Merge loops/commerce into architecture: commerce-on-sx revenue vertical

Pricing/promotions/reconciliation as miniKanren relations, order lifecycle as a
flow-on-sx durable flow, order ledger as a persist event stream. Base roadmap
(Phases 1-4) + Phase 5 extensions (line-level attribution, provider-neutral
payment envelope, time-windowed promos, discount-aware tax, stock-constrained
reservation, refund-as-flow) + end-to-end composition proof. 297/297 across 18
suites (bash lib/commerce/conformance.sh).
This commit is contained in:
2026-06-07 14:10:36 +00:00
39 changed files with 3791 additions and 16 deletions

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;; lib/commerce/api.sx — public commerce surface.
;;
;; A session bundles a pricing context with a cart: {:ctx CTX :cart CART}.
;; All operations are pure and return a new session. The total and the
;; per-line breakdown are deterministic functions of (ctx, cart).
;;
;; commerce-checkout is a Phase-3 stub — the order lifecycle is a durable
;; flow that suspends at the SumUp payment boundary.
(define commerce-session (fn (ctx) {:cart empty-cart :ctx ctx}))
(define commerce-ctx (fn (sess) (get sess :ctx)))
(define commerce-cart (fn (sess) (get sess :cart)))
(define commerce-lines (fn (sess) (cart-lines (get sess :cart))))
(define commerce-count (fn (sess) (cart-count (get sess :cart))))
(define
commerce-add
(fn
(sess sku variant qty)
(assoc sess :cart (cart-add (get sess :cart) sku variant qty))))
(define
commerce-remove
(fn
(sess sku variant)
(assoc sess :cart (cart-remove (get sess :cart) sku variant))))
(define
commerce-set-qty
(fn
(sess sku variant qty)
(assoc sess :cart (cart-set-qty (get sess :cart) sku variant qty))))
;; True when the sku exists in the session's catalog snapshot.
(define
commerce-can-add?
(fn (sess sku) (catalog-has? (ctx-catalog (get sess :ctx)) sku)))
(define
commerce-total
(fn (sess) (cart-total (get sess :ctx) (get sess :cart))))
;; Per-line audit breakdown — the "which line contributed what" view.
(define
line-detail
(fn (ctx line) (let ((cat (ctx-catalog ctx))) {:sku (line-sku line) :unit (line-unit-price cat (line-sku line) (line-variant line)) :qty (line-qty line) :variant (line-variant line) :extended (line-extended cat line) :tax (line-tax ctx line)})))
(define
commerce-explain
(fn
(sess)
(map (fn (l) (line-detail (get sess :ctx) l)) (get sess :cart))))
;; Phase 3 — order lifecycle flow (reserve -> pay -> fulfil) lands here.
(define commerce-checkout (fn (sess) {:note "order lifecycle flow lands in Phase 3" :phase 3 :status :not-implemented}))

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;; lib/commerce/attribution.sx — line-level discount attribution.
;;
;; The briefing's marquee backward query: "which line item triggered this
;; discount?". promo.sx computes discount amounts at the class/order level;
;; this layer answers the *scope* question relationally and in both directions:
;; forward — which lines does code C touch? (lines-for-code)
;; backward — which codes touch this line? (codes-for-line)
;; Both are the same relation promo-toucheso run with different vars bound.
;;
;; A :fixed promo is order-level (touches no single line); query those with
;; order-level-codes. Only promos that actually apply (amount > 0) touch lines.
;; Lines whose sku is in product-class `cls`.
(define
class-lines
(fn
(ctx cart cls)
(filter
(fn (l) (= (catalog-class (ctx-catalog ctx) (line-sku l)) cls))
cart)))
;; The lines a promo applies to (its scope). :fixed is order-level → no lines.
(define
promo-lines
(fn
(ctx cart p)
(let
((k (promo-kind p)))
(cond
((= k :percent) (class-lines ctx cart (nth p 2)))
((= k :member)
(if
(= (get ctx :customer) :member)
(class-lines ctx cart (nth p 2))
(list)))
((= k :bundle)
(filter (fn (l) (= (line-sku l) (nth p 2))) cart))
(:else (list))))))
;; Relation: promo `code` touches `line`. Only applying promos (amount > 0)
;; touch anything, so an inapplicable promo contributes no pairs.
(define
promo-toucheso
(fn
(ctx cart ruleset code line)
(fresh
(p)
(membero p ruleset)
(project
(p)
(if
(> (promo-amount ctx cart p) 0)
(mk-conj
(== code (promo-code p))
(membero line (promo-lines ctx cart p)))
fail)))))
;; --- query helpers ---
(define
lines-for-code
(fn
(ctx cart ruleset code)
(run* line (promo-toucheso ctx cart ruleset code line))))
(define
codes-for-line
(fn
(ctx cart ruleset line)
(run* code (promo-toucheso ctx cart ruleset code line))))
(define
line-touched-by?
(fn
(ctx cart ruleset code line)
(not
(empty?
(run
1
c
(mk-conj (promo-toucheso ctx cart ruleset code line) (== c true)))))))
;; Applying order-level (:fixed) promos — discounts with no single line.
(define
order-level-codes
(fn
(ctx cart ruleset)
(run*
code
(fresh
(p)
(membero p ruleset)
(project
(p)
(if
(and
(> (promo-amount ctx cart p) 0)
(= (promo-kind p) :fixed))
(== code (promo-code p))
fail))))))

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;; lib/commerce/cart.sx — cart as an ordered list of line items.
;;
;; A cart is a native list of lines; a line is (list sku variant qty).
;; All operations are pure: they return a new cart, never mutate. Line
;; order is insertion order (stable) so totals are reproducible.
;;
;; cart-lineo is the relational view — because a line *is* a (sku variant qty)
;; tuple, membero queries the cart directly, forward or backward.
(define empty-cart (list))
(define make-line (fn (sku variant qty) (list sku variant qty)))
(define line-sku (fn (l) (nth l 0)))
(define line-variant (fn (l) (nth l 1)))
(define line-qty (fn (l) (nth l 2)))
(define
same-line?
(fn
(l sku variant)
(and (= (line-sku l) sku) (= (line-variant l) variant))))
(define
cart-qty
(fn
(cart sku variant)
(let
((m (filter (fn (l) (same-line? l sku variant)) cart)))
(if (empty? m) 0 (line-qty (first m))))))
(define
cart-remove
(fn
(cart sku variant)
(filter (fn (l) (not (same-line? l sku variant))) cart)))
;; Add qty units; merges into an existing (sku,variant) line in place,
;; otherwise appends a new line at the end.
(define
cart-add
(fn
(cart sku variant qty)
(let
((existing (cart-qty cart sku variant)))
(if
(= existing 0)
(append cart (list (make-line sku variant qty)))
(map
(fn
(l)
(if
(same-line? l sku variant)
(make-line sku variant (+ existing qty))
l))
cart)))))
;; Set the absolute quantity; qty <= 0 removes the line.
(define
cart-set-qty
(fn
(cart sku variant qty)
(if
(<= qty 0)
(cart-remove cart sku variant)
(if
(= (cart-qty cart sku variant) 0)
(append cart (list (make-line sku variant qty)))
(map
(fn
(l)
(if (same-line? l sku variant) (make-line sku variant qty) l))
cart)))))
(define cart-empty? (fn (cart) (empty? cart)))
(define cart-lines (fn (cart) cart))
(define cart-skus (fn (cart) (map line-sku cart)))
;; Total number of units across all lines.
(define
cart-count
(fn (cart) (reduce (fn (acc l) (+ acc (line-qty l))) 0 cart)))
;; Relational view of cart lines.
(define
cart-lineo
(fn (cart sku variant qty) (membero (list sku variant qty) cart)))

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;; lib/commerce/catalog.sx — catalog snapshot + relational accessors.
;;
;; A catalog snapshot is an immutable dict:
;; {:products (list (list sku price class) ...)
;; :variants (list (list sku variant delta) ...)
;; :stock (list (list sku variant qty) ...)}
;;
;; Money is integer minor units (pence/cents). class is a keyword product
;; class consumed later by tax and promotion relations. delta is a signed
;; price adjustment for a variant; qty is on-hand stock for (sku,variant).
;;
;; Accessor relations take the snapshot as the first argument and are fully
;; multidirectional: (producto cat "widget" p c) binds p,c forward;
;; (producto cat s 1000 c) enumerates every sku priced 1000 backward.
(define empty-catalog {:products (list) :stock (list) :variants (list)})
(define make-catalog (fn (products variants stock) {:products products :stock stock :variants variants}))
(define cat-products (fn (cat) (get cat :products)))
(define cat-variants (fn (cat) (get cat :variants)))
(define cat-stock (fn (cat) (get cat :stock)))
;; --- core fact relations ---
(define
producto
(fn
(cat sku price class)
(membero (list sku price class) (get cat :products))))
(define
varianto
(fn
(cat sku variant delta)
(membero (list sku variant delta) (get cat :variants))))
(define
stocko
(fn
(cat sku variant qty)
(membero (list sku variant qty) (get cat :stock))))
;; --- derived relations ---
(define
priceo
(fn (cat sku price) (fresh (c) (producto cat sku price c))))
(define
classo
(fn (cat sku class) (fresh (p) (producto cat sku p class))))
;; Effective unit price of a (sku,variant): base + variant delta.
(define
unit-priceo
(fn
(cat sku variant price)
(fresh
(base delta)
(priceo cat sku base)
(varianto cat sku variant delta)
(pluso-i base delta price))))
;; --- deterministic lookups (first solution under fixed fact order) ---
(define
catalog-price
(fn
(cat sku)
(let
((rs (run 1 p (priceo cat sku p))))
(if (empty? rs) nil (first rs)))))
(define
catalog-class
(fn
(cat sku)
(let
((rs (run 1 c (classo cat sku c))))
(if (empty? rs) nil (first rs)))))
(define catalog-has? (fn (cat sku) (not (nil? (catalog-price cat sku)))))

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#!/usr/bin/env bash
# lib/commerce/conformance.sh — run commerce test suites in one sx_server
# process per suite, emit scoreboard.json + scoreboard.md.
#
# commerce-on-sx builds pricing/promotion as miniKanren relations, so every
# suite loads the miniKanren stack first, then the commerce modules.
set -uo pipefail
cd "$(git rev-parse --show-toplevel)"
SX_SERVER="${SX_SERVER:-/root/rose-ash/hosts/ocaml/_build/default/bin/sx_server.exe}"
if [ ! -x "$SX_SERVER" ]; then
SX_SERVER="hosts/ocaml/_build/default/bin/sx_server.exe"
fi
if [ ! -x "$SX_SERVER" ]; then
echo "ERROR: sx_server.exe not found." >&2
exit 1
fi
SUITES=(catalog cart price api promo stack quote ledger order recon federation attribution payment window nettax stock refund integration)
OUT_JSON="lib/commerce/scoreboard.json"
OUT_MD="lib/commerce/scoreboard.md"
run_suite() {
local suite=$1
local file="lib/commerce/tests/${suite}.sx"
local TMP
TMP=$(mktemp)
cat > "$TMP" << EPOCHS
(epoch 1)
(load "spec/stdlib.sx")
(load "lib/r7rs.sx")
(load "lib/guest/match.sx")
(load "lib/minikanren/unify.sx")
(load "lib/minikanren/stream.sx")
(load "lib/minikanren/goals.sx")
(load "lib/minikanren/fresh.sx")
(load "lib/minikanren/conde.sx")
(load "lib/minikanren/run.sx")
(load "lib/minikanren/relations.sx")
(load "lib/minikanren/project.sx")
(load "lib/minikanren/intarith.sx")
(load "lib/minikanren/matche.sx")
(load "lib/minikanren/defrel.sx")
(load "lib/persist/event.sx")
(load "lib/persist/backend.sx")
(load "lib/persist/log.sx")
(load "lib/persist/kv.sx")
(load "lib/persist/idempotency.sx")
(load "lib/guest/lex.sx")
(load "lib/guest/reflective/env.sx")
(load "lib/guest/reflective/quoting.sx")
(load "lib/scheme/parser.sx")
(load "lib/scheme/eval.sx")
(load "lib/scheme/runtime.sx")
(load "lib/flow/spec.sx")
(load "lib/flow/store.sx")
(load "lib/flow/remote.sx")
(load "lib/flow/host.sx")
(load "lib/flow/api.sx")
(load "lib/commerce/catalog.sx")
(load "lib/commerce/cart.sx")
(load "lib/commerce/price.sx")
(load "lib/commerce/api.sx")
(load "lib/commerce/promo.sx")
(load "lib/commerce/stack.sx")
(load "lib/commerce/quote.sx")
(load "lib/commerce/window.sx")
(load "lib/commerce/nettax.sx")
(load "lib/commerce/stock.sx")
(load "lib/commerce/ledger.sx")
(load "lib/commerce/order.sx")
(load "lib/commerce/refund.sx")
(load "lib/commerce/payment.sx")
(load "lib/commerce/recon.sx")
(load "lib/commerce/federation.sx")
(load "lib/commerce/attribution.sx")
(epoch 2)
(eval "(define ct-pass 0)")
(eval "(define ct-fail 0)")
(eval "(define ct-fails (list))")
(eval "(define commerce-test (fn (name got expected) (if (= got expected) (set! ct-pass (+ ct-pass 1)) (begin (set! ct-fail (+ ct-fail 1)) (append! ct-fails name)))))")
(epoch 3)
(load "${file}")
(epoch 4)
(eval "(list ct-pass ct-fail)")
(eval "ct-fails")
EPOCHS
local OUTPUT
OUTPUT=$(timeout 560 "$SX_SERVER" < "$TMP" 2>/dev/null)
rm -f "$TMP"
# The (list ct-pass ct-fail) result follows its (ok-len 2 N) ack line.
local LINE
LINE=$(echo "$OUTPUT" | grep -oE '^\([0-9]+ [0-9]+\)$' | tail -1)
local P F
P=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\)$/\1/')
F=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\)$/\2/')
P=${P:-0}
F=${F:-0}
echo "${P} ${F}"
}
declare -A SUITE_PASS
declare -A SUITE_FAIL
TOTAL_PASS=0
TOTAL_FAIL=0
echo "Running commerce conformance suite..." >&2
for s in "${SUITES[@]}"; do
read -r p f < <(run_suite "$s")
SUITE_PASS[$s]=$p
SUITE_FAIL[$s]=$f
TOTAL_PASS=$((TOTAL_PASS + p))
TOTAL_FAIL=$((TOTAL_FAIL + f))
printf " %-12s %d/%d\n" "$s" "$p" "$((p+f))" >&2
done
{
printf '{\n'
printf ' "suites": {\n'
first=1
for s in "${SUITES[@]}"; do
if [ $first -eq 0 ]; then printf ',\n'; fi
printf ' "%s": {"pass": %d, "fail": %d}' "$s" "${SUITE_PASS[$s]}" "${SUITE_FAIL[$s]}"
first=0
done
printf '\n },\n'
printf ' "total_pass": %d,\n' "$TOTAL_PASS"
printf ' "total_fail": %d,\n' "$TOTAL_FAIL"
printf ' "total": %d\n' "$((TOTAL_PASS + TOTAL_FAIL))"
printf '}\n'
} > "$OUT_JSON"
{
printf '# commerce Conformance Scoreboard\n\n'
printf '_Generated by `lib/commerce/conformance.sh`_\n\n'
printf '| Suite | Pass | Fail | Total |\n'
printf '|-------|-----:|-----:|------:|\n'
for s in "${SUITES[@]}"; do
p=${SUITE_PASS[$s]}
f=${SUITE_FAIL[$s]}
printf '| %s | %d | %d | %d |\n' "$s" "$p" "$f" "$((p+f))"
done
printf '| **Total** | **%d** | **%d** | **%d** |\n' "$TOTAL_PASS" "$TOTAL_FAIL" "$((TOTAL_PASS + TOTAL_FAIL))"
} > "$OUT_MD"
echo "Wrote $OUT_JSON and $OUT_MD" >&2
echo "Total: $TOTAL_PASS pass, $TOTAL_FAIL fail" >&2
[ "$TOTAL_FAIL" -eq 0 ]

