Cut down on macro nonsense

- InertAtomic replaced atomic_inert! for improved tooling support
- atomic_defaults! is easier to type out than to explain in a docstring
- Changed rustfmt config to better support tiny functions such as as_any

.github/workflows/rust.yml

@@ -26,4 +26,4 @@ jobs:
     - name: Clippy
       run: cargo clippy
     - name: Formatting
-      run: cargo fmt --check
+      run: cargo fmt +nightly --check

orchid.code-workspace

@@ -29,6 +29,9 @@
 		"rust-analyzer.showUnlinkedFileNotification": false,
 		"rust-analyzer.checkOnSave": true,
 		"rust-analyzer.check.command": "clippy",
+		"rust-analyzer.rustfmt.extraArgs": [
+			"+nightly"
+		],
 		"files.associations": {
 			"*.mjsd": "markdown"
 		},

rust-toolchain.toml

@@ -1,2 +1,2 @@
 [toolchain]
-channel = "nightly"
+channel = "stable"

rustfmt.toml

@@ -13,6 +13,7 @@ normalize_comments = true
 wrap_comments = true
 overflow_delimited_expr = true
 use_small_heuristics = "Max"
+fn_single_line = true
 
 # literals
 hex_literal_case = "Lower"

src/bin/orcx.rs

@@ -61,9 +61,7 @@ impl Args {
     Ok(())
   }
 
-  pub fn chk_proj(&self) -> Result<(), String> {
-    self.chk_dir_main()
-  }
+  pub fn chk_proj(&self) -> Result<(), String> { self.chk_dir_main() }
 }
 
 pub fn to_vname(data: &str, i: &Interner) -> VName {

src/error/import_all.rs

@@ -15,9 +15,7 @@ pub struct ImportAll {
   pub offender_mod: Rc<VName>,
 }
 impl ProjectError for ImportAll {
-  fn description(&self) -> &str {
-    "a top-level glob import was used"
-  }
+  fn description(&self) -> &str { "a top-level glob import was used" }
   fn message(&self) -> String {
     format!("{} imports *", self.offender_mod.iter().join("::"))
   }

src/error/no_targets.rs

@@ -16,7 +16,5 @@ impl ProjectError for NoTargets {
     "No targets were specified for layer parsing"
   }
 
-  fn positions(&self) -> BoxedIter<ErrorPosition> {
-    box_empty()
-  }
+  fn positions(&self) -> BoxedIter<ErrorPosition> { box_empty() }
 }

src/error/parse_error_with_tokens.rs

@@ -16,9 +16,7 @@ pub struct ParseErrorWithTokens {
   pub error: Rc<dyn ProjectError>,
 }
 impl ProjectError for ParseErrorWithTokens {
-  fn description(&self) -> &str {
-    self.error.description()
-  }
+  fn description(&self) -> &str { self.error.description() }
   fn message(&self) -> String {
     format!(
       "Failed to parse code: {}\nTokenized source for context:\n{}",
@@ -26,7 +24,5 @@ impl ProjectError for ParseErrorWithTokens {
       self.tokens.iter().map(|t| t.to_string()).join(" "),
     )
   }
-  fn positions(&self) -> BoxedIter<ErrorPosition> {
-    self.error.positions()
-  }
+  fn positions(&self) -> BoxedIter<ErrorPosition> { self.error.positions() }
 }

src/error/project_error.rs

@@ -20,9 +20,7 @@ pub trait ProjectError {
   /// A general description of this type of error
   fn description(&self) -> &str;
   /// A formatted message that includes specific parameters
-  fn message(&self) -> String {
-    self.description().to_string()
-  }
+  fn message(&self) -> String { self.description().to_string() }
   /// Code positions relevant to this error. If you don't implement this, you
   /// must implement [ProjectError::one_position]
   fn positions(&self) -> BoxedIter<ErrorPosition> {
@@ -30,9 +28,7 @@ pub trait ProjectError {
   }
   /// Short way to provide a single location. If you don't implement this, you
   /// must implement [ProjectError::positions]
-  fn one_position(&self) -> Location {
-    unimplemented!()
-  }
+  fn one_position(&self) -> Location { unimplemented!() }
   /// Convert the error into an `Rc<dyn ProjectError>` to be able to
   /// handle various errors together
   fn rc(self) -> Rc<dyn ProjectError>

src/error/too_many_supers.rs

@@ -23,7 +23,5 @@ impl ProjectError for TooManySupers {
     )
   }
 
-  fn one_position(&self) -> Location {
-    self.location.clone()
-  }
+  fn one_position(&self) -> Location { self.location.clone() }
 }

src/facade/environment.rs

@@ -23,9 +23,7 @@ pub struct Environment<'a> {
 }
 impl<'a> Environment<'a> {
   /// Initialize a new environment
-  pub fn new(i: &'a Interner) -> Self {
-    Self { i, systems: Vec::new() }
-  }
+  pub fn new(i: &'a Interner) -> Self { Self { i, systems: Vec::new() } }
 
