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-api-traits/src/hier2.rs

@@ -1,30 +0,0 @@
-pub trait TBool {}
-pub struct TTrue;
-impl TBool for TTrue {}
-pub struct TFalse;
-impl TBool for TFalse {}
-
-/// Implementation picker for a tree node
-///
-/// Note: This technically allows for the degenerate case
-/// ```
-/// struct MyType;
-/// impl TreeRolePicker for MyType {
-///   type IsLeaf = TTrue;
-///   type IsRoot = TTrue;
-/// }
-/// ```
-/// This isn't very useful because it describes a one element sealed hierarchy.
-pub trait TreeRolePicker {
-  type IsLeaf: TBool;
-  type IsRoot: TBool;
-}
-
-pub trait Extends: TreeRolePicker<IsRoot = TFalse> {
-  type Parent: TreeRolePicker<IsLeaf = TFalse>;
-}
-
-pub trait Inherits<T> {}
-
-// impl<T> Inherits<T, 0> for T {}
-impl<T: Extends, This> Inherits<T::Parent> for This where This: Inherits<T> {}

orchid-api-traits/src/hierarchy.rs

@@ -1,8 +1,3 @@
-/// [Hierarchy] implementation key. The two implementors of this trait are
-/// [Base] and [Subtype]. These types are assigned to [InHierarchy::Role] to
-/// select the implementation of [Hierarchy].
-pub trait HierarchyRole {}
-
 /// A type-level boolean suitable to select conditional trait implementations.
 /// Implementors are [True] and [False]
 pub trait TLBool {}
@@ -13,17 +8,6 @@ impl TLBool for TLTrue {}
 pub struct TLFalse;
 impl TLBool for TLFalse {}
 
-/// Assign this type to [InHierarchy::Role] and implement [Descendant] to create
-/// a subtype. These types can be upcast to their parent type, conditionally
-/// downcast from it, and selected for [Descendant::Parent] by other types.
-pub struct Subtype;
-impl HierarchyRole for Subtype {}
-/// Assign this type to [InHierarchy::Role] to create a base type. These types
-/// are upcast only to themselves, but they can be selected in
-/// [Descendant::Parent].
-pub struct Base;
-impl HierarchyRole for Base {}
-
 /// A type that implements [Hierarchy]. Used to select implementations of traits
 /// on the hierarchy
 pub trait InHierarchy: Clone {

orchid-api-traits/src/lib.rs

@@ -6,7 +6,6 @@ mod relations;
 pub use coding::{Coding, Decode, Encode};
 pub use helpers::{encode_enum, read_exact, write_exact};
 pub use hierarchy::{
-  Base, Extends, HierarchyRole, InHierarchy, Subtype, TLBool, TLFalse, TLTrue, UnderRoot,
-  UnderRootImpl,
+  Extends, InHierarchy, TLBool, TLFalse, TLTrue, UnderRoot,
 };
 pub use relations::{Channel, MsgSet, Request};