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;; lib/commerce/federation.sx — cross-instance catalog (federated marketplace).
;;
;; STUB: instances are registered in-process; there is no real network or
;; ActivityPub transport here (that lives in the federation service). The point
;; is the relational model: a federated catalog is just the UNION of each
;; instance's product facts, tagged with origin, so the same miniKanren
;; relations answer cross-instance questions — "which instances sell this sku?",
;; "which is cheapest?" — as backward queries, no new query engine.
(define federation-stub? true)
(define make-federation (fn (instance cat) {:instances (list (list instance cat))}))
(define
federation-add
(fn
(fed instance cat)
(assoc
fed
:instances (append (get fed :instances) (list (list instance cat))))))
(define federation-instances (fn (fed) (map first (get fed :instances))))
;; Flatten to (instance sku price class) origin-tagged tuples.
(define
fed-products
(fn
(fed)
(reduce
(fn
(acc pair)
(let
((instance (first pair)) (cat (nth pair 1)))
(append
acc
(map (fn (p) (cons instance p)) (get cat :products)))))
(list)
(get fed :instances))))
;; --- relations over the federated catalog (multidirectional) ---
(define
fed-producto
(fn
(fed instance sku price class)
(membero (list instance sku price class) (fed-products fed))))
(define
fed-priceo
(fn
(fed instance sku price)
(fresh (c) (fed-producto fed instance sku price c))))
;; --- query helpers ---
;; Which instances carry a sku? (backward query)
(define
instances-with-sku
(fn (fed sku) (run* inst (fresh (p c) (fed-producto fed inst sku p c)))))
;; All (price instance) offers for a sku, in federation order.
(define
sku-offers
(fn
(fed sku)
(run*
pair
(fresh
(inst p c)
(fed-producto fed inst sku p c)
(== pair (list p inst))))))
;; Cheapest (price instance) for a sku — the deterministic selection layer.
(define
cheapest-offer
(fn
(fed sku)
(let
((offers (sku-offers fed sku)))
(if
(empty? offers)
nil
(reduce
(fn (best x) (if (< (first x) (first best)) x best))
(first offers)
offers)))))

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;; lib/commerce/ledger.sx — the order ledger as a persist event stream.
;;
;; Each order is an append-only stream "order/<id>" in a persist backend.
;; Order state is never stored directly — it is a projection (fold) over the
;; events, so the ledger is the single source of truth and replays identically.
;;
;; Lifecycle events:
;; :created quote snapshot {:subtotal :discount :tax :total :codes ...}
;; :reserved stock reserved
;; :paid {:amount :ref} — recorded idempotently on the payment ref
;; :fulfilled order shipped/delivered
;; :cancelled / :refunded
;;
;; Idempotency: the SumUp webhook can fire twice for one payment. order-pay
;; uses persist/append-once keyed by the payment ref, so a replayed webhook
;; yields the SAME :paid event without double-recording. Reconciliation then
;; detects genuine mismatches (paid != ordered) across the whole ledger.
(define order-stream (fn (order-id) (str "order/" order-id)))
;; --- writes ---
(define
order-create
(fn
(b order-id at quote)
(persist/append b (order-stream order-id) :created at quote)))
(define
order-reserve
(fn
(b order-id at data)
(persist/append b (order-stream order-id) :reserved at data)))
;; Idempotent on payment ref — a replayed webhook does not double-record.
(define
order-pay
(fn
(b order-id ref at amount)
(persist/append-once b (order-stream order-id) ref :paid at {:amount amount :ref ref})))
(define
order-fulfil
(fn
(b order-id at data)
(persist/append b (order-stream order-id) :fulfilled at data)))
(define
order-cancel
(fn
(b order-id at reason)
(persist/append b (order-stream order-id) :cancelled at {:reason reason})))
(define
order-refund
(fn
(b order-id ref at amount)
(persist/append-once
b
(order-stream order-id)
(str "refund/" ref)
:refunded at
{:amount amount :ref ref})))
;; --- reads ---
(define
order-events
(fn (b order-id) (persist/read b (order-stream order-id))))
;; --- projections over an event list ---
(define
order-status-of
(fn
(events)
(reduce
(fn
(st e)
(let
((t (persist/event-type e)))
(cond
((= t :created) :pending)
((= t :reserved) :reserved)
((= t :paid) :paid)
((= t :fulfilled) :fulfilled)
((= t :cancelled) :cancelled)
((= t :refunded) :refunded)
(:else st))))
:new events)))
(define
order-total-of
(fn
(events)
(let
((created (filter (fn (e) (= (persist/event-type e) :created)) events)))
(if
(empty? created)
0
(get (persist/event-data (first created)) :total)))))
(define
order-paid-amount-of
(fn
(events)
(reduce
(fn
(acc e)
(if
(= (persist/event-type e) :paid)
(+ acc (get (persist/event-data e) :amount))
acc))
0
events)))
(define
order-refunded-amount-of
(fn
(events)
(reduce
(fn
(acc e)
(if
(= (persist/event-type e) :refunded)
(+ acc (get (persist/event-data e) :amount))
acc))
0
events)))
;; Net settled = paid - refunded. Reconciliation compares this to the order
;; total, but only once a payment exists.
(define
order-recon-of
(fn
(events)
(let
((net (- (order-paid-amount-of events) (order-refunded-amount-of events)))
(total (order-total-of events))
(has-paid (some (fn (e) (= (persist/event-type e) :paid)) events)))
(cond
((not has-paid) :unpaid)
((= net total) :ok)
((< net total) :underpaid)
(:else :overpaid)))))
;; --- backend-level helpers ---
(define
order-status
(fn (b order-id) (order-status-of (order-events b order-id))))
(define
order-total
(fn (b order-id) (order-total-of (order-events b order-id))))
(define
order-paid
(fn (b order-id) (order-paid-amount-of (order-events b order-id))))
(define
order-recon
(fn (b order-id) (order-recon-of (order-events b order-id))))
(define order-ids (fn (b) (persist/backend-streams b)))
;; Streams whose net payment does not match the order total (true mismatches,
;; excluding orders that are simply not yet paid).
(define
ledger-mismatches
(fn
(b)
(filter
(fn
(s)
(let
((r (order-recon-of (persist/read b s))))
(or (= r :underpaid) (= r :overpaid))))
(persist/backend-streams b))))

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;; lib/commerce/nettax.sx — discount-aware tax (alternative policy).
;;
;; price.sx / quote.sx tax the GROSS per-line amounts (discount reduces payable
;; but not the tax base). This module is the alternative explicit policy: tax the
;; NET (post-discount) base. The basket-level discount is allocated across lines
;; in proportion to each line's extended price, with a deterministic
;; largest-remainder pass so per-line shares sum EXACTLY to the discount; tax is
;; then charged on each line's net at its class rate.
;;
;; Both policies are reproducible from (ctx, cart, ruleset, exclusions); pick the
;; one the jurisdiction requires. cart-quote-net mirrors cart-quote's shape.
(define ct-sum (fn (xs) (reduce (fn (a x) (+ a x)) 0 xs)))
;; Add 1 to the first `rem` elements (deterministic remainder distribution).
(define
ct-add-rem
(fn
(xs rem)
(cond
((empty? xs) (list))
((> rem 0)
(cons
(+ (first xs) 1)
(ct-add-rem (rest xs) (- rem 1))))
(:else xs))))
;; Per-line discount allocation (parallel to cart), summing exactly to
;; total-discount, proportional to line-extended share.
(define
allocate-discount
(fn
(cat cart total-discount)
(let
((sub (cart-subtotal cat cart)))
(if
(= sub 0)
(map (fn (l) 0) cart)
(let
((floors (map (fn (l) (quotient (* total-discount (line-extended cat l)) sub)) cart)))
(ct-add-rem floors (- total-discount (ct-sum floors))))))))
;; Tax on one line's net (extended - allocated discount), clamped at 0.
(define
net-line-tax
(fn
(ctx line alloc)
(let
((cat (ctx-catalog ctx)))
(let
((net (- (line-extended cat line) alloc)))
(apply-bps
(if (< net 0) 0 net)
(rate-bps
(get ctx :tax-rules)
(get ctx :jurisdiction)
(catalog-class cat (line-sku line))
(get ctx :customer)))))))
(define
net-tax
(fn
(ctx cart allocations)
(ct-sum
(map (fn (line alloc) (net-line-tax ctx line alloc)) cart allocations))))
;; Discount-aware quote: tax computed on the net (post-discount) base.
(define
cart-quote-net
(fn
(ctx cart ruleset exclusions)
(let
((cat (ctx-catalog ctx)))
(let
((sub (cart-subtotal cat cart))
(disc (best-promo-discount ctx cart ruleset exclusions))
(codes (best-promo-codes ctx cart ruleset exclusions)))
(let
((tax (net-tax ctx cart (allocate-discount cat cart disc))))
{:codes codes :subtotal sub :discount disc :total (+ (- sub disc) tax) :tax tax})))))

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;; lib/commerce/order.sx — order lifecycle as a durable flow-on-sx flow.
;;
;; The lifecycle (reserve -> await payment -> fulfil) is a Scheme flow running
;; in the flow-on-sx guest (lib/flow). The flow is PURE ORCHESTRATION: it
;; carries only the order-id and enforces step ordering + the suspension at the
;; payment IO boundary. All IO/state lives in SX: the SX driver here services
;; each flow request by appending to the persist ledger (ledger.sx).
;;
;; reserve -> SX appends :reserved, resumes (synchronous host effect)
;; payment -> flow stays SUSPENDED until the SumUp webhook resumes it
;; fulfil -> SX appends :fulfilled, resumes (synchronous host effect)
;;
;; Durability: the flow's replay log is plain data (flow-store-export), so a
;; suspended order survives a process restart — order-flow-restart! simulates
;; that entirely Scheme-side. Idempotency: order-settle! only resumes a flow
;; still waiting on payment, so a replayed webhook is a no-op at the flow level,
;; and order-pay is idempotent at the ledger level.
;; The flow definition (Scheme source). oid is in scope throughout the begin.
(define
order-flow-src
"(defflow order-lifecycle (lambda (oid) (begin (request (quote reserve) oid) (request (quote payment) oid) (request (quote fulfil) oid))))")
;; Build a flow env with the order flow registered. Never returns the env from
;; an eval boundary (the env is large/cyclic — serializing it hangs).
(define
order-make-env
(fn
()
(let
((env (flow-make-env)))
(begin (flow-run-in env order-flow-src) env))))
;; --- thin Scheme bridge (string-interpolated flow ops) ---
(define
order-flow-start
(fn
(env oid)
(flow-run-in env (str "(flow/start order-lifecycle \"" oid "\")"))))
(define
order-flow-resume
(fn
(env id sym)
(flow-run-in env (str "(flow/resume " id " (quote " sym "))"))))
(define
order-flow-status
(fn (env id) (flow-run-in env (str "(flow/status " id ")"))))
(define
order-flow-result
(fn (env id) (flow-run-in env (str "(flow/result " id ")"))))
;; The request kind the flow with this id is waiting on, or nil if it is not
;; suspended on a host request (done / cancelled / unknown).
(define
order-flow-waiting
(fn
(env id)
(let
((reqs (flow-run-in env "(flow-host-requests)")))
(let
((mine (filter (fn (r) (= (first r) id)) reqs)))
(if (empty? mine) nil (nth (first mine) 1))))))
;; Id out of a (flow-suspended id tag) start/resume result.
(define order-susp-id (fn (susp) (nth susp 1)))
;; --- high-level lifecycle (flow + ledger composed) ---
;; Create the order, start the flow, service the reserve step, and leave the
;; flow suspended at payment. Returns the flow id (needed to settle later).
(define
order-begin!
(fn
(env b oid at quote)
(begin
(order-create b oid at quote)
(let
((id (order-susp-id (order-flow-start env oid))))
(begin
(order-reserve b oid (+ at 1) {})
(order-flow-resume env id :reserved)
id)))))
;; Settle a payment: record it, resume the flow past payment, service fulfil.
;; Idempotent — only acts when the flow is still waiting on payment, so a
;; replayed webhook returns :already-settled without double-charging.
(define
order-settle!
(fn
(env b id oid ref at amount)
(if
(= (order-flow-waiting env id) "payment")
(begin
(order-pay b oid ref at amount)
(order-flow-resume env id :paid)
(order-fulfil b oid (+ at 1) {})
(order-flow-resume env id :fulfilled)
:settled)
:already-settled)))
;; Simulate a process restart: export the flow store, reset the runtime, reload
;; the flow definition, reimport the store. Done entirely Scheme-side so the
;; (large) store is never marshalled across the boundary. The persist ledger is
;; a separate store and is unaffected. Suspended flows resume afterwards.
(define
order-flow-restart!
(fn
(env)
(flow-run-in
env
(str
"(begin (define _saved (flow-store-export)) "
flow-reset-src
" "
order-flow-src
" (flow-store-import! _saved) #t)"))))

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;; lib/commerce/payment.sx — provider-neutral payment-request envelope.
;;
;; The order flow (order.sx) suspends on `(request 'payment oid)` — it carries
;; ONLY the order-id and calls no provider. This layer materialises, at the IO
;; edge, the envelope a provider adapter needs to initiate payment:
;;
;; {:order oid :amount <ledger total> :currency C :return-url U}
;;
;; amount comes from the ledger (the :created quote total); currency + return-url
;; are host/provider config (legitimately host-supplied). The engine stays
;; vendor-agnostic: SumUp/Stripe/etc. adapters consume this envelope, and
;; order-settle!(ref, amount) is the vendor-neutral resume seam. No provider
;; SDK, HTTP, or webhook parsing lives here — that is the orders service's job.
(define payment-request (fn (b oid currency return-url) {:order oid :amount (order-total b oid) :return-url return-url :currency currency}))
(define payment-request-order (fn (pr) (get pr :order)))
(define payment-request-amount (fn (pr) (get pr :amount)))
(define payment-request-currency (fn (pr) (get pr :currency)))
(define payment-request-return-url (fn (pr) (get pr :return-url)))
;; A Scheme string carried as a flow payload round-trips back to SX wrapped as
;; {:scm-string "..."}; unwrap it to the bare order-id.
(define
scm->string
(fn
(v)
(if (and (dict? v) (has-key? v :scm-string)) (get v :scm-string) v)))
;; Host poller seam: every order currently suspended awaiting payment, each with
;; its envelope. A provider adapter iterates these, initiates payment, and later
;; calls order-settle! when the webhook arrives. Needs the flow env.
(define
pending-payments
(fn
(env b currency return-url)
(let
((reqs (flow-run-in env "(flow-host-requests)")))
(map
(fn (r) {:id (first r) :request (payment-request b (scm->string (nth r 2)) currency return-url)})
(filter (fn (r) (= (nth r 1) "payment")) reqs)))))