   /// Register a new system in the environment
   pub fn add_system<'b: 'a>(mut self, is: impl IntoSystem<'b> + 'b) -> Self {

src/facade/pre_macro.rs

@@ -116,9 +116,7 @@ pub struct MacroTimeout {
   limit: usize,
 }
 impl ProjectError for MacroTimeout {
-  fn description(&self) -> &str {
-    "Macro execution has not halted"
-  }
+  fn description(&self) -> &str { "Macro execution has not halted" }
 
   fn message(&self) -> String {
     format!(
@@ -128,7 +126,5 @@ impl ProjectError for MacroTimeout {
     )
   }
 
-  fn one_position(&self) -> Location {
-    self.location.clone()
-  }
+  fn one_position(&self) -> Location { self.location.clone() }
 }

src/facade/process.rs

@@ -84,7 +84,5 @@ impl ProjectError for MissingSymbol {
     )
   }
 
-  fn one_position(&self) -> Location {
-    self.location.clone()
-  }
+  fn one_position(&self) -> Location { self.location.clone() }
 }

src/facade/system.rs

@@ -59,9 +59,7 @@ impl ProjectError for MissingSystemCode {
       self.system.join("::")
     )
   }
-  fn positions(&self) -> BoxedIter<ErrorPosition> {
-    box_empty()
-  }
+  fn positions(&self) -> BoxedIter<ErrorPosition> { box_empty() }
 }
 
 /// Trait for objects that can be converted into a [System] in the presence

src/foreign/atom.rs

@@ -6,6 +6,7 @@ use dyn_clone::DynClone;
 use crate::interpreted::ExprInst;
 use crate::interpreter::{Context, RuntimeError};
 use crate::representations::interpreted::Clause;
+use crate::utils::ddispatch::Responder;
 use crate::Primitive;
 
 /// Information returned by [Atomic::run]. This mirrors
@@ -30,19 +31,18 @@ impl AtomicReturn {
 pub type AtomicResult = Result<AtomicReturn, RuntimeError>;
 
 /// Functionality the interpreter needs to handle a value
-pub trait Atomic: Any + Debug + DynClone
+pub trait Atomic: Any + Debug + DynClone + Responder
 where
   Self: 'static,
 {
-  /// A fully type-erased interface to issue a command to the unknown type
-  /// and see if it supports it
-  fn request(&self, _request: Box<dyn Any>) -> Option<Box<dyn Any>> {
-    None
-  }
-
   /// Casts this value to [Any] so that its original value can be salvaged
-  /// during introspection by other external code. There is no other way to
-  /// interact with values of unknown types at the moment.
+  /// during introspection by other external code.
+  ///
+  /// This function should be implemented in exactly one way:
+  ///
+  /// ```
+  /// fn as_any(&self) -> &dyn Any { self }
+  /// ```
   fn as_any(&self) -> &dyn Any;
 
   /// Attempt to normalize this value. If it wraps a value, this should report
@@ -81,31 +81,23 @@ impl Atom {
     Self(Box::new(data) as Box<dyn Atomic>)
   }
   /// Get the contained data
-  pub fn data(&self) -> &dyn Atomic {
-    self.0.as_ref() as &dyn Atomic
-  }
+  pub fn data(&self) -> &dyn Atomic { self.0.as_ref() as &dyn Atomic }
   /// Attempt to downcast contained data to a specific type
   pub fn try_cast<T: Atomic>(&self) -> Option<&T> {
     self.data().as_any().downcast_ref()
   }
   /// Test the type of the contained data without downcasting
-  pub fn is<T: 'static>(&self) -> bool {
-    self.data().as_any().is::<T>()
-  }
+  pub fn is<T: 'static>(&self) -> bool { self.data().as_any().is::<T>() }
   /// Downcast contained data, panic if it isn't the specified type
   pub fn cast<T: 'static>(&self) -> &T {
     self.data().as_any().downcast_ref().expect("Type mismatch on Atom::cast")
   }
   /// Normalize the contained data
-  pub fn run(&self, ctx: Context) -> AtomicResult {
-    self.0.run(ctx)
-  }
+  pub fn run(&self, ctx: Context) -> AtomicResult { self.0.run(ctx) }
 }
 
 impl Clone for Atom {
-  fn clone(&self) -> Self {
-    Self(dyn_clone::clone_box(self.data()))
-  }
+  fn clone(&self) -> Self { Self(dyn_clone::clone_box(self.data())) }
 }
 
 impl Debug for Atom {

src/foreign/cps_box.rs

@@ -4,11 +4,11 @@ use std::fmt::Debug;
 
 use trait_set::trait_set;
 
