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executor-nu

In-process Nushell embedding. Workflow steps expressed as Nushell evaluate inside the executor's own process — no child shell, no interpreter startup cost — and produce typed values back.

Interface

Engine::new() builds a full Nushell engine state (language commands plus the shell command set). Two entry points:

• eval(script) — evaluate a script, return a Nushell Value.
• eval_with_run_context(script, run) — the same, with the run context injected first.

Failures cross the boundary as executor_core::WorkflowError; Nushell ShellErrors are converted at the edge, never leaked.

Run context: $env.TING_RUN

RunContext carries run_id, workflow, step, plus optional extras (arbitrary nested JSON). Before evaluation it is serialized to JSON, converted into a native Nushell record (value::json_to_value preserves field order; unknown JSON variants become strings), and bound as $env.TING_RUN. A step script therefore reads its run identity as ordinary Nushell:

$env.TING_RUN.run_id
$env.TING_RUN.workflow

Linked-stream combinators

The embedded engine keeps the standard Nushell command set intact, so the linked-stream combinators run natively against real pipelines — verified by the crate's own tests:

• par-each — concurrent per-item evaluation
• reduce — fold a stream into one value
• chunks — fixed-size grouping of a stream
• zip — pair two streams
• window — sliding windows over a stream

These are the composition primitives workflow steps use for fan-out and aggregation; the crate adds no custom commands of its own.