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;; lib/commerce/price.sx — deterministic subtotal + jurisdiction-relational tax.
;;
;; A pricing context bundles the inputs that make a total reproducible:
;; {:catalog CAT :tax-rules RULES :jurisdiction J :customer C}
;; Same context + same cart => identical total, every run.
;;
;; Tax is NOT a hardcoded VAT rate. Rules are facts indexed by
;; (jurisdiction, product-class, customer-class) -> rate-bps
;; where rate-bps is an integer in basis points (2000 = 20%). taxo queries
;; them multidirectionally. Money stays in integer minor units; rounding is
;; half-up per line via integer arithmetic only — never floats.
(define
make-pricing-context
(fn (catalog tax-rules jurisdiction customer) {:customer customer :jurisdiction jurisdiction :catalog catalog :tax-rules tax-rules}))
(define ctx-catalog (fn (ctx) (get ctx :catalog)))
;; --- unit + line pricing ---
;; Variant delta, defaulting to 0 when the (sku,variant) has no variant fact.
(define
variant-delta
(fn
(cat sku variant)
(let
((rs (run 1 d (varianto cat sku variant d))))
(if (empty? rs) 0 (first rs)))))
;; Effective unit price = base price + variant delta. nil if sku unknown.
(define
line-unit-price
(fn
(cat sku variant)
(let
((base (catalog-price cat sku)))
(if (nil? base) nil (+ base (variant-delta cat sku variant))))))
;; Extended (line) price = unit price * quantity.
(define
line-extended
(fn
(cat line)
(*
(line-unit-price cat (line-sku line) (line-variant line))
(line-qty line))))
(define
cart-subtotal
(fn
(cat cart)
(reduce (fn (acc l) (+ acc (line-extended cat l))) 0 cart)))
;; --- tax (jurisdiction-relational) ---
;; rules: (list (list jurisdiction class customer bps) ...)
(define
taxo
(fn
(rules juris class cust bps)
(membero (list juris class cust bps) rules)))
;; Deterministic rate lookup; 0 when no rule matches.
(define
rate-bps
(fn
(rules juris class cust)
(let
((rs (run 1 b (taxo rules juris class cust b))))
(if (empty? rs) 0 (first rs)))))
;; Apply a basis-point rate to an integer amount, rounding half up.
(define
apply-bps
(fn (amount bps) (quotient (+ (* amount bps) 5000) 10000)))
(define
line-tax
(fn
(ctx line)
(let
((cat (ctx-catalog ctx)))
(let
((class (catalog-class cat (line-sku line))))
(apply-bps
(line-extended cat line)
(rate-bps
(get ctx :tax-rules)
(get ctx :jurisdiction)
class
(get ctx :customer)))))))
(define
cart-tax
(fn
(ctx cart)
(reduce (fn (acc l) (+ acc (line-tax ctx l))) 0 cart)))
;; --- total ---
;; Returns {:subtotal :discounts :tax :total}. discounts is 0 until Phase 2.
(define
cart-total
(fn
(ctx cart)
(let
((cat (ctx-catalog ctx)))
(let
((sub (cart-subtotal cat cart)) (tax (cart-tax ctx cart)))
{:subtotal sub :discounts 0 :total (+ sub tax) :tax tax}))))

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;; lib/commerce/promo.sx — promotions as relations over the cart + catalog.
;;
;; A promo is a tagged tuple; the second field is always its code:
;; (:percent code class pct-bps) pct-bps off every line of product-class
;; (:fixed code threshold amount) amount off when subtotal >= threshold
;; (:bundle code sku n) every nth unit of sku is free
;; (:member code class pct-bps) like :percent, members only
;;
;; A ruleset is a list of promo tuples. The discount a promo yields on a
;; given cart is a pure integer computation (minor units); the *enumeration*
;; of which promos apply is relational, so promo-applieso runs forward
;; ("which codes apply and for how much?") and backward ("which code yields
;; this discount?"). Stacking precedence is a separate layer (stack.sx).
(define promo-kind (fn (p) (nth p 0)))
(define promo-code (fn (p) (nth p 1)))
;; Extended price of all lines whose sku is in product-class `class`.
(define
class-extended
(fn
(ctx cart class)
(let
((cat (ctx-catalog ctx)))
(reduce
(fn
(acc l)
(if
(= (catalog-class cat (line-sku l)) class)
(+ acc (line-extended cat l))
acc))
0
cart))))
(define
sku-qty
(fn
(cart sku)
(reduce
(fn (acc l) (if (= (line-sku l) sku) (+ acc (line-qty l)) acc))
0
cart)))
;; --- per-type discount amounts (pure, integer minor units) ---
(define
percent-amount
(fn
(ctx cart p)
(apply-bps
(class-extended ctx cart (nth p 2))
(nth p 3))))
(define
fixed-amount
(fn
(ctx cart p)
(let
((sub (cart-subtotal (ctx-catalog ctx) cart)))
(if
(>= sub (nth p 2))
(min (nth p 3) sub)
0))))
(define
bundle-amount
(fn
(ctx cart p)
(let
((sku (nth p 2)) (n (nth p 3)))
(let
((free (quotient (sku-qty cart sku) n)))
(* free (catalog-price (ctx-catalog ctx) sku))))))
(define
member-amount
(fn
(ctx cart p)
(if
(= (get ctx :customer) :member)
(apply-bps
(class-extended ctx cart (nth p 2))
(nth p 3))
0)))
;; Discount this promo yields on this cart (0 if it does not apply).
(define
promo-amount
(fn
(ctx cart p)
(let
((k (promo-kind p)))
(cond
((= k :percent) (percent-amount ctx cart p))
((= k :fixed) (fixed-amount ctx cart p))
((= k :bundle) (bundle-amount ctx cart p))
((= k :member) (member-amount ctx cart p))
(:else 0)))))
;; --- relational enumeration ---
;; (code, amount) for every promo in the ruleset (amount may be 0).
(define
promo-discounto
(fn
(ctx cart ruleset code amount)
(fresh
(p)
(membero p ruleset)
(project
(p)
(== code (promo-code p))
(== amount (promo-amount ctx cart p))))))
;; (code, amount) restricted to promos that actually apply (amount > 0).
(define
promo-applieso
(fn
(ctx cart ruleset code amount)
(fresh
(p)
(membero p ruleset)
(project
(p)
(if
(> (promo-amount ctx cart p) 0)
(mk-conj
(== code (promo-code p))
(== amount (promo-amount ctx cart p)))
fail)))))
;; --- deterministic helpers ---
;; List of (list code amount) for applicable promos, in ruleset order.
(define
applicable-promos
(fn
(ctx cart ruleset)
(run*
pair
(fresh
(code amount)
(promo-applieso ctx cart ruleset code amount)
(== pair (list code amount))))))
;; Discount for one code (0 if absent / inapplicable).
(define
promo-amount-for
(fn
(ctx cart ruleset code)
(let
((rs (run 1 a (promo-applieso ctx cart ruleset code a))))
(if (empty? rs) 0 (first rs)))))

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;; lib/commerce/quote.sx — the final priced quote: price + promo + stacking.
;;
;; A quote is the deterministic composition of the pricing pipeline for a
;; (context, cart, ruleset, exclusions) tuple:
;; {:subtotal S :discount D :tax T :total (S - D + T) :codes (...)}
;;
;; Tax policy (explicit, for the determinism contract): tax is computed on the
;; GROSS per-line amounts (pre-discount), via price.sx cart-tax. The best
;; promo stacking reduces the payable total but not the tax base. Same inputs
;; always yield the same quote — this is the value the order flow carries.
(define
cart-quote
(fn
(ctx cart ruleset exclusions)
(let
((cat (ctx-catalog ctx)))
(let
((sub (cart-subtotal cat cart))
(disc (best-promo-discount ctx cart ruleset exclusions))
(tax (cart-tax ctx cart))
(codes (best-promo-codes ctx cart ruleset exclusions)))
{:codes codes :subtotal sub :discount disc :total (+ (- sub disc) tax) :tax tax}))))
(define quote-subtotal (fn (q) (get q :subtotal)))
(define quote-discount (fn (q) (get q :discount)))
(define quote-tax (fn (q) (get q :tax)))
(define quote-total (fn (q) (get q :total)))
(define quote-codes (fn (q) (get q :codes)))
;; Session-level convenience (a session is {:ctx :cart}).
(define
session-quote
(fn
(sess ruleset exclusions)
(cart-quote (get sess :ctx) (get sess :cart) ruleset exclusions)))

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;; lib/commerce/recon.sx — reconciliation as relational queries over the ledger.
;;
;; The ledger (ledger.sx) is the source of truth; reconciliation projects it
;; into per-order summary tuples and then asks miniKanren questions about them.
;; "Which orders are overpaid?" / "which order settled to net N?" are backward
;; queries (run*) over the same relation, not separate code paths.
;;
;; A summary tuple is positional:
;; (order-stream total paid refunded net status)
;; net = paid - refunded; status = :unpaid|:ok|:underpaid|:overpaid.
(define
order-summary
(fn
(b stream)
(let
((events (persist/read b stream)))
(let
((total (order-total-of events))
(paid (order-paid-amount-of events))
(refunded (order-refunded-amount-of events)))
(list
stream
total
paid
refunded
(- paid refunded)
(order-recon-of events))))))
(define
ledger-summaries
(fn (b) (map (fn (s) (order-summary b s)) (persist/backend-streams b))))
;; --- relations over the summary set ---
(define
summaryo
(fn
(summaries id total paid refunded net status)
(membero (list id total paid refunded net status) summaries)))
(define
recon-statuso
(fn
(summaries id status)
(fresh (t p r n) (summaryo summaries id t p r n status))))
(define
neto
(fn
(summaries id net)
(fresh (t p r status) (summaryo summaries id t p r net status))))
;; A mismatch is any order whose money does not reconcile (over or under).
(define
mismatcho
(fn
(summaries id)
(fresh
(status)
(recon-statuso summaries id status)
(conde ((== status :underpaid)) ((== status :overpaid))))))
;; --- deterministic query helpers (run* over the live ledger) ---
(define
orders-with-status
(fn (b status) (run* id (recon-statuso (ledger-summaries b) id status))))
(define overpaid-orders (fn (b) (orders-with-status b :overpaid)))
(define underpaid-orders (fn (b) (orders-with-status b :underpaid)))
(define settled-orders (fn (b) (orders-with-status b :ok)))
(define unpaid-orders (fn (b) (orders-with-status b :unpaid)))
(define
mismatched-orders
(fn (b) (run* id (mismatcho (ledger-summaries b) id))))
;; Backward: which order(s) settled to a given net amount?
(define
orders-with-net
(fn (b net) (run* id (neto (ledger-summaries b) id net))))
;; Total signed discrepancy across the ledger (net - total over paid orders);
;; 0 when every settled order reconciles exactly.
(define
ledger-discrepancy
(fn
(b)
(reduce
(fn
(acc s)
(let
((status (nth s 5)))
(if
(= status :unpaid)
acc
(+ acc (- (nth s 4) (nth s 1))))))
0
(ledger-summaries b))))

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;; lib/commerce/refund.sx — refund lifecycle as a second flow-on-sx flow.
;;
;; A refund is request → approve → settle, with TWO genuine suspension points:
;; approval (a human/policy decision) and settlement (the provider issuing the
;; refund). Like order.sx the flow is pure orchestration carrying only the
;; order-id; the SX driver does all ledger IO and reuses order.sx's generic flow
;; helpers (order-flow-waiting/-resume/-status, order-susp-id).
;;
;; refund-begin! → ledger :refund-requested, flow suspends at 'approve
;; refund-approve! → resume past approval, flow suspends at 'settle
;; refund-settle! → ledger :refunded (idempotent), flow completes
;; refund-reject! → ledger :refund-rejected, flow cancelled
;;
;; Only :refunded moves the books (recon.sx), so a requested-but-unsettled or
;; rejected refund leaves reconciliation unchanged.
(define
refund-flow-src
"(defflow refund-lifecycle (lambda (oid) (begin (request (quote approve) oid) (request (quote settle) oid))))")
(define
refund-make-env
(fn
()
(let
((env (flow-make-env)))
(begin (flow-run-in env refund-flow-src) env))))
;; Register the refund flow into an existing (e.g. order) env.
(define
refund-flow-load!
(fn (env) (begin (flow-run-in env refund-flow-src) env)))
(define
refund-flow-start
(fn
(env oid)
(flow-run-in env (str "(flow/start refund-lifecycle \"" oid "\")"))))
;; --- ledger writes ---
(define
refund-request
(fn
(b oid ref at amount)
(persist/append-once
b
(order-stream oid)
(str "refund-req/" ref)
:refund-requested at
{:amount amount :ref ref})))
;; --- lifecycle ---
;; Open a refund: record the request, start the flow, suspend at approval.
(define
refund-begin!
(fn
(env b oid ref at amount)
(begin
(refund-request b oid ref at amount)
(order-susp-id (refund-flow-start env oid)))))
(define
refund-approve!
(fn
(env id)
(if
(= (order-flow-waiting env id) "approve")
(begin (order-flow-resume env id :approved) :approved)
:not-pending-approval)))
(define
refund-reject!
(fn
(env b oid id at reason)
(if
(= (order-flow-waiting env id) "approve")
(begin
(persist/append b (order-stream oid) :refund-rejected at {:reason reason})
(flow-run-in env (str "(flow/cancel " id ")"))
:rejected)
:not-pending-approval)))
;; Settle (provider issued the refund): idempotent — only acts while waiting on
;; settle, so a replayed provider callback returns :already-settled.
(define
refund-settle!
(fn
(env b id oid ref at amount)
(if
(= (order-flow-waiting env id) "settle")
(begin
(order-refund b oid ref at amount)
(order-flow-resume env id :settled)
:settled)
:already-settled)))

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{
"suites": {
"catalog": {"pass": 16, "fail": 0},
"cart": {"pass": 18, "fail": 0},
"price": {"pass": 20, "fail": 0},
"api": {"pass": 12, "fail": 0},
"promo": {"pass": 17, "fail": 0},
"stack": {"pass": 16, "fail": 0},
"quote": {"pass": 13, "fail": 0},
"ledger": {"pass": 20, "fail": 0},
"order": {"pass": 22, "fail": 0},
"recon": {"pass": 20, "fail": 0},
"federation": {"pass": 12, "fail": 0},
"attribution": {"pass": 16, "fail": 0},
"payment": {"pass": 7, "fail": 0},
"window": {"pass": 19, "fail": 0},
"nettax": {"pass": 11, "fail": 0},
"stock": {"pass": 19, "fail": 0},
"refund": {"pass": 20, "fail": 0},
"integration": {"pass": 19, "fail": 0}
},
"total_pass": 297,
"total_fail": 0,
"total": 297
}

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# commerce Conformance Scoreboard
_Generated by `lib/commerce/conformance.sh`_
| Suite | Pass | Fail | Total |
|-------|-----:|-----:|------:|
| catalog | 16 | 0 | 16 |
| cart | 18 | 0 | 18 |
| price | 20 | 0 | 20 |
| api | 12 | 0 | 12 |
| promo | 17 | 0 | 17 |
| stack | 16 | 0 | 16 |
| quote | 13 | 0 | 13 |
| ledger | 20 | 0 | 20 |
| order | 22 | 0 | 22 |
| recon | 20 | 0 | 20 |
| federation | 12 | 0 | 12 |
| attribution | 16 | 0 | 16 |
| payment | 7 | 0 | 7 |
| window | 19 | 0 | 19 |
| nettax | 11 | 0 | 11 |
| stock | 19 | 0 | 19 |
| refund | 20 | 0 | 20 |
| integration | 19 | 0 | 19 |
| **Total** | **297** | **0** | **297** |