-use super::{Atomic, ExternFn, XfnResult};
+use super::{Atomic, ExternFn, InertAtomic, XfnResult};
 use crate::interpreted::{Clause, ExprInst};
 use crate::interpreter::{Context, HandlerRes};
 use crate::utils::pure_push::pushed_ref;
-use crate::{ConstTree, atomic_inert};
+use crate::ConstTree;
 
 trait_set! {
   /// A "well behaved" type that can be used as payload in a CPS box
@@ -34,9 +34,7 @@ impl<T: CPSPayload> CPSFn<T> {
   }
 }
 impl<T: CPSPayload> ExternFn for CPSFn<T> {
-  fn name(&self) -> &str {
-    "CPS function without argument"
-  }
+  fn name(&self) -> &str { "CPS function without argument" }
   fn apply(&self, arg: ExprInst, _ctx: Context) -> XfnResult {
     let payload = self.payload.clone();
     let continuations = pushed_ref(&self.continuations, arg);
@@ -93,7 +91,9 @@ impl<T: CPSPayload> CPSBox<T> {
   }
 }
 
-atomic_inert!(CPSBox(T:(CPSPayload)), typestr = "a CPS box");
+impl<T: CPSPayload> InertAtomic for CPSBox<T> {
+  fn type_str() -> &'static str { "a CPS box" }
+}
 
 /// Like [init_cps] but wrapped in a [ConstTree] for init-time usage
 pub fn const_cps<T: CPSPayload>(argc: usize, payload: T) -> ConstTree {

src/foreign/extern_fn.rs

@@ -55,9 +55,7 @@ pub trait ExternFn: DynClone {
 
 impl Eq for dyn ExternFn {}
 impl PartialEq for dyn ExternFn {
-  fn eq(&self, other: &Self) -> bool {
-    self.name() == other.name()
-  }
+  fn eq(&self, other: &Self) -> bool { self.name() == other.name() }
 }
 impl Hash for dyn ExternFn {
   fn hash<H: std::hash::Hasher>(&self, state: &mut H) {

src/foreign/inert.rs

@@ -0,0 +1,46 @@
+use std::any::Any;
+use std::fmt::Debug;
+use std::rc::Rc;
+
+use super::{AtomicResult, AtomicReturn, ExternError};
+#[allow(unused)] // for doc
+use crate::define_fn;
+use crate::foreign::Atomic;
+use crate::interpreted::{ExprInst, TryFromExprInst};
+use crate::interpreter::Context;
+use crate::systems::cast_exprinst::with_atomic;
+use crate::utils::ddispatch::{Request, Responder};
+
+/// A proxy trait that implements [Atomic] for blobs of data in Rust code that
+/// cannot be processed and always report inert. Since these are expected to be
+/// parameters of functions defined with [define_fn] it also automatically
+/// implements [TryFromExprInst] so that a conversion doesn't have to be
+/// provided in argument lists.
+pub trait InertAtomic: Debug + Clone + 'static {
+  /// Typename to be shown in the error when a conversion from [ExprInst] fails
+  fn type_str() -> &'static str;
+  /// Proxies to [Responder] so that you don't have to implmeent it manually if
+  /// you need it, but behaves exactly as the default implementation.
+  #[allow(unused_mut, unused_variables)] // definition should show likely usage
+  fn respond(&self, mut request: Request) {}
+}
+impl<T: InertAtomic> Responder for T {
+  fn respond(&self, request: Request) { self.respond(request) }
+}
+impl<T: InertAtomic> Atomic for T {
+  fn as_any(&self) -> &dyn Any { self }
+
+  fn run(&self, ctx: Context) -> AtomicResult {
+    Ok(AtomicReturn {
+      clause: self.clone().atom_cls(),
+      gas: ctx.gas,
+      inert: true,
+    })
+  }
+}
+
+impl<T: InertAtomic> TryFromExprInst for T {
+  fn from_exi(exi: &ExprInst) -> Result<Self, Rc<dyn ExternError>> {
+    with_atomic(exi, Self::type_str(), |a: &T| Ok(a.clone()))
+  }
+}

src/foreign/mod.rs

@@ -5,11 +5,13 @@
 mod atom;
 pub mod cps_box;
 mod extern_fn;
+mod inert;
 
 use std::rc::Rc;
 
 pub use atom::{Atom, Atomic, AtomicResult, AtomicReturn};
 pub use extern_fn::{ExternError, ExternFn, XfnResult};
+pub use inert::InertAtomic;
 
 pub use crate::representations::interpreted::Clause;
 

src/foreign_macros/atomic_defaults.rs

@@ -1,16 +0,0 @@
-#[allow(unused)] // for the doc comments
-use crate::foreign::Atomic;
-
-/// A macro that generates the straightforward, syntactically invariant part of
-/// implementing [Atomic].
-///
-/// Currently implements
-/// - [Atomic::as_any]
-#[macro_export]
-macro_rules! atomic_defaults {
-  () => {
-    fn as_any(&self) -> &dyn std::any::Any {
-      self
-    }
-  };
-}

