in midst of refactor

orchid-api/src/atom.rs

@@ -0,0 +1,91 @@
+use orchid_api_derive::{Coding, Hierarchy};
+use orchid_api_traits::Request;
+
+use crate::expr::{Expr, ExprTicket};
+use crate::proto::{ExtHostReq, HostExtNotif, HostExtReq};
+use crate::system::SysId;
+
+pub type AtomData = Vec<u8>;
+
+/// An atom representation that can be serialized and sent around. Atoms
+/// represent the smallest increment of work.
+#[derive(Clone, Debug, Hash, PartialEq, Eq, Coding)]
+pub struct Atom {
+  /// Instance ID of the system that created the atom
+  pub owner: SysId,
+  /// Indicates whether the owner should be notified when this atom is dropped.
+  /// Construction is always explicit and atoms are never cloned.
+  ///
+  /// Atoms with `drop == false` are also known as trivial, they can be
+  /// duplicated and stored with no regard to expression lifetimes. NOTICE
+  /// that this only applies to the atom. If it's referenced with an
+  /// [ExprTicket], the ticket itself can still expire.
+  ///
+  /// Notice also that the atoms still expire when the system is dropped, and
+  /// are not portable across instances of the same system, so this doesn't
+  /// imply that the atom is serializable.
+  pub drop: bool,
+  /// Data stored in the atom. This could be a key into a map, or the raw data
+  /// of the atom if it isn't too big.
+  pub data: AtomData,
+}
+
+/// Attempt to apply an atom as a function to an expression
+#[derive(Clone, Debug, Hash, PartialEq, Eq, Coding, Hierarchy)]
+#[extends(AtomReq, HostExtReq)]
+pub struct CallRef(pub Atom, pub ExprTicket);
+impl Request for CallRef {
+  type Response = Expr;
+}
+
+/// Attempt to apply an atom as a function, consuming the atom and enabling the
+/// library to reuse its datastructures rather than duplicating them. This is an
+/// optimization over [CallRef] followed by [AtomDrop].
+#[derive(Clone, Debug, Hash, PartialEq, Eq, Coding, Hierarchy)]
+#[extends(AtomReq, HostExtReq)]
+pub struct FinalCall(pub Atom, pub ExprTicket);
+impl Request for FinalCall {
+  type Response = Expr;
+}
+
+/// Determine whether two atoms are identical for the purposes of macro
+/// application. If a given atom is never generated by macros or this relation
+/// is difficult to define, the module can return false
+#[derive(Clone, Debug, Hash, PartialEq, Eq, Coding, Hierarchy)]
+#[extends(AtomReq, HostExtReq)]
+pub struct AtomSame(pub Atom, pub Atom);
+impl Request for AtomSame {
+  type Response = bool;
+}
+
+/// A request blindly routed to the system that provides an atom.
+#[derive(Clone, Debug, Hash, PartialEq, Eq, Coding, Hierarchy)]
+#[extends(AtomReq, HostExtReq)]
+pub struct Fwded(pub Atom, pub Vec<u8>);
+impl Request for Fwded {
+  type Response = Vec<u8>;
+}
+
+#[derive(Clone, Debug, Hash, PartialEq, Eq, Coding, Hierarchy)]
+#[extends(ExtHostReq)]
+pub struct Fwd(pub Atom, pub Vec<u8>);
+impl Request for Fwd {
+  type Response = Vec<u8>;
+}
+
+/// Notification that an atom is being dropped because its associated expression
+/// isn't referenced anywhere. This should have no effect if the atom's `drop`
+/// flag is false.
+#[derive(Clone, Debug, Hash, PartialEq, Eq, Coding, Hierarchy)]
+#[extends(HostExtNotif)]
+pub struct AtomDrop(pub Atom);
+
+#[derive(Clone, Debug, Hash, PartialEq, Eq, Coding, Hierarchy)]
+#[extends(HostExtReq)]
+#[extendable]
+pub enum AtomReq {
+  CallRef(CallRef),
+  FinalCall(FinalCall),
+  AtomSame(AtomSame),
+  Fwded(Fwded),
+}