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

`type.foreign_value`

Value written as another language writes it.

Area 2, Values and types; not declinable; the next step is usually the agent's.

There is no null, nil, undefined or None: a missing value is none, and Python's True and False are true and false.

example

type ProductName = Text {    min_length: 1}function no_subtitle() -> ProductName? {    return null}

jadpo checkcheck failed: 1 error, 1 file

error Jadpo writes none, not null

--> main.jadpo:6:12

  |6 |     return null  |            ^^^^ write `none`

reason: null is a missing value in JavaScript, Java, C# and Kotlin; Jadpo writes it none.
next: Use none instead of null (agent)
rule: type.foreign_value
help: https://jadpo.dev/docs/errors/type.foreign_value

Markdown for agents: /docs/errors/type.foreign_value.md.Built from Jadpo main at aee2e8f.