src/foreign_macros/atomic_impl.rs

@@ -79,7 +79,7 @@ macro_rules! atomic_impl {
   };
   ($typ:ident, $next_phase:expr) => {
     impl $crate::foreign::Atomic for $typ {
-      $crate::atomic_defaults! {}
+      fn as_any(&self) -> &dyn std::any::Any { self }
 
       fn run(
         &self,

src/foreign_macros/atomic_inert.rs

@@ -1,76 +0,0 @@
-#[allow(unused)] // for the doc comments
-use std::any::Any;
-#[allow(unused)] // for the doc comments
-use std::fmt::Debug;
-
-#[allow(unused)] // for the doc comments
-use dyn_clone::DynClone;
-
-#[allow(unused)] // for the doc comments
-use crate::foreign::Atomic;
-
-/// Implement [Atomic] for a structure that cannot be transformed any further.
-/// This would be optimal for atomics encapsulating raw data. [Atomic] depends
-/// on [Any], [Debug] and [DynClone].
-/// 
-/// If the type in question is parametric, the angle brackets must be replaced
-/// by parentheses, and the contraints must be parenthesized, for conenient
-/// parsing. See the below example:
-/// 
-/// ```ignore
-/// use orchidlang::atomic_inert;
-/// 
-/// struct MyContainer<T, U: Clone, V: Eq + Hash>()
-/// 
-/// atomic_inert!( MyContainer(T, U:(Clone), V:(Eq + Hash)), "my container" );
-/// ```
-#[macro_export]
-macro_rules! atomic_inert {
-  ( $typ:ident $( (
-    $( $typevar:ident $( : (
-      $( $constraints:tt )*
-  ) )? ),+ ) )?
-  , typestr = $typename:expr $( , request = $reqhandler:expr )?) => {
-    impl $(< $($typevar : $( $($constraints)* + )? 'static ),+ >)? $crate::foreign::Atomic
-    for $typ $(< $($typevar),+ >)? {
-      $crate::atomic_defaults! {}
-
-      fn run(
-        &self,
-        ctx: $crate::interpreter::Context,
-      ) -> $crate::foreign::AtomicResult {
-        Ok($crate::foreign::AtomicReturn {
-          clause: self.clone().atom_cls(),
-          gas: ctx.gas,
-          inert: true,
-        })
-      }
-
-      $(
-        fn request(
-          &self,
-          request: Box<dyn std::any::Any>
-        ) -> Option<Box<dyn std::any::Any>> {
-          let lambda = $reqhandler;
-          lambda(request, self)
-        }
-      )?
-    }
-
-    impl $(< $($typevar : $( $($constraints)* + )? 'static ),+ >)?
-      TryFrom<&$crate::interpreted::ExprInst>
-    for $typ $(< $($typevar),+ >)? {
-      type Error = std::rc::Rc<dyn $crate::foreign::ExternError>;
-
-      fn try_from(
-        value: &$crate::interpreted::ExprInst,
-      ) -> Result<Self, Self::Error> {
-        $crate::systems::cast_exprinst::with_atom(
-          value,
-          $typename,
-          |a: &$typ $(< $($typevar),+ >)?| Ok(a.clone()),
-        )
-      }
-    }
-  };
-}

src/foreign_macros/atomic_redirect.rs

@@ -7,9 +7,7 @@ use crate::atomic_impl;
 macro_rules! atomic_redirect {
   ($typ:ident) => {
     impl AsRef<$crate::foreign::RcExpr> for $typ {
-      fn as_ref(&self) -> &Clause {
-        &self.0
-      }
+      fn as_ref(&self) -> &Clause { &self.0 }
     }
     impl From<(&Self, $crate::foreign::RcExpr)> for $typ {
       fn from((old, clause): (&Self, Clause)) -> Self {
@@ -19,9 +17,7 @@ macro_rules! atomic_redirect {
   };
   ($typ:ident, $field:ident) => {
     impl AsRef<$crate::interpreted::ExprInst> for $typ {
-      fn as_ref(&self) -> &$crate::interpreted::ExprInst {
-        &self.$field
-      }
+      fn as_ref(&self) -> &$crate::interpreted::ExprInst { &self.$field }
     }
     impl From<(&Self, $crate::interpreted::ExprInst)> for $typ {
       #[allow(clippy::needless_update)]

src/foreign_macros/externfn_impl.rs

@@ -25,9 +25,7 @@ use crate::{atomic_impl, atomic_redirect};
 macro_rules! externfn_impl {
   ($typ:ident, $next_atomic:expr) => {
     impl $crate::foreign::ExternFn for $typ {
-      fn name(&self) -> &str {
-        stringify!($typ)
-      }
+      fn name(&self) -> &str { stringify!($typ) }
       fn apply(
         &self,
         arg: $crate::interpreted::ExprInst,