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;; lib/commerce/stack.sx — promotion stacking precedence + best price.
;;
;; Per the miniKanren design rule, precedence is NOT encoded inside the promo
;; rules. promo.sx enumerates which promos apply; this layer enumerates which
;; *combinations* are legal and selects the best one by an explicit cost
;; function (max total discount = min price).
;;
;; Exclusivity is a list of unordered code pairs that may not both apply:
;; exclusions = (list (list code-a code-b) ...)
;; A stacking is a subset of applicable (code amount) pairs containing no
;; excluded pair. valid-stackings enumerates them; best-stacking is the
;; deterministic selection layer; stacking-by-totalo is the backward query
;; ("which legal stacking yields this total discount?").
(define
excluded-pair?
(fn
(exclusions a b)
(some
(fn
(p)
(or
(and (= (first p) a) (= (nth p 1) b))
(and (= (first p) b) (= (nth p 1) a))))
exclusions)))
;; True when no two distinct codes in the list are mutually excluded.
(define
compatible?
(fn
(exclusions codes)
(every?
(fn
(a)
(every?
(fn (b) (or (= a b) (not (excluded-pair? exclusions a b))))
codes))
codes)))
;; All subsets of xs, preserving element order. 2^n entries.
(define
powerset
(fn
(xs)
(if
(empty? xs)
(list (list))
(let
((r (powerset (cdr xs))))
(append r (map (fn (s) (cons (first xs) s)) r))))))
(define stacking-codes (fn (st) (map first st)))
(define
stacking-total
(fn
(st)
(reduce (fn (acc pair) (+ acc (nth pair 1))) 0 st)))
;; Every legal stacking of the applicable (code amount) pairs.
(define
valid-stackings
(fn
(exclusions applicable)
(filter
(fn (st) (compatible? exclusions (stacking-codes st)))
(powerset applicable))))
;; Deterministic selection: the legal stacking with the greatest total
;; discount; ties keep the earlier (stable) candidate, so the result is a
;; reproducible function of (exclusions, applicable).
(define
best-stacking
(fn
(exclusions applicable)
(reduce
(fn
(best st)
(if (> (stacking-total st) (stacking-total best)) st best))
(list)
(valid-stackings exclusions applicable))))
(define
best-discount
(fn
(exclusions applicable)
(stacking-total (best-stacking exclusions applicable))))
(define
best-codes
(fn
(exclusions applicable)
(stacking-codes (best-stacking exclusions applicable))))
;; Backward query: legal stackings (as code lists) whose total discount = D.
(define
stacking-by-totalo
(fn
(stackings codes total)
(fresh
(st)
(membero st stackings)
(project
(st)
(mk-conj
(== codes (stacking-codes st))
(== total (stacking-total st)))))))
;; --- top-level entry: best discount for a cart under a ruleset ---
(define
best-promo-discount
(fn
(ctx cart ruleset exclusions)
(best-discount exclusions (applicable-promos ctx cart ruleset))))
(define
best-promo-codes
(fn
(ctx cart ruleset exclusions)
(best-codes exclusions (applicable-promos ctx cart ruleset))))

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;; lib/commerce/stock.sx — stock-constrained reservation.
;;
;; Reservation is a precondition the host checks BEFORE order-begin! (validate →
;; begin), so the order flow stays pure orchestration. Availability is read
;; relationally from the catalog stock facts (catalog.sx stocko); a stock view
;; subtracts already-reserved quantities so concurrent orders can't over-reserve.
;;
;; can-reserve? cat cart — every line fits available stock
;; reservation-shortfalls cat cart — the lines that do not, with detail
;; effective-available cat reservations … — availability net of reservations
;; sufficient-stocko cat sku variant qty — relational "can supply qty?" query
;; Deterministic on-hand stock for a (sku,variant); 0 if absent.
(define
available-stock
(fn
(cat sku variant)
(let
((rs (run 1 q (stocko cat sku variant q))))
(if (empty? rs) 0 (first rs)))))
;; Units a line cannot fulfil from on-hand stock (0 if it fits).
(define
line-shortfall
(fn
(cat line)
(let
((short (- (line-qty line) (available-stock cat (line-sku line) (line-variant line)))))
(if (< short 0) 0 short))))
(define
line-reservable?
(fn (cat line) (= (line-shortfall cat line) 0)))
;; Lines that cannot be fully reserved, each with requested/available/short.
(define
reservation-shortfalls
(fn
(cat cart)
(reduce
(fn
(acc line)
(let
((short (line-shortfall cat line)))
(if (> short 0) (append acc (list {:requested (line-qty line) :available (available-stock cat (line-sku line) (line-variant line)) :sku (line-sku line) :variant (line-variant line) :short short})) acc)))
(list)
cart)))
(define
can-reserve?
(fn (cat cart) (empty? (reservation-shortfalls cat cart))))
;; Validate → reject; the host gates order-begin! on this.
(define
reserve-check
(fn (cat cart) (if (can-reserve? cat cart) :ok {:shortfalls (reservation-shortfalls cat cart) :rejected :insufficient-stock})))
;; --- reservation view (concurrent-safety) ---
;; reservations: list of (sku variant qty) already held.
(define
reserved-qty
(fn
(reservations sku variant)
(reduce
(fn
(acc r)
(if
(and (= (first r) sku) (= (nth r 1) variant))
(+ acc (nth r 2))
acc))
0
reservations)))
;; On-hand minus already-reserved (clamped at 0).
(define
effective-available
(fn
(cat reservations sku variant)
(let
((eff (- (available-stock cat sku variant) (reserved-qty reservations sku variant))))
(if (< eff 0) 0 eff))))
;; Can a line be reserved given existing reservations?
(define
line-reservable-with?
(fn
(cat reservations line)
(<=
(line-qty line)
(effective-available
cat
reservations
(line-sku line)
(line-variant line)))))
;; --- relational availability query (the showcase) ---
;; Succeeds when on-hand stock for (sku,variant) covers qty. Multidirectional
;; over the stock facts: "which variants of widget can supply 5?" is a backward
;; query.
(define
sufficient-stocko
(fn
(cat sku variant qty)
(fresh (avail) (stocko cat sku variant avail) (lteo-i qty avail))))

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;; lib/commerce/tests/api.sx — public commerce session surface.
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define
acat
(make-catalog
(list
(list "widget" 1000 :standard)
(list "book" 800 :zero-rated))
(list (list "widget" :small -200))
(list)))
(define
arules
(list
(list :uk :standard :guest 2000)
(list :uk :zero-rated :guest 0)))
(define actx (make-pricing-context acat arules :uk :guest))
(define sess0 (commerce-session actx))
;; --- empty session ---
(commerce-test "new-session-empty" (commerce-cart sess0) empty-cart)
(commerce-test "new-count" (commerce-count sess0) 0)
(commerce-test "new-total" (commerce-total sess0) {:subtotal 0 :discounts 0 :total 0 :tax 0})
;; --- add + total ---
(define
sess1
(commerce-add
(commerce-add sess0 "widget" :small 2)
"book"
:none 1))
(commerce-test "add-count" (commerce-count sess1) 3)
(commerce-test
"add-lines"
(commerce-lines sess1)
(list (list "widget" :small 2) (list "book" :none 1)))
(commerce-test "add-total" (commerce-total sess1) {:subtotal 2400 :discounts 0 :total 2720 :tax 320})
;; --- mutate ---
(commerce-test
"set-qty"
(commerce-lines (commerce-set-qty sess1 "widget" :small 1))
(list (list "widget" :small 1) (list "book" :none 1)))
(commerce-test
"remove"
(commerce-lines (commerce-remove sess1 "book" :none))
(list (list "widget" :small 2)))
;; --- validation ---
(commerce-test "can-add-yes" (commerce-can-add? sess0 "widget") true)
(commerce-test "can-add-no" (commerce-can-add? sess0 "ghost") false)
;; --- audit breakdown ---
(commerce-test
"explain"
(commerce-explain sess1)
(list {:sku "widget" :unit 800 :qty 2 :variant :small :extended 1600 :tax 320} {:sku "book" :unit 800 :qty 1 :variant :none :extended 800 :tax 0}))
;; --- checkout stub ---
(commerce-test
"checkout-stub"
(get (commerce-checkout sess1) :status)
:not-implemented)

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;; lib/commerce/tests/attribution.sx — line-level discount attribution.
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define
pcat
(make-catalog
(list
(list "widget" 1000 :standard)
(list "gizmo" 2000 :standard)
(list "book" 800 :zero-rated)
(list "tea" 1000 :reduced))
(list)
(list)))
(define gctx (make-pricing-context pcat (list) :uk :guest))
(define mctx (make-pricing-context pcat (list) :uk :member))
(define
cart
(list
(list "widget" :none 2)
(list "gizmo" :none 1)
(list "book" :none 1)
(list "tea" :none 6)))
(define
ruleset
(list
(list :percent "TEN" :standard 1000)
(list :percent "TWENTY" :standard 2000)
(list :bundle "B3T" "tea" 3)
(list :fixed "FIVE" 0 500)
(list :member "MEM" :standard 1500)))
(define w-line (list "widget" :none 2))
(define t-line (list "tea" :none 6))
(define bk-line (list "book" :none 1))
;; --- scope helpers ---
(commerce-test
"class-lines-standard"
(class-lines gctx cart :standard)
(list (list "widget" :none 2) (list "gizmo" :none 1)))
(commerce-test
"promo-lines-bundle"
(promo-lines gctx cart (list :bundle "B3T" "tea" 3))
(list (list "tea" :none 6)))
(commerce-test
"promo-lines-fixed-none"
(promo-lines gctx cart (list :fixed "FIVE" 0 500))
(list))
;; --- forward: which lines does a code touch? ---
(commerce-test
"lines-for-ten"
(lines-for-code gctx cart ruleset "TEN")
(list (list "widget" :none 2) (list "gizmo" :none 1)))
(commerce-test
"lines-for-bundle"
(lines-for-code gctx cart ruleset "B3T")
(list (list "tea" :none 6)))
(commerce-test
"lines-for-fixed-empty"
(lines-for-code gctx cart ruleset "FIVE")
(list))
(commerce-test
"lines-for-mem-guest-empty"
(lines-for-code gctx cart ruleset "MEM")
(list))
;; --- backward: which codes touch this line? (the showcase) ---
(commerce-test
"codes-for-widget-guest"
(codes-for-line gctx cart ruleset w-line)
(list "TEN" "TWENTY"))
(commerce-test
"codes-for-tea"
(codes-for-line gctx cart ruleset t-line)
(list "B3T"))
(commerce-test
"codes-for-book-none"
(codes-for-line gctx cart ruleset bk-line)
(list))
;; member sees the member rate too
(commerce-test
"codes-for-widget-member"
(codes-for-line mctx cart ruleset w-line)
(list "TEN" "TWENTY" "MEM"))
(commerce-test
"lines-for-mem-member"
(lines-for-code mctx cart ruleset "MEM")
(list (list "widget" :none 2) (list "gizmo" :none 1)))
;; --- predicate ---
(commerce-test
"touched-yes"
(line-touched-by? gctx cart ruleset "TEN" w-line)
true)
(commerce-test
"touched-no-wrong-class"
(line-touched-by? gctx cart ruleset "B3T" w-line)
false)
(commerce-test
"touched-no-guest-mem"
(line-touched-by? gctx cart ruleset "MEM" w-line)
false)
;; --- order-level (fixed) codes ---
(commerce-test
"order-level"
(order-level-codes gctx cart ruleset)
(list "FIVE"))

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;; lib/commerce/tests/cart.sx — cart structure + line operations.
;; Uses (commerce-test name got expected) provided by conformance.sh.
;; --- add ---
(commerce-test
"add-to-empty"
(cart-add empty-cart "widget" :small 2)
(list (list "widget" :small 2)))
(commerce-test
"add-merges-same-line"
(cart-add
(cart-add empty-cart "widget" :small 2)
"widget"
:small 3)
(list (list "widget" :small 5)))
(commerce-test
"add-different-variant-separate"
(cart-add
(cart-add empty-cart "widget" :small 2)
"widget"
:large 1)
(list (list "widget" :small 2) (list "widget" :large 1)))
(commerce-test
"add-different-sku-separate"
(cart-add
(cart-add empty-cart "widget" :small 2)
"gadget"
:std 1)
(list (list "widget" :small 2) (list "gadget" :std 1)))
(commerce-test
"add-preserves-order"
(cart-skus
(cart-add
(cart-add (cart-add empty-cart "a" :v 1) "b" :v 1)
"c"
:v 1))
(list "a" "b" "c"))
;; --- qty queries ---
(define
c2
(cart-add
(cart-add empty-cart "widget" :small 2)
"gadget"
:std 4))
(commerce-test "cart-qty-found" (cart-qty c2 "widget" :small) 2)
(commerce-test "cart-qty-missing" (cart-qty c2 "widget" :large) 0)
(commerce-test "cart-count" (cart-count c2) 6)
(commerce-test "cart-empty-yes" (cart-empty? empty-cart) true)
(commerce-test "cart-empty-no" (cart-empty? c2) false)
;; --- set-qty ---
(commerce-test
"set-qty-existing"
(cart-set-qty c2 "widget" :small 10)
(list (list "widget" :small 10) (list "gadget" :std 4)))
(commerce-test
"set-qty-new-line"
(cart-set-qty empty-cart "book" :std 3)
(list (list "book" :std 3)))
(commerce-test
"set-qty-zero-removes"
(cart-set-qty c2 "widget" :small 0)
(list (list "gadget" :std 4)))
;; --- remove ---
(commerce-test
"remove-line"
(cart-remove c2 "gadget" :std)
(list (list "widget" :small 2)))
(commerce-test
"remove-missing-noop"
(cart-remove c2 "nope" :std)
(list (list "widget" :small 2) (list "gadget" :std 4)))
;; --- relational view ---
(commerce-test
"cart-lineo-forward"
(run* q (cart-lineo c2 "gadget" :std q))
(list 4))
(commerce-test
"cart-lineo-sku-by-qty-backward"
(run* sk (fresh (v) (cart-lineo c2 sk v 4)))
(list "gadget"))
(commerce-test
"cart-lineo-all-skus"
(run* sk (fresh (v q) (cart-lineo c2 sk v q)))
(list "widget" "gadget"))

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;; lib/commerce/tests/catalog.sx — catalog facts + relational accessors.
;; Uses (commerce-test name got expected) provided by conformance.sh.
;; Query vars avoid the name `s` (the run-n macro binds `s` internally).
(define
cat
(make-catalog
(list
(list "widget" 1000 :standard)
(list "gadget" 2500 :standard)
(list "book" 800 :zero-rated)
(list "tea" 1000 :reduced))
(list
(list "widget" :small -200)
(list "widget" :large 500)
(list "gadget" :std 0))
(list
(list "widget" :small 5)
(list "widget" :large 0)
(list "gadget" :std 12))))
;; --- forward lookups ---
(commerce-test
"price-forward"
(run* p (priceo cat "widget" p))
(list 1000))
(commerce-test
"class-forward"
(run* c (classo cat "book" c))
(list :zero-rated))
(commerce-test
"product-forward"
(run* q (fresh (p c) (producto cat "gadget" p c) (== q (list p c))))
(list (list 2500 :standard)))
;; --- backward lookups (the showcase) ---
(commerce-test
"sku-by-price-backward"
(run* sk (priceo cat sk 1000))
(list "widget" "tea"))
(commerce-test
"sku-by-class-backward"
(run* sk (classo cat sk :standard))
(list "widget" "gadget"))
(commerce-test
"all-prices"
(run* p (fresh (sk) (priceo cat sk p)))
(list 1000 2500 800 1000))
;; --- variants + effective unit price ---
(commerce-test
"variant-delta-forward"
(run* d (varianto cat "widget" :small d))
(list -200))
(commerce-test
"unit-price-small"
(run* p (unit-priceo cat "widget" :small p))
(list 800))
(commerce-test
"unit-price-large"
(run* p (unit-priceo cat "widget" :large p))
(list 1500))
(commerce-test
"variant-by-delta-backward"
(run* v (varianto cat "widget" v -200))
(list :small))
;; --- stock ---
(commerce-test
"stock-forward"
(run* q (stocko cat "widget" :small q))
(list 5))
(commerce-test
"in-stock-skus-backward"
(run* sk (fresh (v q) (stocko cat sk v q) (lto-i 0 q)))
(list "widget" "gadget"))
;; --- deterministic helpers ---
(commerce-test "catalog-price-helper" (catalog-price cat "gadget") 2500)
(commerce-test "catalog-class-helper" (catalog-class cat "tea") :reduced)
(commerce-test "catalog-has-yes" (catalog-has? cat "book") true)
(commerce-test "catalog-has-no" (catalog-has? cat "nonesuch") false)

