LDC-Q2010 — The label reader takes one or two arguments, not three

What it means

Labels name the human-readable titles attached to a node, optionally in one language. The reader therefore takes the node plus at most one language: a third argument has no meaning, so the engine stops the query instead of ignoring it.

Drop the extra argument. To read labels in every language, pass the node alone.

Example

Both queries below run against this package:

Arxo Law

language "law.core" version "0.2";
package demo.diagnostics version "0.1.0";
namespace "urn:law:demo:diagnostics";

entity Applicant;
relation resident(a: Applicant) kind institutional;
relation permit_eligible(a: Applicant) kind institutional;

rule PermitEligibility strict {
    for a: Applicant;
    when resident(a);
    then permit_eligible(a);
}

Three arguments are one too many:

LawQL

from r in rules select labels(r.id, r.id, r.id)

Fix

LawQL

from r in rules select r

Engine message

The engine reports this in its own wording:

Output

LDC-Q2010: labels(node[, lang]) expects 1–2 arguments.

Related

• Questions to the engine — the helpers a query can call.
• LDC-Q2009 — the general wrong-argument-count refusal.