src/foreign_macros/mod.rs

@@ -1,6 +1,4 @@
-mod atomic_defaults;
 mod atomic_impl;
-mod atomic_inert;
 mod atomic_redirect;
 mod define_fn;
 mod externfn_impl;

src/foreign_macros/write_fn_step.rs

@@ -107,6 +107,7 @@ macro_rules! write_fn_step {
       $( $arg: $typ, )*
       expr_inst: $crate::interpreted::ExprInst,
     }
+    impl $crate::utils::ddispatch::Responder for $name {}
     $crate::atomic_redirect!($name, expr_inst);
     $crate::atomic_impl!($name);
     $crate::externfn_impl!(
@@ -136,6 +137,7 @@ macro_rules! write_fn_step {
       expr_inst: $crate::interpreted::ExprInst,
     }
     $crate::atomic_redirect!($name, expr_inst);
+    impl $crate::utils::ddispatch::Responder for $name {}
     $crate::atomic_impl!(
       $name,
       |Self{ $($arg, )* expr_inst }: &Self, _| {
@@ -157,6 +159,6 @@ macro_rules! write_fn_step {
     }
   };
   (@CONV $locxname:expr) => {
-    ($locxname).try_into()?
+    ($locxname).downcast()?
   };
 }

src/interner/multitype.rs

@@ -18,9 +18,7 @@ pub struct Interner {
 }
 impl Interner {
   /// Create a new interner
-  pub fn new() -> Self {
-    Self { interners: RefCell::new(HashMap::new()) }
-  }
+  pub fn new() -> Self { Self { interners: RefCell::new(HashMap::new()) } }
 
   /// Intern something
   pub fn i<Q: ?Sized + Eq + Hash + ToOwned>(&self, q: &Q) -> Tok<Q::Owned>
@@ -62,9 +60,7 @@ impl Interner {
 }
 
 impl Default for Interner {
-  fn default() -> Self {
-    Self::new()
-  }
+  fn default() -> Self { Self::new() }
 }
 
 /// Get or create an interner for a given type.

src/interner/token.rs

@@ -27,9 +27,7 @@ impl<T: Eq + Hash + Clone + 'static> Tok<T> {
       .expect("Pointer can always be cast to nonzero")
   }
   /// Cast into usize
-  pub fn usize(&self) -> usize {
-    self.id().into()
-  }
+  pub fn usize(&self) -> usize { self.id().into() }
   ///
   pub fn assert_comparable(&self, other: &Self) {
     let iref = self.interner.as_ptr() as usize;
@@ -50,9 +48,7 @@ impl<T: Eq + Hash + Clone + 'static> Tok<Vec<Tok<T>>> {
 impl<T: Eq + Hash + Clone + 'static> Deref for Tok<T> {
   type Target = T;
 
-  fn deref(&self) -> &Self::Target {
-    self.data.as_ref()
-  }
+  fn deref(&self) -> &Self::Target { self.data.as_ref() }
 }
 
 impl<T: Eq + Hash + Clone + 'static + Debug> Debug for Tok<T> {

src/interpreter/error.rs

@@ -17,9 +17,7 @@ pub enum RuntimeError {
 }
 
 impl From<Rc<dyn ExternError>> for RuntimeError {
-  fn from(value: Rc<dyn ExternError>) -> Self {
-    Self::Extern(value)
-  }
+  fn from(value: Rc<dyn ExternError>) -> Self { Self::Extern(value) }
 }
 
 impl Display for RuntimeError {

src/interpreter/handler.rs

@@ -20,9 +20,7 @@ pub struct HandlerTable<'a> {
 }
 impl<'a> HandlerTable<'a> {
   /// Create a new [HandlerTable]
-  pub fn new() -> Self {
-    Self { handlers: HashMap::new() }
-  }
+  pub fn new() -> Self { Self { handlers: HashMap::new() } }
 
   /// Add a handler function to interpret a type of atom and decide what happens
   /// next. This function can be impure.

src/parse/context.rs

@@ -40,13 +40,7 @@ impl<'a> Clone for ParsingContext<'a> {
 }
 
 impl Context for ParsingContext<'_> {
-  fn interner(&self) -> &Interner {
-    self.interner
-  }
-  fn file(&self) -> Rc<VName> {
-    self.file.clone()
-  }
-  fn ops(&self) -> &[Tok<String>] {
-    self.ops
-  }
+  fn interner(&self) -> &Interner { self.interner }
+  fn file(&self) -> Rc<VName> { self.file.clone() }
+  fn ops(&self) -> &[Tok<String>] { self.ops }
 }

src/parse/errors.rs

@@ -13,15 +13,11 @@ pub struct LineNeedsPrefix {
   pub entry: Entry,
 }
 impl ProjectError for LineNeedsPrefix {
-  fn description(&self) -> &str {
-    "This linetype requires a prefix"
-  }
+  fn description(&self) -> &str { "This linetype requires a prefix" }
   fn message(&self) -> String {
     format!("{} cannot appear at the beginning of a line", self.entry)
   }
-  fn one_position(&self) -> Location {
-    self.entry.location()
-  }
+  fn one_position(&self) -> Location { self.entry.location() }
 }
 