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;; lib/commerce/tests/federation.sx — federated catalog (out-of-scope stub).
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define
cat-a
(make-catalog
(list
(list "widget" 1000 :standard)
(list "book" 800 :zero-rated))
(list)
(list)))
(define
cat-b
(make-catalog
(list
(list "widget" 900 :standard)
(list "tea" 1200 :reduced))
(list)
(list)))
(define
cat-c
(make-catalog (list (list "widget" 1100 :standard)) (list) (list)))
(define
fed
(federation-add
(federation-add (make-federation :alpha cat-a) :beta cat-b)
:gamma cat-c))
;; --- structure ---
(commerce-test "is-stub" federation-stub? true)
(commerce-test
"instances"
(federation-instances fed)
(list :alpha :beta :gamma))
(commerce-test "product-count" (len (fed-products fed)) 5)
;; --- forward query ---
(commerce-test
"price-at-instance"
(run* p (fed-priceo fed :beta "widget" p))
(list 900))
;; --- backward queries (the showcase) ---
(commerce-test
"instances-with-widget"
(instances-with-sku fed "widget")
(list :alpha :beta :gamma))
(commerce-test
"instances-with-book"
(instances-with-sku fed "book")
(list :alpha))
(commerce-test
"instances-with-tea"
(instances-with-sku fed "tea")
(list :beta))
(commerce-test
"instance-by-price-backward"
(run* inst (fresh (c) (fed-producto fed inst "widget" 1100 c)))
(list :gamma))
;; --- offers + cheapest (deterministic selection) ---
(commerce-test
"widget-offers"
(sku-offers fed "widget")
(list
(list 1000 :alpha)
(list 900 :beta)
(list 1100 :gamma)))
(commerce-test
"cheapest-widget"
(cheapest-offer fed "widget")
(list 900 :beta))
(commerce-test
"cheapest-book"
(cheapest-offer fed "book")
(list 800 :alpha))
(commerce-test "cheapest-missing" (cheapest-offer fed "ghost") nil)

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;; lib/commerce/tests/integration.sx — end-to-end composition proof.
;; Uses (commerce-test name got expected) provided by conformance.sh.
;;
;; One narrative across every module: catalog → stock check → quote
;; (promo+stack+tax) → order flow → payment envelope → settle → recon → refund.
;; Proves the seams tie together with consistent numbers (the project's thesis:
;; minikanren pricing + flow lifecycle + persist ledger compose).
;; Builds one flow env with BOTH the order and refund flows.
(define env (order-make-env))
(define _rf (refund-flow-load! env))
(define b (persist/mem-backend))
(define
cat
(make-catalog
(list
(list "widget" 1000 :standard)
(list "book" 800 :zero-rated))
(list (list "widget" :small -200))
(list (list "widget" :small 10) (list "book" :none 5))))
(define
rules
(list
(list :uk :standard :guest 2000)
(list :uk :zero-rated :guest 0)))
(define ctx (make-pricing-context cat rules :uk :guest))
(define
ruleset
(list
(list :percent "TEN" :standard 1000)
(list :fixed "FIVE" 0 50)))
;; widget :small x2 → unit 800, extended 1600 (standard); book x1 → 800 (zero-rated)
(define
cart
(list (list "widget" :small 2) (list "book" :none 1)))
;; 1. stock gating passes (widget:small 10 >= 2)
(commerce-test "int-can-reserve" (can-reserve? cat cart) true)
;; 2. quote ties the whole pricing pipeline together
;; subtotal 2400; discount TEN 160 + FIVE 50 = 210; tax 1600@20% = 320;
;; total 2400 - 210 + 320 = 2510
(define q (cart-quote ctx cart ruleset (list)))
(commerce-test "int-quote-subtotal" (quote-subtotal q) 2400)
(commerce-test "int-quote-discount" (quote-discount q) 210)
(commerce-test "int-quote-tax" (quote-tax q) 320)
(commerce-test "int-quote-total" (quote-total q) 2510)
;; 3. attribution explains where the discount landed
(commerce-test
"int-attribution"
(codes-for-line ctx cart ruleset (list "widget" :small 2))
(list "TEN"))
(commerce-test
"int-order-level"
(order-level-codes ctx cart ruleset)
(list "FIVE"))
;; 4. order carries the quote total into the ledger; suspends at payment
(define oid "INT-1")
(define id (order-begin! env b oid 1000 q))
(commerce-test "int-order-total-from-quote" (order-total b oid) 2510)
(commerce-test "int-waiting-payment" (order-flow-waiting env id) "payment")
;; 5. the payment envelope reflects the quoted total
(commerce-test
"int-payment-envelope"
(payment-request b oid :GBP "https://shop/return")
{:order "INT-1" :amount 2510 :return-url "https://shop/return" :currency :GBP})
;; 6. settle the quoted amount → reconciles exactly
(commerce-test
"int-settled"
(order-settle! env b id oid "pay-int" 1002 2510)
:settled)
(commerce-test "int-status-fulfilled" (order-status b oid) :fulfilled)
(commerce-test "int-recon-ok" (order-recon b oid) :ok)
;; 7. partial refund via its own flow → recon moves to underpaid
(define rid (refund-begin! env b oid "rf-int" 2000 510))
(commerce-test "int-refund-approve" (refund-approve! env rid) :approved)
(commerce-test
"int-refund-settle"
(refund-settle! env b rid oid "rf-int" 2001 510)
:settled)
(commerce-test
"int-refunded-amount"
(order-refunded-amount-of (order-events b oid))
510)
(commerce-test "int-recon-after-refund" (order-recon b oid) :underpaid)
;; 8. ledger reconciliation flags the now-mismatched order
(commerce-test
"int-mismatch"
(mismatched-orders b)
(list (order-stream "INT-1")))
;; 9. distinct flow ids for the order and the refund
(commerce-test "int-distinct-flow-ids" (not (= id rid)) true)

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;; lib/commerce/tests/ledger.sx — order ledger on persist + idempotent recon.
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define q1 {:codes (list) :subtotal 1000 :discount 0 :total 1200 :tax 200})
;; --- lifecycle status projection ---
(define b1 (persist/mem-backend))
(define _c1 (order-create b1 "A1" 100 q1))
(commerce-test "status-pending" (order-status b1 "A1") :pending)
(define _r1 (order-reserve b1 "A1" 101 {:lines 2}))
(commerce-test "status-reserved" (order-status b1 "A1") :reserved)
(define _p1 (order-pay b1 "A1" "ref-1" 102 1200))
(commerce-test "status-paid" (order-status b1 "A1") :paid)
(define _f1 (order-fulfil b1 "A1" 103 {:carrier "post"}))
(commerce-test "status-fulfilled" (order-status b1 "A1") :fulfilled)
(commerce-test "total-projection" (order-total b1 "A1") 1200)
(commerce-test "paid-projection" (order-paid b1 "A1") 1200)
(commerce-test "recon-ok" (order-recon b1 "A1") :ok)
(commerce-test "event-count" (len (order-events b1 "A1")) 4)
;; --- idempotency: replayed webhook does not double-record ---
(define b2 (persist/mem-backend))
(define _c2 (order-create b2 "B1" 200 q1))
(define _p2a (order-pay b2 "B1" "sumup-9" 201 1200))
(define _p2b (order-pay b2 "B1" "sumup-9" 201 1200))
(define _p2c (order-pay b2 "B1" "sumup-9" 201 1200))
(commerce-test "idem-single-event" (len (order-events b2 "B1")) 2)
(commerce-test "idem-paid-once" (order-paid b2 "B1") 1200)
(commerce-test "idem-recon-ok" (order-recon b2 "B1") :ok)
(commerce-test "idem-same-event" (= _p2a _p2c) true)
;; --- mismatch detection ---
(define bun (persist/mem-backend))
(define _cu (order-create bun "U1" 300 q1))
(commerce-test "unpaid-recon" (order-recon bun "U1") :unpaid)
(define bup (persist/mem-backend))
(define _cp (order-create bup "U2" 300 q1))
(define _pp1 (order-pay bup "U2" "r-a" 301 1200))
(define _pp2 (order-pay bup "U2" "r-b" 302 1200))
(commerce-test "double-charge-overpaid" (order-recon bup "U2") :overpaid)
(commerce-test "double-charge-amount" (order-paid bup "U2") 2400)
(define bsh (persist/mem-backend))
(define _cs (order-create bsh "U3" 400 q1))
(define _ps (order-pay bsh "U3" "r-short" 401 1000))
(commerce-test "underpaid-recon" (order-recon bsh "U3") :underpaid)
;; --- refund (idempotent) reduces net ---
(define brf (persist/mem-backend))
(define _crf (order-create brf "R1" 500 q1))
(define _prf (order-pay brf "R1" "p-1" 501 1200))
(define _rf1 (order-refund brf "R1" "rf-1" 502 200))
(define _rf2 (order-refund brf "R1" "rf-1" 502 200))
(commerce-test "refund-idem-net" (order-recon brf "R1") :underpaid)
(commerce-test "refund-idem-events" (len (order-events brf "R1")) 3)
;; --- cross-ledger reconciliation ---
(define bL (persist/mem-backend))
(define _l1 (order-create bL "OK1" 600 q1))
(define _l1p (order-pay bL "OK1" "ok-ref" 601 1200))
(define _l2 (order-create bL "OVER1" 600 q1))
(define _l2a (order-pay bL "OVER1" "o-a" 602 1200))
(define _l2b (order-pay bL "OVER1" "o-b" 603 1200))
(define _l3 (order-create bL "UNDER1" 600 q1))
(define _l3p (order-pay bL "UNDER1" "u-ref" 604 900))
(define _l4 (order-create bL "PENDING1" 600 q1))
(commerce-test "ledger-order-count" (len (order-ids bL)) 4)
(commerce-test
"ledger-mismatches"
(sort (ledger-mismatches bL))
(sort (list (order-stream "OVER1") (order-stream "UNDER1"))))

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;; lib/commerce/tests/nettax.sx — discount-aware (net) tax policy.
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define
pcat
(make-catalog
(list
(list "widget" 1000 :standard)
(list "tea" 1000 :reduced))
(list)
(list)))
(define
rules
(list
(list :uk :standard :guest 2000)
(list :uk :reduced :guest 500)))
(define gctx (make-pricing-context pcat rules :uk :guest))
;; widget x3 = 3000 (standard), tea x6 = 6000 (reduced); subtotal 9000
(define
cart
(list (list "widget" :none 3) (list "tea" :none 6)))
(define ruleset (list (list :percent "TEN" :standard 1000)))
;; --- allocation: proportional, sums exactly to the discount ---
(commerce-test
"allocate-even"
(allocate-discount pcat cart 300)
(list 100 200))
(commerce-test
"allocate-sums-to-discount"
(ct-sum (allocate-discount pcat cart 300))
300)
;; remainder distribution: 100 over (3000,6000)/9000 = (33,66) rem 1 -> (34,66)
(commerce-test
"allocate-remainder"
(allocate-discount pcat cart 100)
(list 34 66))
(commerce-test
"allocate-remainder-sums"
(ct-sum (allocate-discount pcat cart 100))
100)
(commerce-test
"allocate-zero"
(allocate-discount pcat cart 0)
(list 0 0))
(commerce-test
"allocate-empty"
(allocate-discount pcat empty-cart 0)
(list))
;; --- net tax vs gross tax ---
;; discount = TEN 10% of standard 3000 = 300, allocated (100 200).
;; net: widget 2900@20%=580, tea 5800@5%=290 -> net tax 870 (gross was 900).
(commerce-test
"net-quote"
(cart-quote-net gctx cart ruleset (list))
{:codes (list "TEN") :subtotal 9000 :discount 300 :total 9570 :tax 870})
;; same cart through the gross policy taxes 900 (the documented default)
(commerce-test
"gross-quote-for-contrast"
(quote-tax (cart-quote gctx cart ruleset (list)))
900)
(commerce-test
"net-tax-lower"
(quote-tax (cart-quote-net gctx cart ruleset (list)))
870)
;; --- no discount: net policy == gross policy ---
(commerce-test
"no-discount-net-equals-gross"
(=
(cart-quote-net gctx cart (list) (list))
(cart-quote gctx cart (list) (list)))
true)
;; --- empty cart ---
(commerce-test
"net-empty"
(cart-quote-net gctx empty-cart ruleset (list))
{:codes (list) :subtotal 0 :discount 0 :total 0 :tax 0})

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;; lib/commerce/tests/order.sx — order lifecycle as a flow-on-sx flow.
;; Uses (commerce-test name got expected) provided by conformance.sh.
;; Builds the (expensive) flow env once; all assertions share it.
(define env (order-make-env))
(define b (persist/mem-backend))
(define q1 {:codes (list) :subtotal 1000 :discount 0 :total 1200 :tax 200})
;; --- happy path: begin suspends at payment ---
(define id1 (order-begin! env b "O1" 100 q1))
(commerce-test "begin-status-reserved" (order-status b "O1") :reserved)
(commerce-test "begin-waiting-payment" (order-flow-waiting env id1) "payment")
(commerce-test "begin-not-yet-paid" (order-paid b "O1") 0)
;; --- settle: payment webhook drives fulfilment ---
(define s1 (order-settle! env b id1 "O1" "ref-1" 102 1200))
(commerce-test "settle-result" s1 :settled)
(commerce-test "settle-status-fulfilled" (order-status b "O1") :fulfilled)
(commerce-test "settle-flow-done" (order-flow-status env id1) "done")
(commerce-test "settle-recon-ok" (order-recon b "O1") :ok)
(commerce-test "settle-event-count" (len (order-events b "O1")) 4)
;; --- webhook replay: a second settle is a no-op ---
(define s1b (order-settle! env b id1 "O1" "ref-1" 102 1200))
(commerce-test "replay-already-settled" s1b :already-settled)
(commerce-test
"replay-no-extra-events"
(len (order-events b "O1"))
4)
(commerce-test "replay-recon-still-ok" (order-recon b "O1") :ok)
;; --- a second order gets its own flow id and suspends independently ---
(define id2 (order-begin! env b "O2" 200 q1))
(commerce-test "second-distinct-id" (not (= id1 id2)) true)
(commerce-test
"second-waiting-payment"
(order-flow-waiting env id2)
"payment")
(commerce-test "first-unaffected" (order-status b "O1") :fulfilled)
;; --- durability: a suspended order survives a process restart ---
(define id3 (order-begin! env b "O3" 300 q1))
(commerce-test "pre-restart-waiting" (order-flow-waiting env id3) "payment")
(define _restart (order-flow-restart! env))
(commerce-test
"post-restart-still-waiting"
(order-flow-waiting env id3)
"payment")
(commerce-test "post-restart-ledger-intact" (order-status b "O3") :reserved)
(define s3 (order-settle! env b id3 "O3" "ref-3" 302 1200))
(commerce-test "post-restart-settled" s3 :settled)
(commerce-test "post-restart-status" (order-status b "O3") :fulfilled)
(commerce-test "post-restart-recon-ok" (order-recon b "O3") :ok)
(commerce-test "post-restart-flow-done" (order-flow-status env id3) "done")
;; --- payment-request envelope (provider-neutral) for the still-suspended O2 ---
(commerce-test
"pending-payments-lists-suspended"
(pending-payments env b :GBP "https://shop/return")
(list {:id id2 :request {:order "O2" :amount 1200 :return-url "https://shop/return" :currency :GBP}}))

