Compose facts from two cases

Intention

I want to join selected facts from two cases while keeping their origin.

Composing facts is separate from importing norms.

Correct formFrozen execution sceneBoundary

Incorrect form and why it stays silent

You cannot overlay a different payload with the same id on top of an HR record.

Incorrect form

assert not eligible(entity_ref("urn:recipe:n-package:07:p")) {
    id "assert-eligible-record"; origin case_input;
}

When a positive record with the same full StableId is attached, composition fails with LDC-E1360.

Correct form

The composition stand in resources/07-compose/ contains a manifest, a lock, and two exported snapshots. They are generated by resources/generate.py; no outside bytes are borrowed. Program, snapshot declarations, and case:

Arxo Law

language "law.core" version "0.2";
package recipes.n.r07 version "0.1.0";
namespace "urn:recipe:n-package:07";

entity Person;
relation eligible(p: Person);
relation verified(p: Person);
relation granted(p: Person);
rule Grant strict { for p: Person; when eligible(p) and verified(p); then granted(p); }
snapshot HR "snapshots/hr.json";
snapshot Audit "snapshots/audit.json";
case Combined {
    context {
        legal_time @2026-09-13;
        decision_time @2026-09-13T09:00:00+05:00;
        knowledge_time @2026-09-13T09:00:00+05:00;
        timezone "Asia/Almaty";
    }
    use HR { record "urn:recipe:n-package:07#assert-eligible-record"; }
    use Audit { record "urn:recipe:n-package:07#assert-verified-record"; }
}

Frozen execution scene

Facts	Question	Answer
eligible from HR, verified from Audit	granted(p)	TRUE_ONLY

First both evaluators compose one case; then the test runner asks both. The table is not replaced by hand-rewritten asserts.

composed case yields both premises

Arxo Law

test "composed case yields both premises" {
    given {
        context {
            legal_time @2026-09-13;
            decision_time @2026-09-13T09:00:00+05:00;
            knowledge_time @2026-09-13T09:00:00+05:00;
            timezone "Asia/Almaty";
        }

    }
    evaluate truth(granted(entity_ref("urn:recipe:n-package:07:p")));
    expect truth_status == TRUE_ONLY;
    expect applied(Grant);
}

Counterfactual

teaches adds a negative payload for an existing id in Combined and runs lower-case inside a copy of the pinned package. The expected result is exactly LDC-E1360, not an error about a missing snapshot.

Boundary

Importing a program does not carry facts. A snapshot supplies only exported records; origin is preserved. Equal ids with equal payloads fold; when payloads differ there is no “last record wins” rule.

Pitfall

Two payloads of one StableId are rejected with LDC-E1360. The scenario below reduces the example to two facts and one conflicting record, keeping both sides of the composition.