Jadpo is experimental and not ready for production. These docs follow the compiler's main branch as of 5 Nov 2026. What's built · Install 0.3.0

ReferenceErrors

Errors Reads and writes · rule

`query.aggregate_field`

Aggregate cannot be worked out over this field.

Area 6, Reads and writes; not declinable; the next step is usually the agent's.

example

type Fine = Money {}entity Loan {    id: Uuid    fine: Fine}type FinesOwed = Output {    owed: Money}query fines_owed() -> FinesOwed {    from: Loan    aggregate: {        owed: sum(Loan.fine)    }}

jadpo checkcheck failed: 1 error, 1 file

error sum adds up money in one currency, and Loan.fine's type doesn't fix one

--> main.jadpo:15:19

   |15 |         owed: sum(Loan.fine)   |                   ^^^^^^^^^ `Fine`

reason: Amounts in two currencies don't add up (currency_mismatch), and a sum of no records needs a currency for its zero, so the field's type fixes its currency: Fine doesn't.
next: Give Fine a currency: (agent)
rule: query.aggregate_field
help: https://jadpo.dev/docs/errors/query.aggregate_field

Markdown for agents: /docs/errors/query.aggregate_field.md.Built from Jadpo main at aee2e8f.