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;; lib/commerce/tests/payment.sx — provider-neutral payment-request envelope.
;; Uses (commerce-test name got expected) provided by conformance.sh.
;; Envelope construction is ledger-only (no flow env); pending-payments (which
;; needs the flow env) is exercised in the order suite.
(define q1 {:codes (list) :subtotal 1000 :discount 0 :total 1200 :tax 200})
(define q2 {:codes (list) :subtotal 5000 :discount 500 :total 4500 :tax 0})
(define b (persist/mem-backend))
(define _c1 (order-create b "P1" 1 q1))
(define _c2 (order-create b "P2" 1 q2))
(commerce-test
"envelope"
(payment-request b "P1" :GBP "https://shop/return")
{:order "P1" :amount 1200 :return-url "https://shop/return" :currency :GBP})
(commerce-test
"envelope-amount"
(payment-request-amount (payment-request b "P1" :GBP "x"))
1200)
(commerce-test
"envelope-currency"
(payment-request-currency (payment-request b "P1" :GBP "x"))
:GBP)
(commerce-test
"envelope-order"
(payment-request-order (payment-request b "P1" :GBP "x"))
"P1")
(commerce-test
"envelope-return-url"
(payment-request-return-url (payment-request b "P1" :GBP "https://r"))
"https://r")
;; amount tracks the ledger total, currency is per-call (provider/instance config)
(commerce-test
"envelope-amount-2"
(payment-request-amount (payment-request b "P2" :EUR "x"))
4500)
(commerce-test
"envelope-currency-2"
(payment-request-currency (payment-request b "P2" :EUR "x"))
:EUR)

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;; lib/commerce/tests/price.sx — subtotal + jurisdiction-relational tax.
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define
pcat
(make-catalog
(list
(list "widget" 1000 :standard)
(list "book" 800 :zero-rated)
(list "tea" 1000 :reduced))
(list
(list "widget" :small -200)
(list "widget" :large 500))
(list)))
(define
rules
(list
(list :uk :standard :guest 2000)
(list :uk :reduced :guest 500)
(list :uk :zero-rated :guest 0)
(list :uk :standard :member 1000)
(list :ie :standard :guest 2300)))
(define gctx (make-pricing-context pcat rules :uk :guest))
(define mctx (make-pricing-context pcat rules :uk :member))
;; --- unit + line pricing ---
(commerce-test
"unit-price-variant"
(line-unit-price pcat "widget" :small)
800)
(commerce-test
"unit-price-no-variant"
(line-unit-price pcat "widget" :none)
1000)
(commerce-test "unit-price-unknown" (line-unit-price pcat "ghost" :none) nil)
(commerce-test
"line-extended"
(line-extended pcat (list "widget" :small 2))
1600)
;; --- subtotal ---
(define
cart1
(list (list "widget" :small 2) (list "book" :none 1)))
(commerce-test "subtotal" (cart-subtotal pcat cart1) 2400)
(commerce-test "subtotal-empty" (cart-subtotal pcat empty-cart) 0)
;; --- tax rate lookup (relational, both directions) ---
(commerce-test
"rate-forward"
(rate-bps rules :uk :standard :guest)
2000)
(commerce-test
"rate-missing"
(rate-bps rules :fr :standard :guest)
0)
(commerce-test
"rate-juris-by-bps-backward"
(run* j (fresh (cust) (taxo rules j :standard cust 2300)))
(list :ie))
(commerce-test
"rate-customer-by-bps-backward"
(run* cust (taxo rules :uk :standard cust 1000))
(list :member))
;; --- apply-bps rounding (half up, integer only) ---
(commerce-test "bps-exact" (apply-bps 1600 2000) 320)
(commerce-test "bps-round-up" (apply-bps 799 2000) 160)
(commerce-test "bps-zero" (apply-bps 800 0) 0)
;; --- line + cart tax ---
(commerce-test
"line-tax-standard"
(line-tax gctx (list "widget" :small 2))
320)
(commerce-test
"line-tax-zero-rated"
(line-tax gctx (list "book" :none 1))
0)
(commerce-test
"line-tax-member"
(line-tax mctx (list "widget" :small 2))
160)
(commerce-test "cart-tax-guest" (cart-tax gctx cart1) 320)
;; --- total dict (deterministic) ---
(commerce-test "total-guest" (cart-total gctx cart1) {:subtotal 2400 :discounts 0 :total 2720 :tax 320})
(commerce-test "total-member" (cart-total mctx cart1) {:subtotal 2400 :discounts 0 :total 2560 :tax 160})
(commerce-test "total-empty" (cart-total gctx empty-cart) {:subtotal 0 :discounts 0 :total 0 :tax 0})

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;; lib/commerce/tests/promo.sx — promo rules + relational enumeration.
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define
pcat
(make-catalog
(list
(list "widget" 1000 :standard)
(list "book" 800 :zero-rated)
(list "tea" 1000 :reduced))
(list)
(list)))
(define gctx (make-pricing-context pcat (list) :uk :guest))
(define mctx (make-pricing-context pcat (list) :uk :member))
(define
cart
(list
(list "widget" :none 3)
(list "book" :none 1)
(list "tea" :none 6)))
(define
ruleset
(list
(list :percent "TEN" :standard 1000)
(list :fixed "FIVER" 5000 500)
(list :bundle "B3T" "tea" 3)
(list :member "MEM" :standard 1500)))
;; --- per-type amounts ---
(commerce-test
"percent-amount"
(promo-amount gctx cart (list :percent "TEN" :standard 1000))
300)
(commerce-test
"fixed-amount-met"
(promo-amount gctx cart (list :fixed "FIVER" 5000 500))
500)
(commerce-test
"fixed-amount-not-met"
(promo-amount
gctx
(list (list "widget" :none 1))
(list :fixed "FIVER" 5000 500))
0)
(commerce-test
"fixed-amount-capped"
(promo-amount
gctx
(list (list "book" :none 1))
(list :fixed "BIG" 0 9999))
800)
(commerce-test
"bundle-amount"
(promo-amount gctx cart (list :bundle "B3T" "tea" 3))
2000)
(commerce-test
"member-amount-guest"
(promo-amount gctx cart (list :member "MEM" :standard 1500))
0)
(commerce-test
"member-amount-member"
(promo-amount mctx cart (list :member "MEM" :standard 1500))
450)
;; --- relational enumeration: forward ---
(commerce-test
"discounto-all-guest"
(run*
pair
(fresh
(code amount)
(promo-discounto gctx cart ruleset code amount)
(== pair (list code amount))))
(list
(list "TEN" 300)
(list "FIVER" 500)
(list "B3T" 2000)
(list "MEM" 0)))
(commerce-test
"applicable-guest"
(applicable-promos gctx cart ruleset)
(list
(list "TEN" 300)
(list "FIVER" 500)
(list "B3T" 2000)))
(commerce-test
"applicable-member"
(applicable-promos mctx cart ruleset)
(list
(list "TEN" 300)
(list "FIVER" 500)
(list "B3T" 2000)
(list "MEM" 450)))
;; --- relational enumeration: backward (the showcase) ---
(commerce-test
"code-by-discount-2000"
(run* code (promo-applieso gctx cart ruleset code 2000))
(list "B3T"))
(commerce-test
"code-by-discount-500"
(run* code (promo-applieso gctx cart ruleset code 500))
(list "FIVER"))
(commerce-test
"code-by-discount-none"
(run* code (promo-applieso gctx cart ruleset code 9999))
(list))
;; --- deterministic helpers ---
(commerce-test
"amount-for-ten"
(promo-amount-for gctx cart ruleset "TEN")
300)
(commerce-test
"amount-for-mem-guest"
(promo-amount-for gctx cart ruleset "MEM")
0)
(commerce-test
"amount-for-mem-member"
(promo-amount-for mctx cart ruleset "MEM")
450)
(commerce-test
"amount-for-absent"
(promo-amount-for gctx cart ruleset "NOPE")
0)

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;; lib/commerce/tests/quote.sx — composed priced quote (price+promo+stacking).
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define
pcat
(make-catalog
(list
(list "widget" 1000 :standard)
(list "book" 800 :zero-rated)
(list "tea" 1000 :reduced))
(list)
(list)))
(define
tax-rules
(list
(list :uk :standard :guest 2000)
(list :uk :reduced :guest 500)
(list :uk :zero-rated :guest 0)
(list :uk :standard :member 2000)
(list :uk :reduced :member 500)
(list :uk :zero-rated :member 0)))
(define gctx (make-pricing-context pcat tax-rules :uk :guest))
(define mctx (make-pricing-context pcat tax-rules :uk :member))
(define
cart
(list
(list "widget" :none 3)
(list "book" :none 1)
(list "tea" :none 6)))
(define
ruleset
(list
(list :percent "TEN" :standard 1000)
(list :percent "TWENTY" :standard 2000)
(list :fixed "FIVER" 5000 500)
(list :bundle "B3T" "tea" 3)
(list :member "MEM" :standard 2500)))
(define
exclusions
(list (list "TEN" "TWENTY") (list "TEN" "MEM") (list "TWENTY" "MEM")))
;; subtotal: 3000 + 800 + 6000 = 9800
;; tax (gross): widget 600 + tea 300 + book 0 = 900
;; guest discount: TWENTY 600 + FIVER 500 + B3T 2000 = 3100
;; guest total: 9800 - 3100 + 900 = 7600
(define gq (cart-quote gctx cart ruleset exclusions))
(commerce-test "quote-subtotal" (quote-subtotal gq) 9800)
(commerce-test "quote-tax" (quote-tax gq) 900)
(commerce-test "quote-discount-guest" (quote-discount gq) 3100)
(commerce-test "quote-total-guest" (quote-total gq) 7600)
(commerce-test
"quote-codes-guest"
(quote-codes gq)
(list "TWENTY" "FIVER" "B3T"))
(commerce-test "quote-full-guest" gq {:codes (list "TWENTY" "FIVER" "B3T") :subtotal 9800 :discount 3100 :total 7600 :tax 900})
;; member discount: MEM 750 + FIVER 500 + B3T 2000 = 3250
;; member total: 9800 - 3250 + 900 = 7450
(define mq (cart-quote mctx cart ruleset exclusions))
(commerce-test "quote-discount-member" (quote-discount mq) 3250)
(commerce-test "quote-total-member" (quote-total mq) 7450)
(commerce-test
"quote-codes-member"
(quote-codes mq)
(list "FIVER" "B3T" "MEM"))
;; --- determinism: same inputs, identical quote ---
(commerce-test
"quote-deterministic"
(=
(cart-quote gctx cart ruleset exclusions)
(cart-quote gctx cart ruleset exclusions))
true)
;; --- no promos: discount 0, total = subtotal + tax ---
(commerce-test
"quote-no-promos"
(cart-quote gctx cart (list) (list))
{:codes (list) :subtotal 9800 :discount 0 :total 10700 :tax 900})
;; --- empty cart ---
(commerce-test
"quote-empty"
(cart-quote gctx empty-cart ruleset exclusions)
{:codes (list) :subtotal 0 :discount 0 :total 0 :tax 0})
;; --- session convenience ---
(define
sess
(commerce-add (commerce-session gctx) "widget" :none 3))
(commerce-test
"session-quote"
(quote-total (session-quote sess ruleset exclusions))
3000)

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;; lib/commerce/tests/recon.sx — reconciliation as relational ledger queries.
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define q1 {:codes (list) :subtotal 1000 :discount 0 :total 1200 :tax 200})
(define b (persist/mem-backend))
;; OK1 — clean payment
(define _ok (order-create b "OK1" 1 q1))
(define _okp (order-pay b "OK1" "ok-ref" 2 1200))
;; OVER1 — double charge under two different refs
(define _ov (order-create b "OVER1" 1 q1))
(define _ova (order-pay b "OVER1" "ov-a" 2 1200))
(define _ovb (order-pay b "OVER1" "ov-b" 3 1200))
;; UNDER1 — short payment
(define _un (order-create b "UNDER1" 1 q1))
(define _unp (order-pay b "UNDER1" "un-ref" 2 900))
;; PART1 — paid in full, then partially refunded
(define _pa (order-create b "PART1" 1 q1))
(define _pap (order-pay b "PART1" "pa-ref" 2 1200))
(define _par (order-refund b "PART1" "pa-rf" 3 200))
;; REPLAY1 — webhook fires twice with the same ref (idempotent)
(define _rp (order-create b "REPLAY1" 1 q1))
(define _rpa (order-pay b "REPLAY1" "rp-ref" 2 1200))
(define _rpb (order-pay b "REPLAY1" "rp-ref" 2 1200))
;; PEND1 — created, not yet paid
(define _pe (order-create b "PEND1" 1 q1))
;; --- summaries ---
(commerce-test "summary-count" (len (ledger-summaries b)) 6)
(commerce-test
"summary-ok1"
(order-summary b "order/OK1")
(list "order/OK1" 1200 1200 0 1200 :ok))
(commerce-test
"summary-part1"
(order-summary b "order/PART1")
(list "order/PART1" 1200 1200 200 1000 :underpaid))
;; --- forward status query ---
(commerce-test
"status-forward-ok"
(run* st (recon-statuso (ledger-summaries b) "order/OK1" st))
(list :ok))
;; --- backward status queries (the showcase) ---
(commerce-test
"settled"
(sort (settled-orders b))
(sort (list "order/OK1" "order/REPLAY1")))
(commerce-test "overpaid" (overpaid-orders b) (list "order/OVER1"))
(commerce-test
"underpaid"
(sort (underpaid-orders b))
(sort (list "order/UNDER1" "order/PART1")))
(commerce-test "unpaid" (unpaid-orders b) (list "order/PEND1"))
(commerce-test
"mismatched"
(sort (mismatched-orders b))
(sort (list "order/OVER1" "order/UNDER1" "order/PART1")))
;; --- backward net-amount query ---
(commerce-test
"net-1200"
(sort (orders-with-net b 1200))
(sort (list "order/OK1" "order/REPLAY1")))
(commerce-test
"net-2400"
(orders-with-net b 2400)
(list "order/OVER1"))
(commerce-test
"net-900"
(orders-with-net b 900)
(list "order/UNDER1"))
;; --- discrepancy: +1200 (over) - 300 (under) - 200 (refund) = 700 ---
(commerce-test "discrepancy" (ledger-discrepancy b) 700)
;; --- double-charge guard ---
(commerce-test "double-charge-detected" (order-recon b "OVER1") :overpaid)
(commerce-test "double-charge-amount" (order-paid b "OVER1") 2400)
;; --- partial refund ---
(commerce-test "partial-refund-net" (order-recon b "PART1") :underpaid)
(commerce-test
"partial-refund-amount"
(order-refunded-amount-of (order-events b "PART1"))
200)
;; --- webhook replay: same ref twice records once ---
(commerce-test
"replay-single-event"
(len (order-events b "REPLAY1"))
2)
(commerce-test "replay-paid-once" (order-paid b "REPLAY1") 1200)
(commerce-test "replay-settled" (order-recon b "REPLAY1") :ok)

