EffectList<O, T, E> is a stream: a list whose next cell is produced by an effect, so reading it may perform operations, such as reading the next chunk of a file. module.f.mjs builds one, and types.ts holds the types.
| Function | Builds |
|---|---|
empty() | the end of the stream |
nonEmpty(first, tail) | a cell |
fromList(list) | a stream over a plain List |
transduce(machine)(emit)(source) runs the shared Transducer lifecycle over an effect list. Each nonempty output chunk is passed to the effectful emit callback before the next input is pulled. The final flush reaches the sink before the effect returns the terminal summary. run(machine)(source) returns the summary while discarding output.
The machine's initial step runs before any source pull. Initial or later completion stops reading immediately, including on an unbounded source, and does not call end again. Source and sink failures propagate through the effect's error channel; a domain failure carried by the machine remains its summary value. A failing source does not trigger EOF finalization, and a failing flush prevents a successful summary.
Output is delivered directly to the sink instead of collecting a second list. This matters for the effect representation: pure cells are strict, while real commands suspend. The driver loops through pure spans without growing the call stack and leaves source and sink commands suspended for their runner.
A failure ends the stream. The error belongs to the cell, not to an item, so a producer that cannot deliver fails the effect that would have produced the next cell, and step propagates it to the consumer without a check per item.
Node's readChunks answers an EffectList of byte chunks, read as the consumer pulls them (node).