sim_kernel/env/
fork.rs

1//! Seeded-context forking: [`Cx::fork_from_seed`].
2
3use crate::Cx;
4
5impl Cx {
6    /// Forks a fresh, independently-seated context from `self` used as a seed.
7    ///
8    /// The fork is a brand-new [`Cx`] (with its own [`GrantSeat`] identity, its
9    /// own stores and ledgers) that carries a copy of the seed's evaluation
10    /// surface: the eval policy and factory it is built from, plus the seed's
11    /// environment, behavior registry, source registry, promotion-search limits,
12    /// control policy, and macro expander. The seed's granted capabilities are
13    /// re-granted into the fork through the fork's own host seat, so the fork
14    /// starts with the same authority without sharing the seed's mutable state.
15    ///
16    /// This generalizes the per-consumer `clone_stream_cx` / `clone_server_cx`
17    /// helpers into one kernel primitive; it is a strict superset (it copies the
18    /// control policy and macro expander that only some of those helpers did).
19    ///
20    /// The data substrate (datum/fact/handle stores, effect ledger, load claims,
21    /// diagnostics) is intentionally *not* copied: those are per-context runtime
22    /// state, and a fork begins with the fresh empty stores of [`Cx::new`].
23    ///
24    /// [`GrantSeat`]: crate::GrantSeat
25    pub fn fork_from_seed(&self, handle_seed: crate::HandleSeed) -> Cx {
26        let (mut fork, seat) =
27            Cx::new_seated(self.eval_policy_ref(), self.factory_ref(), handle_seed);
28        *fork.env_mut() = self.env().clone();
29        *fork.registry_mut() = self.registry().clone();
30        *fork.sources_mut() = self.sources().clone();
31        fork.set_promotion_search_limits(self.promotion_search_limits());
32        fork.set_control_policy(self.control_policy_ref());
33        if let Some(expander) = self.macro_expander_ref() {
34            fork.set_macro_expander(expander);
35        }
36        for capability in self.capabilities().iter() {
37            seat.grant(&mut fork, capability.clone())
38                .expect("fork seat grants into its own Cx");
39        }
40        fork
41    }
42}
sim_kernel/env/fork.rs

sim_kernel/env/
fork.rs
