Time: the date of law, a rule window, and an edition

Law answers as of a date. The same case before a norm’s entry into force and after it gets different answers, and neither is a mistake. Dates are the corpus’s most frequent literal: over eight thousand in 443 packages out of 508 (measured 05.09.2026). And the most frequent source of the “why is law silent” question: the rule is written correctly, the facts are fed, yet the answer is NEITHER, because on this date the rule does not yet exist.

This page holds three ways to date a norm and one axis they all check against. The Archive of Veliky Ustin adopts a new edition of the rules from 2027.

Arxo Law

language "law.core" version "0.2";
package tutorial.archive version "0.4.0";
namespace "urn:law:tutorial:archive";

entity Person;

source ARCHIVE_RULES {
    kind municipal_act;
    jurisdiction VELIKY_USTIN;
    number "2026-14";
}

edition ARCHIVE_RULES_2026_RU of ARCHIVE_RULES {
    language ru;
    officiality official;
    adopted @2026-01-15;
    in_force [@2026-02-01, infinity);
}

edition ARCHIVE_RULES_2027_RU of ARCHIVE_RULES {
    language ru;
    officiality official;
    adopted @2026-11-20;
    in_force [@2027-01-01, infinity);
}

fragment ARCHIVE_RULES_2027_P6 in ARCHIVE_RULES_2027_RU {
    kind paragraph;
    locator "paragraph/6";
    text ru official """Исследователь, состоящий в реестре, вправе заказать оцифровку документа.
""";
    content_hash "sha256:aeb29654149aeea7af992a44563af55ae16c9bde3177074ad72334bd3d201756";
}

relation in_researcher_registry(p: Person) kind institutional;
relation accredited(p: Person) kind institutional;
relation briefing_required(p: Person) kind institutional;
relation may_order_digitization(p: Person) kind institutional;
relation reader_card_issued(p: Person, on: Date) kind empirical { key(p); }
relation card_reissue_required(p: Person) kind institutional;

The quoted fragment reads: “A researcher listed in the registry may order digitization of a document.”

The axis everything looks at

A case context holds four axes, none taken from the system clock: legal_time — the date on which the applicable law is selected; decision_time — the moment the answer is issued; knowledge_time — the boundary of data known to the system; timezone — the zone. All dated things on this page check against the first axis. An answer issued in March 2027 on a June-2026 event counts under June-2026 law — that is the difference between decision_time and legal_time, and confusing them is costly.

A scenario test sets the axes for each scenario separately, so the page speaks in pairs below: one case, two dates of law.

A rule window

From 1 January 2027, rare-collections room access requires a briefing first. The norm gets its own validity window — the effective clause.

Arxo Law

rule BriefingRequired2027 strict {
    effective [@2027-01-01, infinity);
    for p: Person;
    when in_researcher_registry(p);
    then briefing_required(p);
}

legal_time	briefing_required	applied(BriefingRequired2027)
2026-06-01	NEITHER	no
2027-06-01	TRUE_ONLY	yes

effective is an applicability condition, not a premise. Before the window the rule did not “fire with a false condition”: it took no part in the computation at all, and why_not will name it a candidate with the NOT_APPLICABLE status, not “condition not established”. The distinction shows in the test too: the applied(…) observation answers “no” before the window and “yes” inside it.

The first test is from the page you are reading, byte for byte:

Arxo Law

test "до окна effective правило не участвует" {
    given {
        context {
            decision_time @2027-03-01T09:00:00+05:00;
            knowledge_time @2027-03-01T09:00:00+05:00;
            legal_time @2026-06-01;
            timezone "Asia/Almaty";
        }
        assert in_researcher_registry(entity_ref("urn:tutorial:ivanova")) {
            id "assert-reg";
            origin case_input;
        }
    }
    evaluate truth(briefing_required(entity_ref("urn:tutorial:ivanova")));
    expect truth_status == NEITHER;
    expect evaluation_status == COMPUTED;
    expect not applied(BriefingRequired2027);
}

The test name reads: “Before the effective window the rule takes no part.”

Note: decision_time in both scenarios is March 2027, and only legal_time changes. The answer date does not select the law.

A rule dated by edition

The right to order digitization appears in the 2027 edition. The norm has no effective of its own: the anchor leads to that edition’s fragment, and its in_force decides the rule’s participation.

