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| 1 | +-- SPDX-License-Identifier: MPL-2.0 |
| 2 | +-- Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk> |
| 3 | +-- |
| 4 | +||| Layer 5 (CAPSTONE): one end-to-end ABI SOUNDNESS CERTIFICATE for |
| 5 | +||| ephapaxiser. |
| 6 | +||| |
| 7 | +||| Every prior layer proves one facet of the ABI contract in isolation: |
| 8 | +||| |
| 9 | +||| * Layer 2 (`Ephapaxiser.ABI.Semantics`) — the flagship single-use / |
| 10 | +||| linearity property: a `Fresh` token is `Consumable` (positive control |
| 11 | +||| `freshTokenConsumable`), while a `Spent` token is not. |
| 12 | +||| * Layer 3 (`Ephapaxiser.ABI.Invariants`) — the deeper transition |
| 13 | +||| invariant: consumption is irreversible (NO-RESURRECTION, |
| 14 | +||| `noResurrectionThree`) and identity-preserving. |
| 15 | +||| * Layer 4 (`Ephapaxiser.ABI.FfiSeam`) — the ABI<->FFI seam is sound: |
| 16 | +||| `resultToIntInjective` shows distinct ABI outcomes never collide on the |
| 17 | +||| C wire. |
| 18 | +||| |
| 19 | +||| This module ties the manifest's promise ("enforce single-use linear type |
| 20 | +||| semantics") to the ABI proofs (flagship + invariant) and onward to the FFI |
| 21 | +||| seam, as ONE inhabited value. `ABISound` is a record whose fields are |
| 22 | +||| exactly those proven facts, and `abiContractDischarged : ABISound` is built |
| 23 | +||| solely from the existing exported witnesses/theorems of Layers 2-4. If ANY |
| 24 | +||| prior layer were unsound — if any of those witnesses could not be produced |
| 25 | +||| genuinely — this single value would not typecheck. That is the capstone: |
| 26 | +||| the full ABI contract is discharged together, not facet by facet. |
| 27 | +||| |
| 28 | +||| No axioms anywhere: no `believe_me`, `idris_crash`, `assert_total`, |
| 29 | +||| `postulate`, `sorry`, or `%hint` hacks. Each field is a real value imported |
| 30 | +||| from the layer that proved it. |
| 31 | + |
| 32 | +module Ephapaxiser.ABI.Capstone |
| 33 | + |
| 34 | +import Ephapaxiser.ABI.Types |
| 35 | +import Ephapaxiser.ABI.Semantics |
| 36 | +import Ephapaxiser.ABI.Invariants |
| 37 | +import Ephapaxiser.ABI.FfiSeam |
| 38 | + |
| 39 | +%default total |
| 40 | + |
| 41 | +-------------------------------------------------------------------------------- |
| 42 | +-- The capstone certificate type |
| 43 | +-------------------------------------------------------------------------------- |
| 44 | + |
| 45 | +||| `ABISound` is the end-to-end ABI soundness certificate. Each field is a KEY |
| 46 | +||| proven fact of the ephapaxiser ABI, carried as a genuine value: |
| 47 | +||| |
| 48 | +||| * `flagship` — the Layer-2 flagship property on the canonical positive |
| 49 | +||| control: the concrete fresh token (id 7) IS `Consumable`. |
| 50 | +||| * `invariant` — the Layer-3 NO-RESURRECTION invariant on a concrete |
| 51 | +||| post-state: the spent result (id 3) is NOT resurrectable. |
| 52 | +||| * `ffiSeam` — the Layer-4 FFI-seam soundness: `resultToInt` is |
| 53 | +||| injective, so distinct ABI outcomes never collide on the wire. |
| 54 | +||| |
| 55 | +||| A value of this record can only exist if all three layers are inhabited |
| 56 | +||| together — there is no way to fabricate any field. |
| 57 | +public export |
| 58 | +record ABISound where |
| 59 | + constructor MkABISound |
| 60 | + ||| Layer 2: the canonical fresh token is consumable (flagship single-use). |
| 61 | + flagship : Consumable (MkToken {st = Fresh} 7) |
| 62 | + ||| Layer 3: the spent post-state cannot be resurrected (irreversibility). |
| 63 | + invariant : Not (Resurrection (MkToken {st = Spent} 3)) |
| 64 | + ||| Layer 4: the ABI->C encoding is injective (seam is collision-free). |
| 65 | + ffiSeam : (a, b : Result) -> resultToInt a = resultToInt b -> a = b |
| 66 | + |
| 67 | +-------------------------------------------------------------------------------- |
| 68 | +-- The capstone value: the ABI contract, discharged end-to-end |
| 69 | +-------------------------------------------------------------------------------- |
| 70 | + |
| 71 | +||| THE CAPSTONE. A single inhabited certificate assembled entirely from the |
| 72 | +||| existing exported witnesses/theorems of Layers 2-4: |
| 73 | +||| |
| 74 | +||| * `flagship` := `Semantics.freshTokenConsumable` |
| 75 | +||| * `invariant` := `Invariants.noResurrectionThree` |
| 76 | +||| * `ffiSeam` := `FfiSeam.resultToIntInjective` |
| 77 | +||| |
| 78 | +||| Because each field is the real proof from its layer, this value typechecks |
| 79 | +||| if and only if all prior layers are sound. It is the machine-checked |
| 80 | +||| statement that the manifest promise, the ABI domain proofs, and the FFI |
| 81 | +||| seam form one coherent, discharged contract. |
| 82 | +public export |
| 83 | +abiContractDischarged : ABISound |
| 84 | +abiContractDischarged = |
| 85 | + MkABISound |
| 86 | + freshTokenConsumable |
| 87 | + noResurrectionThree |
| 88 | + resultToIntInjective |
| 89 | + |
| 90 | +-------------------------------------------------------------------------------- |
| 91 | +-- Positive control: the capstone's fields project back to the real proofs. |
| 92 | +-------------------------------------------------------------------------------- |
| 93 | + |
| 94 | +||| POSITIVE CONTROL: the flagship field of the discharged certificate is |
| 95 | +||| definitionally the Layer-2 positive-control witness. Confirms the capstone |
| 96 | +||| genuinely carries the underlying proof rather than some re-derived stand-in. |
| 97 | +||| (Names are module-qualified so they are not implicitly bound as lowercase.) |
| 98 | +public export |
| 99 | +flagshipIsSemanticsControl |
| 100 | + : Capstone.abiContractDischarged.flagship = Semantics.freshTokenConsumable |
| 101 | +flagshipIsSemanticsControl = Refl |
| 102 | + |
| 103 | +||| POSITIVE CONTROL: the FFI-seam field, applied to a concrete colliding pair |
| 104 | +||| (`Ok` with itself), yields the reflexivity proof — the injectivity theorem |
| 105 | +||| is live inside the certificate, not inert. |
| 106 | +public export |
| 107 | +ffiSeamOkOk : Capstone.abiContractDischarged.ffiSeam Ok Ok Refl = Refl |
| 108 | +ffiSeamOkOk = Refl |
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