language nodes

Language nodes are the escape hatch: kind: python, kind: r, kind: javascript, or kind: sql. The YAML declares slots and outputs; the language owns the computation.

Use one when the built-in nodes would hide the real logic, or when you need a package, query, model, visualization, custom file output, or multiple named outputs.

Slot contract

Field	Required	Notes
`kind`	yes	`python`, `r`, `javascript`, or `sql`. Legacy `kind: script` also carries `language`.
`source`	run-time required	Project-relative script/query path. The editor can create an unfinished node, but a run needs a source file.
`in`	no	Named slot map: slot name to `nodeId`, `nodeId.output`, or `params.name`.
`out`	no	Declared output map or list. Omit for the manifest/default output.
`entrypoint`	no	Function/export name for languages that need one.

Inputs and outputs

in is a named map from function/query slot to a node ref, named output ref, or params.name scalar. Empty in is allowed for ingress scripts.

out can declare multiple named outputs. When omitted, the node uses the language manifest or the default output.

Choosing the language

Use SQL for DuckDB-backed joins, scans, and relational transforms.
Use Python/R for statistics, modeling, plotting, or libraries Rime should not rebuild as core nodes.
Use JavaScript when the project already has JS utilities or when output shaping is easier near web/report code.

Runtime failure modes

A language node without source fails at run time.
If script execution is disabled or no executor is registered for the language, the node fails with NODE_UNSUPPORTED.
Multi-output declarations must match what the script actually returns.

Named-slot example

specification_version: "2.1"

params:
  threshold: { type: float, default: 0.5 }

nodes:
  - id: features
    kind: python
    source: scripts/features.py
    in:
      cohort: upstream_node
      threshold: params.threshold
    out:
      default: table
    entrypoint: run

Python language nodes - pandas-based transforms
R language nodes - data.frame/tibble-style transforms
JavaScript language nodes - defineNode and row-array transforms
SQL language nodes - DuckDB-backed transforms