 #[derive(Debug)]
@@ -30,9 +26,7 @@ pub struct UnexpectedEOL {
   pub entry: Entry,
 }
 impl ProjectError for UnexpectedEOL {
-  fn description(&self) -> &str {
-    "The line ended abruptly"
-  }
+  fn description(&self) -> &str { "The line ended abruptly" }
 
   fn message(&self) -> String {
     "The line ends unexpectedly here. In Orchid, all line breaks outside \
@@ -40,21 +34,15 @@ impl ProjectError for UnexpectedEOL {
       .to_string()
   }
 
-  fn one_position(&self) -> Location {
-    self.entry.location()
-  }
+  fn one_position(&self) -> Location { self.entry.location() }
 }
 
 pub struct ExpectedEOL {
   pub location: Location,
 }
 impl ProjectError for ExpectedEOL {
-  fn description(&self) -> &str {
-    "Expected the end of the line"
-  }
-  fn one_position(&self) -> Location {
-    self.location.clone()
-  }
+  fn description(&self) -> &str { "Expected the end of the line" }
+  fn one_position(&self) -> Location { self.location.clone() }
 }
 
 #[derive(Debug)]
@@ -85,9 +73,7 @@ impl ProjectError for ExpectedName {
     }
   }
 
-  fn one_position(&self) -> Location {
-    self.entry.location()
-  }
+  fn one_position(&self) -> Location { self.entry.location() }
 }
 
 #[derive()]
@@ -115,16 +101,15 @@ impl ProjectError for Expected {
       &[] => return "Unsatisfiable expectation".to_string(),
       [only] => only.to_string(),
       [a, b] => format!("either {a} or {b}"),
-      [variants @ .., last] =>
-        format!("any of {} or {last}", variants.iter().join(", ")),
+      [variants @ .., last] => {
+        format!("any of {} or {last}", variants.iter().join(", "))
+      },
     };
     let or_name = if self.or_name { " or a name" } else { "" };
     format!("Expected {list}{or_name} but found {}", self.found)
   }
 
-  fn one_position(&self) -> Location {
-    self.found.location()
-  }
+  fn one_position(&self) -> Location { self.found.location() }
 }
 
 pub struct ReservedToken {
@@ -135,13 +120,9 @@ impl ProjectError for ReservedToken {
     "A token reserved for future use was found in the code"
   }
 
-  fn message(&self) -> String {
-    format!("{} is a reserved token", self.entry)
-  }
+  fn message(&self) -> String { format!("{} is a reserved token", self.entry) }
 
-  fn one_position(&self) -> Location {
-    self.entry.location()
-  }
+  fn one_position(&self) -> Location { self.entry.location() }
 }
 
 pub struct BadTokenInRegion {
@@ -157,9 +138,7 @@ impl ProjectError for BadTokenInRegion {
     format!("{} cannot appear in {}", self.entry, self.region)
   }
 
-  fn one_position(&self) -> Location {
-    self.entry.location()
-  }
+  fn one_position(&self) -> Location { self.entry.location() }
 }
 
 pub struct NotFound {
@@ -171,25 +150,17 @@ impl ProjectError for NotFound {
     "A specific lexeme was expected but not found in the given range"
   }
 
-  fn message(&self) -> String {
-    format!("{} was expected", self.expected)
-  }
+  fn message(&self) -> String { format!("{} was expected", self.expected) }
 
-  fn one_position(&self) -> Location {
-    self.location.clone()
-  }
+  fn one_position(&self) -> Location { self.location.clone() }
 }
 
 pub struct LeadingNS {
   pub location: Location,
 }
 impl ProjectError for LeadingNS {
-  fn description(&self) -> &str {
-    ":: can only follow a name token"
-  }
-  fn one_position(&self) -> Location {
-    self.location.clone()
-  }
+  fn description(&self) -> &str { ":: can only follow a name token" }
+  fn one_position(&self) -> Location { self.location.clone() }
 }
 
 pub struct MisalignedParen {
@@ -199,12 +170,8 @@ impl ProjectError for MisalignedParen {
   fn description(&self) -> &str {
     "Parentheses (), [] and {} must always pair up"
   }
-  fn message(&self) -> String {
-    format!("This {} has no pair", self.entry)
-  }
-  fn one_position(&self) -> Location {
-    self.entry.location()
-  }
+  fn message(&self) -> String { format!("This {} has no pair", self.entry) }
+  fn one_position(&self) -> Location { self.entry.location() }
 }
 
