A known symbol that needs importing

symbol.needsImport

Message

'<name>' is a function of the built-in '<module>' module; import it with (import! &self <module>) to use it.

or, when the name is defined in another workspace file:

'<name>' is defined in '<path>'; import it with (import! &self "<path>") to use it.

What it means

An unknown head is valid data in MeTTa, so this is a hint, not an error. It fires when the head is exactly a name that an import would make available: a built-in module's export (json, catalog, fileio) or a symbol another file in the workspace already defines. Until you import it, the head stays an unknown symbol and is treated as data.

How to fix it

Import the module or the file that defines it (the quick fix inserts the import!).

!(json-encode (1 2 3))   ; symbol.needsImport: run (import! &self json) to use json-encode

Controlled by the metta.diagnostics.undefinedFunctions setting.