partway towards commands

I got very confused and started mucking about with "spawn" when in fact all I needed was the "inline" extension type in orcx that allows the interpreter to expose custom constants.

orchid-api/src/expr.rs

@@ -4,7 +4,7 @@ use std::num::NonZeroU64;
 use orchid_api_derive::{Coding, Hierarchy};
 use orchid_api_traits::Request;
 
-use crate::{Atom, ExtHostNotif, ExtHostReq, Location, OrcError, SysId, TStrv};
+use crate::{Atom, ExtHostNotif, ExtHostReq, LocalAtom, Location, OrcError, SysId, TStrv};
 
 /// An arbitrary ID associated with an expression on the host side. Incoming
 /// tickets always come with some lifetime guarantee, which can be extended with
@@ -65,8 +65,7 @@ pub enum ExpressionKind {
 	/// Insert a new atom in the tree. When the clause is used in the const tree,
 	/// the atom must be trivial. This is always a newly constructed atom, if you
 	/// want to reference an existing atom, use the corresponding [ExprTicket].
-	/// Because the atom is newly constructed, it also must belong to this system.
-	NewAtom(Atom),
+	NewAtom(LocalAtom),
 	/// A reference to a constant
 	Const(TStrv),
 	/// A static runtime error.
@@ -123,7 +122,7 @@ pub enum ExprNotif {
 
 #[derive(Clone, Debug, Coding, Hierarchy)]
 #[extends(ExprReq, ExtHostReq)]
-pub struct Create(pub Expression);
+pub struct Create(pub SysId, pub Expression);
 impl Request for Create {
 	type Response = ExprTicket;
 }