 pub struct NamespacedExport {
@@ -214,9 +181,7 @@ impl ProjectError for NamespacedExport {
   fn description(&self) -> &str {
     "Exports can only refer to unnamespaced names in the local namespace"
   }
-  fn one_position(&self) -> Location {
-    self.location.clone()
-  }
+  fn one_position(&self) -> Location { self.location.clone() }
 }
 
 pub struct GlobExport {
@@ -226,9 +191,7 @@ impl ProjectError for GlobExport {
   fn description(&self) -> &str {
     "Exports can only refer to concrete names, globstars are not allowed"
   }
-  fn one_position(&self) -> Location {
-    self.location.clone()
-  }
+  fn one_position(&self) -> Location { self.location.clone() }
 }
 
 pub struct LexError {
@@ -237,9 +200,7 @@ pub struct LexError {
   pub file: VName,
 }
 impl ProjectError for LexError {
-  fn description(&self) -> &str {
-    "An error occured during tokenization"
-  }
+  fn description(&self) -> &str { "An error occured during tokenization" }
   fn positions(&self) -> BoxedIter<ErrorPosition> {
     let file = self.file.clone();
     Box::new(self.errors.iter().map(move |s| ErrorPosition {

src/parse/lexer.rs

@@ -40,9 +40,7 @@ impl Entry {
     )
   }
 
-  pub fn location(&self) -> Location {
-    self.location.clone()
-  }
+  pub fn location(&self) -> Location { self.location.clone() }
 
   pub fn range(&self) -> Range<usize> {
     self.location.range().expect("An Entry can only have a known location")
@@ -84,9 +82,7 @@ impl Display for Entry {
 // }
 
 impl AsRef<Location> for Entry {
-  fn as_ref(&self) -> &Location {
-    &self.location
-  }
+  fn as_ref(&self) -> &Location { &self.location }
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
@@ -144,8 +140,9 @@ impl Display for Lexeme {
       Self::Module => write!(f, "module"),
       Self::Const => write!(f, "const"),
       Self::Macro => write!(f, "macro"),
-      Self::Operators(ops) =>
-        write!(f, "operators[{}]", Interner::extern_all(ops).join(" ")),
+      Self::Operators(ops) => {
+        write!(f, "operators[{}]", Interner::extern_all(ops).join(" "))
+      },
       Self::Placeh(Placeholder { name, class }) => match *class {
         PHClass::Scalar => write!(f, "${}", **name),
         PHClass::Vec { nonzero, prio } => {

src/pipeline/file_loader.rs

@@ -44,9 +44,7 @@ pub enum Loaded {
 }
 impl Loaded {
   /// Is the loaded item source code (not a collection)?
-  pub fn is_code(&self) -> bool {
-    matches!(self, Loaded::Code(_))
-  }
+  pub fn is_code(&self) -> bool { matches!(self, Loaded::Code(_)) }
 }
 
 /// Returned by any source loading callback

src/pipeline/source_loader/load_source.rs

@@ -87,8 +87,9 @@ fn load_abs_path_rec(
     // If the path is not within a file, load it as directory
     let coll = match get_source(abs_path) {
       Ok(Loaded::Collection(coll)) => coll,
-      Ok(Loaded::Code(_)) =>
-        unreachable!("split_name returned None but the path is a file"),
+      Ok(Loaded::Code(_)) => {
+        unreachable!("split_name returned None but the path is a file")
+      },
       Err(e) => {
         // todo: if this can actually be produced, return Err(ImportAll) instead
         let parent = abs_path.split_last().expect("import path nonzero").1;

src/pipeline/source_loader/preparse.rs

@@ -14,8 +14,8 @@ use crate::parse::{self, ParsingContext};
 use crate::representations::sourcefile::{FileEntry, MemberKind};
 use crate::representations::tree::{ModEntry, ModMember, Module};
 use crate::sourcefile::{FileEntryKind, Import, Member, ModuleBlock};
-use crate::utils::pure_push::pushed;
 use crate::utils::get_or::{get_or_default, get_or_make};
+use crate::utils::pure_push::pushed;
 use crate::{Location, Tok, VName};
 
 struct FileReport {

src/pipeline/source_loader/types.rs

@@ -69,8 +69,9 @@ impl Add for PreExtra {
   fn add(self, rhs: Self) -> Self::Output {
     match (self, rhs) {
       (alt, Self::Dir) | (Self::Dir, alt) => Ok(alt),
-      (Self::File(_) | Self::Submod(_), Self::File(_) | Self::Submod(_)) =>
-        panic!("Each file should be parsed once."),
+      (Self::File(_) | Self::Submod(_), Self::File(_) | Self::Submod(_)) => {
+        panic!("Each file should be parsed once.")
+      },
     }
   }
 }
@@ -79,8 +80,9 @@ impl Display for PreExtra {
   fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
     match self {
       Self::Dir => write!(f, "Directory"),
-      Self::File(PreFileExt { name, .. }) =>
-        write!(f, "File({}.orc)", Interner::extern_all(name).join("/")),
+      Self::File(PreFileExt { name, .. }) => {
+        write!(f, "File({}.orc)", Interner::extern_all(name).join("/"))
+      },
       Self::Submod(_) => write!(f, "Submodule"),
     }
   }

src/representations/ast.rs

@@ -57,9 +57,7 @@ impl<N: NameLike> Expr<N> {
 }
 
 impl<N: NameLike> AsRef<Location> for Expr<N> {
-  fn as_ref(&self) -> &Location {
-    &self.location
-  }
+  fn as_ref(&self) -> &Location { &self.location }
 }
 