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;; lib/commerce/tests/refund.sx — refund lifecycle as a flow-on-sx flow.
;; Uses (commerce-test name got expected) provided by conformance.sh.
;; Builds the (expensive) flow env once; all assertions share it.
(define env (refund-make-env))
(define b (persist/mem-backend))
(define q1 {:codes (list) :subtotal 1000 :discount 0 :total 1200 :tax 200})
;; a paid, fulfilled order to refund (set up directly via the ledger)
(define _c (order-create b "O1" 1 q1))
(define _p (order-pay b "O1" "pay-1" 2 1200))
(commerce-test "setup-recon-ok" (order-recon b "O1") :ok)
;; --- happy path: request -> approve -> settle ---
(define rid (refund-begin! env b "O1" "rf-1" 10 500))
(commerce-test "begin-waiting-approve" (order-flow-waiting env rid) "approve")
(commerce-test
"begin-not-yet-refunded"
(order-refunded-amount-of (order-events b "O1"))
0)
(commerce-test "begin-recon-unchanged" (order-recon b "O1") :ok)
(define a1 (refund-approve! env rid))
(commerce-test "approve-result" a1 :approved)
(commerce-test "approve-waiting-settle" (order-flow-waiting env rid) "settle")
(define s1 (refund-settle! env b rid "O1" "rf-1" 11 500))
(commerce-test "settle-result" s1 :settled)
(commerce-test "settle-flow-done" (order-flow-status env rid) "done")
(commerce-test
"settle-refunded-amount"
(order-refunded-amount-of (order-events b "O1"))
500)
;; net 1200 - 500 = 700 < total 1200 -> underpaid (partial refund)
(commerce-test "settle-recon-underpaid" (order-recon b "O1") :underpaid)
;; --- idempotent settle: replayed provider callback is a no-op ---
(define s1b (refund-settle! env b rid "O1" "rf-1" 11 500))
(commerce-test "replay-already-settled" s1b :already-settled)
(commerce-test
"replay-refunded-once"
(order-refunded-amount-of (order-events b "O1"))
500)
;; --- reject path: approval denied, books untouched ---
(define _c2 (order-create b "O2" 1 q1))
(define _p2 (order-pay b "O2" "pay-2" 2 1200))
(define rid2 (refund-begin! env b "O2" "rf-2" 20 1200))
(commerce-test
"reject-waiting-approve"
(order-flow-waiting env rid2)
"approve")
(define j2 (refund-reject! env b "O2" rid2 21 "policy"))
(commerce-test "reject-result" j2 :rejected)
(commerce-test "reject-flow-not-waiting" (order-flow-waiting env rid2) nil)
(commerce-test
"reject-no-refund"
(order-refunded-amount-of (order-events b "O2"))
0)
(commerce-test "reject-recon-ok" (order-recon b "O2") :ok)
;; settling a rejected/cancelled refund does nothing
(define s2 (refund-settle! env b rid2 "O2" "rf-2" 22 1200))
(commerce-test "reject-then-settle-noop" s2 :already-settled)
(commerce-test
"reject-still-no-refund"
(order-refunded-amount-of (order-events b "O2"))
0)
;; --- distinct flow ids ---
(commerce-test "distinct-refund-ids" (not (= rid rid2)) true)

127
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@@ -0,0 +1,127 @@
;; lib/commerce/tests/stack.sx — stacking precedence, exclusivity, best price.
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define
pcat
(make-catalog
(list
(list "widget" 1000 :standard)
(list "book" 800 :zero-rated)
(list "tea" 1000 :reduced))
(list)
(list)))
(define gctx (make-pricing-context pcat (list) :uk :guest))
(define mctx (make-pricing-context pcat (list) :uk :member))
(define
cart
(list
(list "widget" :none 3)
(list "book" :none 1)
(list "tea" :none 6)))
(define
ruleset
(list
(list :percent "TEN" :standard 1000)
(list :percent "TWENTY" :standard 2000)
(list :fixed "FIVER" 5000 500)
(list :bundle "B3T" "tea" 3)
(list :member "MEM" :standard 2500)))
;; The three standard-class discounts are mutually exclusive.
(define
exclusions
(list (list "TEN" "TWENTY") (list "TEN" "MEM") (list "TWENTY" "MEM")))
;; --- exclusivity predicates ---
(commerce-test
"excluded-pair-direct"
(excluded-pair? exclusions "TEN" "TWENTY")
true)
(commerce-test
"excluded-pair-symmetric"
(excluded-pair? exclusions "TWENTY" "TEN")
true)
(commerce-test
"excluded-pair-none"
(excluded-pair? exclusions "TEN" "FIVER")
false)
(commerce-test
"compatible-yes"
(compatible? exclusions (list "FIVER" "B3T" "TWENTY"))
true)
(commerce-test
"compatible-no"
(compatible? exclusions (list "TEN" "TWENTY" "B3T"))
false)
;; --- powerset + valid stackings ---
(commerce-test
"powerset-size"
(len (powerset (list 1 2 3 4)))
16)
(define gappl (applicable-promos gctx cart ruleset))
(commerce-test "applicable-guest-count" (len gappl) 4)
;; 16 subsets minus the 4 containing both TEN and TWENTY = 12 legal.
(commerce-test
"valid-stackings-count"
(len (valid-stackings exclusions gappl))
12)
(commerce-test
"stacking-total"
(stacking-total (list (list "TWENTY" 600) (list "B3T" 2000)))
2600)
;; --- best price (deterministic selection) ---
(commerce-test
"best-discount-guest"
(best-promo-discount gctx cart ruleset exclusions)
3100)
(commerce-test
"best-codes-guest"
(best-promo-codes gctx cart ruleset exclusions)
(list "TWENTY" "FIVER" "B3T"))
;; exclusivity holds: the cheaper conflicting code is dropped.
(commerce-test
"best-excludes-ten"
(some
(fn (c) (= c "TEN"))
(best-promo-codes gctx cart ruleset exclusions))
false)
;; --- member vs guest ---
(commerce-test
"best-discount-member"
(best-promo-discount mctx cart ruleset exclusions)
3250)
(commerce-test
"best-codes-member"
(best-promo-codes mctx cart ruleset exclusions)
(list "FIVER" "B3T" "MEM"))
;; --- best price backward query (the showcase) ---
(commerce-test
"stacking-by-total-backward"
(run*
codes
(stacking-by-totalo (valid-stackings exclusions gappl) codes 3100))
(list (list "TWENTY" "FIVER" "B3T")))
;; --- edge: no applicable promos ---
(commerce-test
"best-empty"
(best-promo-discount gctx empty-cart ruleset exclusions)
0)

122
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@@ -0,0 +1,122 @@
;; lib/commerce/tests/stock.sx — stock-constrained reservation.
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define
cat
(make-catalog
(list
(list "widget" 1000 :standard)
(list "gadget" 2500 :standard))
(list)
(list
(list "widget" :small 5)
(list "widget" :large 0)
(list "gadget" :std 12))))
;; --- availability ---
(commerce-test
"available-found"
(available-stock cat "widget" :small)
5)
(commerce-test
"available-zero"
(available-stock cat "widget" :large)
0)
(commerce-test
"available-absent"
(available-stock cat "widget" :none)
0)
;; --- per-line reservability ---
(commerce-test
"shortfall-fits"
(line-shortfall cat (list "widget" :small 5))
0)
(commerce-test
"shortfall-over"
(line-shortfall cat (list "widget" :small 8))
3)
(commerce-test
"reservable-yes"
(line-reservable? cat (list "gadget" :std 12))
true)
(commerce-test
"reservable-no"
(line-reservable? cat (list "widget" :large 1))
false)
;; --- cart-level reservation check ---
(commerce-test
"can-reserve-yes"
(can-reserve?
cat
(list (list "widget" :small 5) (list "gadget" :std 2)))
true)
(commerce-test
"can-reserve-no"
(can-reserve? cat (list (list "widget" :small 9)))
false)
(commerce-test
"shortfalls-detail"
(reservation-shortfalls
cat
(list (list "widget" :small 9) (list "gadget" :std 2)))
(list {:requested 9 :available 5 :sku "widget" :variant :small :short 4}))
(commerce-test
"reserve-check-ok"
(reserve-check cat (list (list "gadget" :std 1)))
:ok)
(commerce-test
"reserve-check-rejected"
(reserve-check cat (list (list "widget" :large 1)))
{:shortfalls (list {:requested 1 :available 0 :sku "widget" :variant :large :short 1}) :rejected :insufficient-stock})
;; --- reservation view: concurrent holds reduce availability ---
(define held (list (list "widget" :small 3)))
(commerce-test
"effective-after-hold"
(effective-available cat held "widget" :small)
2)
(commerce-test
"effective-other-unaffected"
(effective-available cat held "gadget" :std)
12)
(commerce-test
"reservable-with-fits"
(line-reservable-with? cat held (list "widget" :small 2))
true)
(commerce-test
"reservable-with-over"
(line-reservable-with? cat held (list "widget" :small 3))
false)
;; --- relational availability query (multidirectional) ---
(commerce-test
"sufficient-forward"
(run*
x
(fresh () (sufficient-stocko cat "widget" :small 5) (== x true)))
(list true))
(commerce-test
"sufficient-forward-over"
(run*
x
(fresh () (sufficient-stocko cat "widget" :small 6) (== x true)))
(list))
;; backward: which variants of widget can supply 1 unit?
(commerce-test
"variants-supplying-1"
(run* v (fresh (q) (stocko cat "widget" v q) (lteo-i 1 q)))
(list :small))

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@@ -0,0 +1,112 @@
;; lib/commerce/tests/window.sx — time-windowed promotions.
;; Uses (commerce-test name got expected) provided by conformance.sh.
(define
pcat
(make-catalog (list (list "widget" 1000 :standard)) (list) (list)))
(define gctx (make-pricing-context pcat (list) :uk :guest))
(define cart (list (list "widget" :none 3)))
(define ten (list :percent "TEN" :standard 1000))
(define twenty (list :percent "TWENTY" :standard 2000))
(define always (list :fixed "ALWAYS" 0 100))
(define
windowed
(list
(windowed-promo ten 100 200)
(windowed-promo twenty 150 300)
(windowed-promo always nil nil)))
(define exclusions (list (list "TEN" "TWENTY")))
;; --- wp-active? boundaries (inclusive) ---
(commerce-test
"active-at-from"
(wp-active? (windowed-promo ten 100 200) 100)
true)
(commerce-test
"active-at-until"
(wp-active? (windowed-promo ten 100 200) 200)
true)
(commerce-test
"inactive-before"
(wp-active? (windowed-promo ten 100 200) 99)
false)
(commerce-test
"inactive-after"
(wp-active? (windowed-promo ten 100 200) 201)
false)
(commerce-test
"open-ended-always"
(wp-active? (windowed-promo always nil nil) 99999)
true)
(commerce-test
"open-lower"
(wp-active? (windowed-promo ten nil 200) 1)
true)
(commerce-test
"open-upper"
(wp-active? (windowed-promo ten 100 nil) 99999)
true)
;; --- active-ruleset filtering ---
(commerce-test
"active-ruleset-120"
(active-ruleset windowed 120)
(list ten always))
(commerce-test
"active-ruleset-160"
(active-ruleset windowed 160)
(list ten twenty always))
(commerce-test
"active-ruleset-250"
(active-ruleset windowed 250)
(list twenty always))
(commerce-test
"active-ruleset-50"
(active-ruleset windowed 50)
(list always))
;; --- active-codes (backward query) ---
(commerce-test
"active-codes-120"
(active-codes windowed 120)
(list "TEN" "ALWAYS"))
(commerce-test
"active-codes-160"
(active-codes windowed 160)
(list "TEN" "TWENTY" "ALWAYS"))
(commerce-test
"active-codes-50"
(active-codes windowed 50)
(list "ALWAYS"))
;; --- windowed-quote: discount changes with time (deterministic) ---
;; subtotal 3000, no tax. TEN=300, TWENTY=600, ALWAYS=100; TEN/TWENTY exclusive.
(commerce-test
"quote-50"
(quote-discount (windowed-quote gctx cart windowed exclusions 50))
100)
(commerce-test
"quote-120"
(quote-discount (windowed-quote gctx cart windowed exclusions 120))
400)
(commerce-test
"quote-160"
(quote-discount (windowed-quote gctx cart windowed exclusions 160))
700)
(commerce-test
"quote-250"
(quote-discount (windowed-quote gctx cart windowed exclusions 250))
700)
(commerce-test
"quote-total-160"
(quote-total (windowed-quote gctx cart windowed exclusions 160))
2300)

55
lib/commerce/window.sx Normal file
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@@ -0,0 +1,55 @@
;; lib/commerce/window.sx — time-windowed promotions.
;;
;; A promo's validity window is kept SEPARATE from the promo tuple (so promo.sx
;; is untouched): a windowed promo is (list promo from until) with inclusive
;; integer timestamps (same time model as the ledger `at`). nil from = no lower
;; bound; nil until = open-ended.
;;
;; `active-ruleset` filters a windowed ruleset to the plain promos live at a
;; given time, which feeds straight into promo/stack/quote — so a datetime-aware
;; quote is just the existing pipeline over the active set. Deterministic: the
;; quote is a pure function of (ctx, cart, windowed-ruleset, exclusions, at).
(define windowed-promo (fn (promo from until) (list promo from until)))
(define wp-promo (fn (wp) (nth wp 0)))
(define wp-from (fn (wp) (nth wp 1)))
(define wp-until (fn (wp) (nth wp 2)))
(define
wp-active?
(fn
(wp at)
(let
((from (wp-from wp)) (until (wp-until wp)))
(and (or (nil? from) (>= at from)) (or (nil? until) (<= at until))))))
;; Plain promo tuples live at time `at` — feed into cart-quote / best-promo-*.
(define
active-ruleset
(fn
(windowed at)
(map wp-promo (filter (fn (wp) (wp-active? wp at)) windowed))))
;; Relation: which promo codes are active at `at`? (backward query)
(define
active-promoo
(fn
(windowed at code)
(fresh
(wp)
(membero wp windowed)
(project
(wp)
(if (wp-active? wp at) (== code (promo-code (wp-promo wp))) fail)))))
(define
active-codes
(fn (windowed at) (run* code (active-promoo windowed at code))))
;; Datetime-aware quote: the existing pipeline over the time-active ruleset.
(define
windowed-quote
(fn
(ctx cart windowed exclusions at)
(cart-quote ctx cart (active-ruleset windowed at) exclusions)))

