final charge is whatever had not yet been booked and is zero if nothing had.

IT PANICS IF THE BOOK IS FULL AND A CHARGE IS DUE, AND THAT REFUSAL IS PERMANENT. The booking is not separable, journal's Post is fail-closed before it writes, and a panic reverts the whole transaction — so an asset with an unbooked charge on a register that has reached MaxEntriesPerRegister can never be retired. BookThrough's identical panic is harmless (the charge simply stays unbooked and can be booked later if the book ever has room, which it never will, there being no archive); this one strands the asset permanently in the live state.

It is reachable, and the arithmetic is the same one MaxEntriesPerRegister carries: about seven MaxLife assets booked period-by-period fill the book. The remedy is the same one the entry cap already has — a second register under a second address — and it has to be arranged BEFORE the book fills, which is why Capacity is exported and why the register page prints the entry headroom. Making Retire freeze without booking would be the obvious alternative and is refused: it would forfeit a charge that was genuinely incurred, which is the one thing this realm exists not to do.

Totals is the book's total debits and credits. They are equal after every charge, because every entry is a matched pair.