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LDC-Q2008 — The query calls a function the language does not define

For LLMs5 sections

What it means

Section titled “What it means”

Expressions in a query can call a small fixed set of helpers for working with rows — shortening names, reading labels, testing membership. Any other name is not a call the engine can run, so the query stops at it, and the message lists the helpers that do exist.

Use one of the listed helpers, or move the computation out of the query: derive the value with a rule in the package instead.

Example

Section titled “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);
}

No helper carries this name:

LawQL
from r in rules select nosuchfunc(r.id)

Fix

Section titled “Fix”
LawQL
from r in rules select r

Engine message

Section titled “Engine message”

The engine reports this in its own wording:

Output
LDC-Q2008: unknown function 'nosuchfunc'. Hint: available: anchor, labels, short, contains, overlaps, starts_with, ends_with, position, derivation
Section titled “Related”

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