View File

@@ -21,7 +21,7 @@ reconciliation — all auditable via the event log.
## Status (rolling)
`bash lib/commerce/conformance.sh`**0/0** (not yet started)
`bash lib/commerce/conformance.sh`**297/297** (18 suites; + integration) — **roadmap + Phase 5 backlog + e2e composition proof complete**
## Ground rules
@@ -55,28 +55,223 @@ lib/commerce/api.sx ── (commerce/add) (commerce/total) (commerce/checkout)
```
## Phase 1 — Catalog + cart + deterministic totals
- [ ] `catalog.sx` — product/variant/stock as facts
- [ ] `cart.sx` — line items, add/remove/qty
- [ ] `price.sx` — base pricing relation, subtotal; tax
- [ ] `api.sx` + tests + scoreboard + conformance.sh
- [x] `catalog.sx` — product/variant/stock as facts
- [x] `cart.sx` — line items, add/remove/qty
- [x] `price.sx` — base pricing relation, subtotal; tax
- [x] `api.sx` + tests + scoreboard + conformance.sh
## Phase 2 — Promotions (relational)
- [ ] promo rules: percentage, fixed, bundle, member rate
- [ ] explicit stacking precedence; "best price" backward query
- [ ] tests: stacking order, mutually-exclusive promos, member vs guest
- [x] promo rules: percentage, fixed, bundle, member rate
- [x] explicit stacking precedence; "best price" backward query
- [x] tests: stacking order, mutually-exclusive promos, member vs guest
## Phase 3 — Order lifecycle (flow + store)
- [ ] order flow: reserve stock → await payment → fulfil
- [ ] payment webhook resumes the suspended flow
- [ ] order ledger as a `persist` stream; idempotent reconciliation
- [x] order flow: reserve stock → await payment → fulfil
- [x] payment webhook resumes the suspended flow
- [x] order ledger as a `persist` stream; idempotent reconciliation
## Phase 4 — Reconciliation + federation
- [ ] mismatch detection (paid≠ordered) as queries over the ledger
- [ ] cross-instance catalog (federated marketplace) — out-of-scope stub
- [ ] tests: webhook replay, partial refund, double-charge guard
- [x] mismatch detection (paid≠ordered) as queries over the ledger
- [x] cross-instance catalog (federated marketplace) — out-of-scope stub
- [x] tests: webhook replay, partial refund, double-charge guard
## Phase 5 — Extensions (backlog; base roadmap complete) — **ALL DONE (278/278)**
Thesis-aligned deepenings of the relational/composition showcase. Pick the one
that unlocks the most tests per effort each iteration.
- [x] line-level discount attribution — "which line item triggered this discount?"
as a backward miniKanren query (`attribution.sx`: `promo-toucheso` relation,
`lines-for-code`/`codes-for-line` both directions, `order-level-codes` for fixed).
- [x] time-windowed promotions — `window.sx`: windowed promo `(promo from until)`,
`active-ruleset`/`active-codes`/`windowed-quote` gate by datetime; feeds the
existing promo/stack/quote pipeline unchanged. Determinism preserved.
- [x] discount-aware tax policy — `nettax.sx`: `cart-quote-net` taxes the net
(post-discount) base; `allocate-discount` spreads the basket discount across
lines by extended share with largest-remainder so per-line shares sum exactly.
- [x] refund as a flow — `refund.sx`: refund lifecycle (request → approve →
settle) as a second flow-on-sx flow with two suspension points; idempotent
settle, reject path, ledger-recorded; reuses order.sx flow helpers.
- [x] stock-constrained reservation — `stock.sx`: `can-reserve?`/`reserve-check`
precondition (host gates order-begin! on it, keeping the flow pure);
`reservation-shortfalls` detail; `effective-available` nets out concurrent
reservations; `sufficient-stocko` relational availability query.
- [x] provider-neutral payment-request envelope — `payment.sx`: `payment-request`
materialises `{:order :amount :currency :return-url}` at the IO edge (amount from
the ledger, currency/return-url host-supplied); `pending-payments` enumerates
suspended orders with their envelopes (host poller seam). Engine stays vendor-
agnostic; `order-settle!(ref, amount)` is the resume seam.
## Progress log
(loop fills this in)
- 2026-06-07 — `tests/integration.sx` (hardening): end-to-end composition proof —
one narrative across every module (catalog → stock check → quote[promo+stack+tax]
→ attribution → order flow → payment envelope → settle → recon → refund flow →
ledger mismatch) asserting the seams tie together with consistent numbers
(subtotal 2400, discount 210, tax 320, total 2510; settle→:ok; refund 510→
:underpaid; mismatch flagged). Proves the three-substrate composition. One env
with both order+refund flows. integration suite 19/19; total 297/297 (18 suites).
- 2026-06-07 — `refund.sx` (**Phase 5 backlog complete**): refund lifecycle as a
second flow-on-sx flow `(lambda (oid) (begin (request 'approve oid) (request
'settle oid)))` — two suspension points (approval = human/policy decision,
settle = provider). `refund-begin!` records :refund-requested and suspends at
approval; `refund-approve!` advances to settle; `refund-settle!` records
:refunded (idempotent) and completes; `refund-reject!` records :refund-rejected
and cancels the flow. Only :refunded moves the books, so requested/rejected
refunds leave recon unchanged. Reuses order.sx flow helpers. refund suite
20/20; total 278/278 (17 suites). NB: conformance now has two env-building
suites (order, refund) — each builds the ~150s flow env in its own process.
- 2026-06-07 — `stock.sx` (Phase 5 ext): stock-constrained reservation. Design
choice: reservation is a precondition the host checks BEFORE order-begin!
(validate → begin), keeping the order flow pure orchestration. `available-stock`
reads the catalog stock facts; `can-reserve?`/`reserve-check`/
`reservation-shortfalls` gate a cart; `effective-available`/`line-reservable-with?`
net out concurrent reservations (no over-reserve); `sufficient-stocko` is the
multidirectional availability query. Only refund-as-flow remains in the
backlog. stock suite 19/19; total 258/258 (16 suites).
- 2026-06-07 — `nettax.sx` (Phase 5 ext): discount-aware tax — the alternative to
quote.sx's gross-tax default. `cart-quote-net` taxes the NET (post-discount)
base. `allocate-discount` spreads the basket-level discount across lines in
proportion to extended price with a deterministic largest-remainder pass so
per-line shares sum EXACTLY to the discount; each line is then taxed on its net
at its class rate. Both policies reproducible from inputs; pick per jurisdiction.
nettax suite 11/11; total 239/239 (15 suites).
- 2026-06-07 — `window.sx` (Phase 5 ext): time-windowed promotions. A validity
window is kept SEPARATE from the promo tuple — windowed promo `(promo from
until)` (inclusive int timestamps, nil = open bound). `active-ruleset` filters
to the plain promos live at `at` and feeds the existing promo/stack/quote
pipeline unchanged (promo.sx untouched); `active-promoo`/`active-codes` is the
backward "which codes are live at T?" query; `windowed-quote` is the
datetime-aware quote (deterministic in `at`). window suite 19/19; total 228/228.
- 2026-06-07 — `payment.sx` (Phase 5 ext, the item the user asked about):
provider-neutral payment-request envelope, materialised at the IO edge from the
ledger amount + host-supplied currency/return-url — keeps lib/commerce vendor-
agnostic (SumUp/Stripe adapters live in the orders service). `payment-request`
builds the `{:order :amount :currency :return-url}` envelope; `pending-payments`
is the host-poller seam listing suspended orders + their envelopes. Gotcha: a
Scheme **string** carried as a flow payload round-trips back to SX wrapped as
`{:scm-string "..."}` (numbers come back clean) — unwrap via `scm->string`
before using it as the oid. payment suite 7/7 + 1 order-suite integration test;
total 209/209 (13 suites).
- 2026-06-07 — `attribution.sx` (Phase 5 ext): line-level discount attribution —
the briefing's marquee "which line item triggered this discount?" query.
`promo-lines` is the pure per-promo scope (percent/member → class lines, bundle
→ sku lines, fixed → order-level/none); `promo-toucheso` relates (code, line)
for applying promos, run forward (`lines-for-code`) and backward
(`codes-for-line`). `order-level-codes` lists applying fixed promos; predicate
`line-touched-by?`. Additive — promo.sx amounts unchanged. attribution suite
16/16; total 201/201 (12 suites).
- 2026-06-07 — `recon.sx` + `federation.sx` (**Phase 4 complete — roadmap done**).
`recon.sx`: reconciliation as relational queries over the ledger. Per-order
summary tuples (id total paid refunded net status); `recon-statuso`/`neto`/
`mismatcho` are miniKanren relations, so "which orders are overpaid?",
"settled to net N?" are backward `run*` queries. Helpers: overpaid/underpaid/
settled/unpaid-orders, mismatched-orders, orders-with-net, ledger-discrepancy.
Tests cover double-charge guard (two refs → :overpaid), partial refund (net <
total → :underpaid), webhook replay (same ref twice → single :paid, :ok). 20/20.
`federation.sx` (out-of-scope stub): a federated catalog is the UNION of each
instance's product facts, so the SAME relations query cross-instance —
`fed-producto`/`fed-priceo`, `instances-with-sku`, `sku-offers`, deterministic
`cheapest-offer`. In-process mock, no real network/ActivityPub. 12/12.
Total 185/185 across 11 suites.
- 2026-06-07 — `order.sx` (**Phase 3 complete**, checkboxes 1-2): order lifecycle
as a flow-on-sx flow `(lambda (oid) (begin (request 'reserve oid) (request
'payment oid) (request 'fulfil oid)))` — pure orchestration carrying only the
order-id; the SX driver services each request by appending to the persist
ledger. `order-begin!` creates+reserves and leaves the flow SUSPENDED at
payment; `order-settle!` (the webhook) resumes → fulfils, and is idempotent
(only acts while waiting on payment, so a replayed webhook → :already-settled).
`order-flow-restart!` simulates a process restart entirely Scheme-side
(export→reset→reload→import) and the suspended order resumes correctly
afterwards with the persist ledger intact. Composes all three substrates
(minikanren pricing → flow lifecycle → persist ledger). order suite 21/21;
total 153/153. Gotchas: flow ids start at 1; never return flow-make-env across
the eval boundary (serializer hangs on the cyclic env); guest Scheme rejects
`:ok` keyword as a value — use `#t`. Flow env build ~150s CPU; order suite runs
single-process with timeout 560.
- 2026-06-07 — `ledger.sx` (Phase 3 piece, checkbox 3): order ledger as a
persist event stream "order/<id>". Status/total/paid/recon are projections
(folds) over events — ledger is the single source of truth. `order-pay`/
`order-refund` are idempotent via `persist/append-once` keyed on the payment
ref, so a replayed SumUp webhook records once (no double-charge). `order-recon-of`
classifies :unpaid/:ok/:underpaid/:overpaid on net (paidrefunded) vs total;
`ledger-mismatches` finds genuine paid≠ordered across all streams. Verified
minikanren+scheme/flow+persist all coexist in one sx_server process. ledger
suite 20/20; total 132/132. Next: order flow (reserve→pay→fulfil) as a Scheme
flow-on-sx flow with webhook resume (checkboxes 1-2) — needs SX↔Scheme quote
marshalling.
- 2026-06-07 — `quote.sx` (pricing capstone, bridges Phase 2→3): `cart-quote`
composes price+promo+stacking into the deterministic priced quote
`{:subtotal :discount :tax :total :codes}` with `total = subtotal - discount
+ tax`. Explicit tax policy: tax on GROSS per-line amounts (discount reduces
payable, not tax base) — documented for the determinism contract. This quote
is the value the Phase-3 order flow will carry. quote suite 13/13; total
112/112.
- 2026-06-07 — `stack.sx` (**Phase 2 complete**): stacking precedence as a
separate selection layer (precedence NOT in the rules, per the miniKanren
design rule). Exclusivity = unordered code pairs; `valid-stackings` enumerates
every legal subset of applicable promos (powerset excluded combos);
`best-stacking` is the deterministic max-total-discount selection (stable on
ties). `stacking-by-totalo` is the best-price backward query ("which legal
stacking yields total D?"). Member vs guest falls out of applicable-promos.
stack suite 16/16; total 99/99.
- 2026-06-07 — `promo.sx` (Phase 2 piece 1): four promo types as tagged tuples
`(:percent code class bps)`/`(:fixed code threshold amount)`/`(:bundle code sku
n)`/`(:member code class bps)`. Per-promo discount is pure integer arithmetic;
`promo-discounto`/`promo-applieso` enumerate (code, amount) relationally —
forward ("which apply?") and backward ("which code yields 2000?" → run* over
applieso). `applicable-promos`/`promo-amount-for` deterministic helpers. promo
amounts via `project` to ground the membero-bound promo. promo suite 17/17;
total 83/83. Next: stacking precedence + best-price (stack.sx).
- 2026-06-06 — `api.sx` (**Phase 1 complete**): session facade
`{:ctx :cart}` with `commerce-add`/`-remove`/`-set-qty`/`-total`/`-count`/
`-lines`, `commerce-can-add?` catalog validation, `commerce-explain` per-line
audit breakdown ({:sku :variant :qty :unit :extended :tax}), and a
`commerce-checkout` Phase-3 stub. api suite 12/12; total 66/66.
- 2026-06-06 — `price.sx`: deterministic `cart-subtotal` (Σ unit×qty, variant
delta defaults 0) + jurisdiction-relational tax. `taxo` facts indexed by
(jurisdiction, product-class, customer-class)→bps, queried multidirectionally;
`apply-bps` rounds half-up with integer arithmetic only. `cart-total` returns
`{:subtotal :discounts :tax :total}` (discounts 0 until Phase 2), reproducible
from (context, cart). `=` does structural dict equality (order-independent), so
total dicts compare directly. price suite 20/20; total 54/54.
- 2026-06-06 — `cart.sx`: cart as an ordered list of (sku variant qty) lines.
Pure ops `cart-add` (merges same line / appends), `cart-set-qty` (0 removes),
`cart-remove`, plus `cart-qty`/`cart-count`/`cart-skus`/`cart-empty?`.
`cart-lineo` is the relational view (membero over the cart) — forward and
backward. cart suite 18/18; total 34/34.
- 2026-06-06 — `catalog.sx`: catalog snapshot (products/variants/stock as fact
tuples) + multidirectional accessor relations (`producto`/`varianto`/`stocko`,
derived `priceo`/`classo`/`unit-priceo`) + deterministic `catalog-price`/
`-class`/`-has?` helpers. `conformance.sh` harness + scoreboard. catalog suite
16/16. Gotcha: minikanren `run-n` macro binds `s` internally — query vars must
avoid `s`; tests compare reified results with `=` (not `equal?`, which fails on
reified lists). Money = integer minor units throughout.
## Phase 3 flow-integration notes (for the next iteration)
Order flow = checkboxes 1-2 (reserve→pay→fulfil as a flow-on-sx flow + webhook
resume). Design is settled; the remaining work is mechanical but slow to iterate.
- **flow is the Scheme-on-SX guest layer**, not the SX/minikanren host. Load
order: `lib/guest/{lex,reflective/env,reflective/quoting}` + `lib/scheme/{parser,
eval,runtime}` + `lib/flow/{spec,store,remote,host,api}`. Confirmed it coexists
with the minikanren + persist stacks in one sx_server process.
- **Driver API (SX side):** `(flow-make-env)` builds the env once; `(flow-run-in
env "<scheme-src>")` evaluates a Scheme program string. Flows/driving are all
Scheme: `(flow/start flow input)`, `(flow/resume id val)`, `(flow/pending)`,
`(flow/status id)`, `(flow/result id)`. Host ABI (host.sx): `(request kind
payload)` suspends with a typed envelope; `(flow-host-requests)` lists pending.
- **Settled design:** the Scheme flow carries ONLY the order-id (a string) and is
pure orchestration: `(defflow ordf (lambda (oid) (begin (request 'reserve oid)
(request 'payment oid) (request 'fulfil oid))))`. All IO/ledger work stays in
SX — the SX driver services each request by appending to the persist ledger
(ledger.sx) and resuming with a marker. Payment stays suspended until the
webhook calls flow/resume. Marshalling is trivial (just strings).
- **GOTCHA (cost me a turn):** `flow-make-env` returns a large/likely-cyclic env
object; returning it from `(eval "...")` makes the harness serializer hang (got
exit 0 with NO epoch-2 output). NEVER return the env — wrap as `(begin (define
env (flow-make-env)) :ok)`. Structure the flow suite like `lib/flow/conformance.sh`:
load once, build env once, run all assertions in ONE process returning small
count values. Budget a long timeout (flow's own suite uses 540s); env build is
~150s CPU and balloons under sibling-agent CPU contention.
## Blockers
(loop fills this in)
(none)