Named Flows

A single Story can run several independent execution contexts at once — named flows. Each flow has its own position, call stack, and output, while sharing the story’s globals and visit counts. They’re how you model a background conversation, a parallel subplot, or a side channel that advances on its own.

#![allow(unused)]
fn main() {
extern crate brink_format;
extern crate brink_runtime;
use brink_format::DefinitionId;
use brink_runtime::{RuntimeError, Story};
fn demo(story: &mut Story, entry_point: DefinitionId, index: usize) -> Result<(), RuntimeError> {
story.spawn_flow("background", entry_point)?;              // start a flow at an address
let lines = story.continue_flow_maximally("background")?;  // -> Vec<Line>
story.choose_flow("background", index)?;                   // pick a choice in that flow
story.destroy_flow("background")?;                         // tear it down
let _ = lines;
Ok(())
}
}

spawn_flow takes a DefinitionId — the compiled address of a knot or stitch, not a name. flow_names() lists the currently active named flows.

The default, unnamed flow is the one driven by continue_single / continue_maximally / choose. The *_flow variants target a flow by name and otherwise behave identically — same Line results, same choice protocol.

Errors

• UnknownFlow — referenced a flow name that isn’t active.
• FlowAlreadyExists — spawn_flow with a name that’s already in use.

See Reference › Errors for the full list.

For engine integration, bevy-brink exposes each flow as an entity with its own components rather than name-keyed lookups — see Bevy › Spawning & Driving Flows.