final case class Repeat[-I, +O, +E](alterand: Stage[I, O, E]) extends Decorator[I, O, E]
A decorator that keeps re-applying the inner stage (following the continuations its h8io.stages.Evolution selects for h8io.stages.Status.Success) until the stage signals completion or an error.
The loop is implemented with @tailrec so it does not grow the stack. The loop continues as long as the inner stage yields h8io.stages.Status.Success. It stops on h8io.stages.Status.Complete: if there are no errors the status is converted back to Success; if there are errors, the Complete status is preserved.
In every branch the continuation of the inner stage is selected by the status the inner stage itself produced, and never by the status Repeat reports to the enclosing pipeline — the two differ, since an error-free Complete is absorbed into a Success. For the same reason the returned evolution is a h8io.stages.base.ConstEvolution: the status the enclosing pipeline evolves Repeat with belongs to that pipeline, not to the inner stage, and must not be passed inwards. Symmetrically, a skipped Repeat skips its inner stage and selects the inner continuation on the neutral Status.Success. The returned ConstEvolution keeps the inner evolution's dispose as its own: per the h8io.stages.Evolution contract, the inner evolution stays the terminal cleanup handle for the generation constructed here until that generation runs.
Repeat is useful for driving stages like h8io.stages.std.Countdown that signal "batch complete" via Status.Complete and should be repeated as a whole unit.
Returns this stage's Evolution without consuming an input.
Returns this stage's Evolution without consuming an input.
Called instead of apply whenever the stage takes part in a run but has nothing to process: the upstream yielded no output, or a binary operator excluded this branch. The evolution must be the one the stage would have returned had it run. Like apply, skip() may perform side effects — a decorator, for instance, may advance or release the inner stage it owns.
Composes this stage with that, feeding this stage's output into it. See the ''Composition'' section above for what happens when there is no output to feed.
Composes this stage with that, feeding this stage's output into it. See the ''Composition'' section above for what happens when there is no output to feed.