Finally figured out how I want atoms to work

orchid-extension/src/other_system.rs

@@ -0,0 +1,37 @@
+use std::marker::PhantomData;
+
+use orchid_api::atom::Atom;
+use orchid_api::expr::ExprTicket;
+use orchid_api::proto::ExtMsgSet;
+use orchid_api::system::SysId;
+use orchid_base::reqnot::ReqNot;
+
+use crate::atom::{decode_atom, AtomCard, ForeignAtom};
+use crate::system::SystemCard;
+
+pub struct SystemHandle<C: SystemCard> {
+  pub(crate) _card: PhantomData<C>,
+  pub(crate) id: SysId,
+  pub(crate) reqnot: ReqNot<ExtMsgSet>,
+}
+impl<T: SystemCard> SystemHandle<T> {
+  pub(crate) fn new(id: SysId, reqnot: ReqNot<ExtMsgSet>) -> Self {
+    Self { _card: PhantomData, id, reqnot }
+  }
+  pub fn id(&self) -> SysId { self.id }
+  pub fn wrap_atom<A: AtomCard<Owner = T>>(
+    &self,
+    api: Atom,
+    ticket: ExprTicket,
+  ) -> Result<ForeignAtom<A>, Atom> {
+    if api.owner == self.id {
+      if let Some(value) = decode_atom::<A>(&T::default(), &api) {
+        return Ok(ForeignAtom { ticket, sys: self.clone(), value, api });
+      }
+    }
+    Err(api)
+  }
+}
+impl<T: SystemCard> Clone for SystemHandle<T> {
+  fn clone(&self) -> Self { Self { reqnot: self.reqnot.clone(), _card: PhantomData, id: self.id } }
+}