Cleaned up atoms

- Atoms now use MFBI to distinguish between thin and owned atoms.
- Introduced TryFromExpr and ToExpr (formerly ToClause) from the old FFI
- Standardized on Bottom being a ProjErr, which means that there will be no RTErr

orchid-extension/src/atom_thin.rs

@@ -0,0 +1,46 @@
+use std::{any::type_name, fmt, io::Write};
+
+use orchid_api::atom::LocalAtom;
+use orchid_api_traits::{Coding, Decode, Encode};
+use typeid::ConstTypeId;
+
+use crate::{atom::{get_info, AtomCard, AtomFactory, AtomInfo, Atomic, AtomicFeaturesImpl, AtomicVariant, ErrorNotCallable}, expr::{bot, ExprHandle, GenExpr}, system::SysCtx};
+
+pub struct ThinVariant;
+impl AtomicVariant for ThinVariant {}
+impl<A: ThinAtom + Atomic<Variant = ThinVariant>> AtomicFeaturesImpl<ThinVariant> for A {
+  fn _factory(self) -> AtomFactory {
+    AtomFactory::new(move |sys| {
+      let mut buf = get_info::<A>(sys.dyn_card()).0.enc_vec();
+      self.encode(&mut buf);
+      LocalAtom { drop: false, data: buf }
+    })
+  }
+  fn _info() -> &'static AtomInfo {
+    &const {
+      AtomInfo {
+        tid: ConstTypeId::of::<Self>(),
+        decode: |mut b| Box::new(Self::decode(&mut b)),
+        call: |mut b, ctx, extk| Self::decode(&mut b).call(ExprHandle::from_args(ctx, extk)),
+        call_ref: |mut b, ctx, extk| Self::decode(&mut b).call(ExprHandle::from_args(ctx, extk)),
+        handle_req: |mut b, ctx, req, rep| Self::decode(&mut b).handle_req(ctx, Decode::decode(req), rep),
+        same: |mut b1, ctx, mut b2| Self::decode(&mut b1).same(ctx, &Self::decode(&mut b2)),
+        drop: |mut b1, _| eprintln!("Received drop signal for non-drop atom {:?}", Self::decode(&mut b1)),
+      }
+    }
+  }
+}
+
+pub trait ThinAtom: AtomCard<Data = Self> + Coding + fmt::Debug {
+  #[allow(unused_variables)]
+  fn call(&self, arg: ExprHandle) -> GenExpr { bot(ErrorNotCallable) }
+  #[allow(unused_variables)]
+  fn same(&self, ctx: SysCtx, other: &Self) -> bool {
+    eprintln!(
+      "Override ThinAtom::same for {} if it can be generated during parsing",
+      type_name::<Self>()
+    );
+    false
+  }
+  fn handle_req(&self, ctx: SysCtx, req: Self::Req, rep: &mut (impl Write + ?Sized));
+}