Arxo Law

@source(ARCHIVE_RULES_2027_P6)
rule DigitizationOrder strict {
    for p: Person;
    when in_researcher_registry(p);
    then may_order_digitization(p);
}

legal_time	may_order_digitization	Document
2026-06-01	NEITHER	issue EDITION_NOT_APPLICABLE
2027-06-01	TRUE_ONLY	—

This is the corpus’s ordinary form: in_force [@…, infinity) on the edition and rules without their own window, dated by anchors. A rule is removed only when all editions it is anchored to are inapplicable on the date of law; the document carries one issue per edition, and why_not answers with the same NOT_APPLICABLE. An edition with neither in_force nor another applicability event dates nothing: “law is not dated” is an answer, not “not in force”.

When to choose what. effective on a rule — when one article enters into force apart from the act: the Social Code of RK holds nine such windows from 1998 to 2023. An edition — when the act is dated as a whole; then a window on the rule is spare and will sooner or later diverge from in_force.

A date in the body

The third way dates no norm at all but compares a fact’s date. Tickets issued before the 2026 rules entered into force are subject to reissue: this is a condition on a fact, and it lives in the body.

Arxo Law

rule OldCardReissue strict {
    for p: Person;
    for on: Date;
    when reader_card_issued(p, on) and on < @2026-02-01;
    then card_reissue_required(p);
}

Ticket issued	card_reissue_required
2025-12-01	TRUE_ONLY
2026-03-01	NEITHER

legal_time is irrelevant here: the rule applies on any date of law, while the fact’s date decides. So the corpus also writes retroactivity: by comparing the event date in the body, not by a window.

A fact is dated too

A norm is dated by law, a fact by the world. A case statement carries a valid window: when it holds of the legal state. An accreditation issued from 2027 does not enter supports in June 2026.

Output

assert accredited(entity_ref("urn:tutorial:ivanova")) {
    id "assert-acc-2027";
    origin case_input;
    valid [@2027-01-01, infinity);
}

legal_time	accredited	Document
2026-06-01	NEITHER	issue ASSERTION_OUTSIDE_VALID
2027-06-01	TRUE_ONLY	—

The window checks against the same legal_time axis; evaluation_status stays COMPUTED, because the computation took place — just without this fact. Two more fact times, observed and recorded, answer another question: when observed and when entered into the system. They compare with nothing but each other.

Three compiler refusals

A rule holds one window. A second effective in the same block is a refusal, not an intersection:

Output

error LDC-E1329: повторная клауза `effective` в правиле — не более одной на
блок (§94, E-0114)

The diagnostic reads: “repeated effective clause in a rule — at most one per block”.

A window boundary is a date, an instant, or infinity. The compiler does not accept a name instead of a date, however telling it seems to you:

Output

error LDC-E1305: граница effective — дата/instant или infinity

The diagnostic reads: “an effective boundary is a date/instant or infinity”.

Date and Instant are different kinds, and they cannot be compared. Replace the date in OldCardReissue with the instant @2026-02-01T00:00:00+05:00:

Output

error LDC-E2108: «<»: несравнимые виды Date и Instant — §57/§48 требуют
совпадения видов, неявных конверсий нет

The diagnostic reads: “‘<’: incomparable kinds Date and Instant — kinds must match, no implicit conversions”.

No implicit conversions on purpose: midnight of 1 February in Almaty and in Greenwich are different instants, and which of them is “the date” is a policy question, not an arithmetic one. Write the threshold in the argument’s kind: date to date, instant to instant. All three refusals belong to the language.

Why law stays silent

When a norm yields NEITHER on any case, dates are the first thing to check. There are three: the case’s legal_time, the rule’s effective, and the in_force of the edition the @source leads to. A stub edition with a future in_force removes all rules anchored to it at once, and check will not tell: statically all is correct; removal happens at runtime. why_not names the candidate and its status — that is the first tool, not the last.

Next

The effective window says when a norm applies. When the norm’s addressee must act — by which date to perform, within which term to answer — is another machine: the calendar, the terms-counting policy, and the deadline query; the tutorial on terms is devoted to it. And in the duty tutorial the window will appear on the position itself: the “from 2027” milestone stays in the rule’s effective, while the aim’s window counts from the event. Both pages are in the track plan but not yet written.

The exercise for this page is /tutorials/exercise-time/.