Struct FlowStack 

pub struct FlowStack { /* private fields */ }

The runtime above the DAG: the main flow plus its digressions, with push-on-trigger and resume-on-completion (MVP: nesting depth 1).

While a digression is active, governance — tool admission, postures/grounds, explain() — delegates to the active layer, and the main flow’s marking is untouched, so Resume::Previous resumes exactly where it left off. Driven by State/guards (model-free, deterministic).

Implementations

impl FlowStack

pub fn current(&self) -> &FlowMonitor

The monitor currently driving — the active overlay if any, else the main flow.

pub fn active_overlay(&self) -> Option<&str>

The name of the active digression, if one is suspending the main flow.

pub fn is_complete(&self) -> bool

Whether the conversation is finished (main complete, or a Terminate digression ran).

pub fn on_turn(&mut self, state: &State)

Advance one turn. Enters a triggered digression (suspending the main flow), advances an active digression and resumes when it completes, or advances the main flow.

pub fn on_tool_ok(&mut self, tool: &str, state: &State)

Record a successful tool call against the active layer.

pub fn admits_tool(&self, tool: &str, state: &State) -> Result<(), String>

Whether tool is admitted right now (delegates to the active layer).

pub fn explain(&self, state: &State) -> FlowExplanation

Explain the active layer’s control-plane state.