 /// Visit all expression sequences including this sequence itself. Otherwise

src/representations/ast_to_postmacro.rs

@@ -50,9 +50,7 @@ impl ProjectError for Error {
       _ => self.description().to_string(),
     }
   }
-  fn one_position(&self) -> Location {
-    self.location.clone()
-  }
+  fn one_position(&self) -> Location { self.location.clone() }
 }
 
 /// Try to convert an expression from AST format to typed lambda
@@ -73,9 +71,7 @@ impl<'a> Context<'a> {
     Context { names: self.names.push(name) }
   }
 
-  fn new() -> Context<'static> {
-    Context { names: Substack::Bottom }
-  }
+  fn new() -> Context<'static> { Context { names: Substack::Bottom } }
 }
 
 /// Process an expression sequence

src/representations/interpreted.rs

@@ -13,6 +13,7 @@ use super::location::Location;
 use super::path_set::PathSet;
 use super::primitive::Primitive;
 use super::Literal;
+use crate::foreign::ExternError;
 use crate::Sym;
 
 /// An expression with metadata
@@ -45,6 +46,12 @@ impl Display for Expr {
 /// expression is not a literal
 pub struct NotALiteral;
 
+/// Types automatically convertible from an [ExprInst]
+pub trait TryFromExprInst: Sized {
+  /// Match and clone the value out of an [ExprInst]
+  fn from_exi(exi: &ExprInst) -> Result<Self, Rc<dyn ExternError>>;
+}
+
 /// A wrapper around expressions to handle their multiple occurences in
 /// the tree together
 #[derive(Clone)]
@@ -134,6 +141,13 @@ impl ExprInst {
       Clause::Constant(_) | Clause::LambdaArg | Clause::P(_) => None,
     })
   }
+
+  /// Convert into any type that implements [FromExprInst]. Calls to this
+  /// function are generated wherever a conversion is elided in an extern
+  /// function.
+  pub fn downcast<T: TryFromExprInst>(&self) -> Result<T, Rc<dyn ExternError>> {
+    T::from_exi(self)
+  }
 }
 
 impl Debug for ExprInst {
@@ -208,13 +222,9 @@ impl Display for Clause {
 }
 
 impl<T: Into<Literal>> From<T> for Clause {
-  fn from(value: T) -> Self {
-    Self::P(Primitive::Literal(value.into()))
-  }
+  fn from(value: T) -> Self { Self::P(Primitive::Literal(value.into())) }
 }
 
 impl<T: Into<Clause>> From<T> for ExprInst {
-  fn from(value: T) -> Self {
-    value.into().wrap()
-  }
+  fn from(value: T) -> Self { value.into().wrap() }
 }

src/representations/literal.rs

@@ -27,17 +27,11 @@ impl Debug for Literal {
 }
 
 impl From<NotNan<f64>> for Literal {
-  fn from(value: NotNan<f64>) -> Self {
-    Self::Num(value)
-  }
+  fn from(value: NotNan<f64>) -> Self { Self::Num(value) }
 }
 impl From<u64> for Literal {
-  fn from(value: u64) -> Self {
-    Self::Uint(value)
-  }
+  fn from(value: u64) -> Self { Self::Uint(value) }
 }
 impl From<String> for Literal {
-  fn from(value: String) -> Self {
-    Self::Str(value.into())
-  }
+  fn from(value: String) -> Self { Self::Str(value.into()) }
 }

src/representations/namelike.rs

@@ -25,13 +25,9 @@ pub trait NameLike: 'static + Clone + Eq + Hash + Debug {
 }
 
 impl NameLike for Sym {
-  fn to_strv(&self) -> Vec<String> {
-    self.extern_vec()
-  }
+  fn to_strv(&self) -> Vec<String> { self.extern_vec() }
 }
 
 impl NameLike for VName {
-  fn to_strv(&self) -> Vec<String> {
-    Interner::extern_all(self)
-  }
+  fn to_strv(&self) -> Vec<String> { Interner::extern_all(self) }
 }

src/representations/project.rs

@@ -25,9 +25,7 @@ pub enum ItemKind<N: NameLike> {
 }
 
 impl<N: NameLike> Default for ItemKind<N> {
-  fn default() -> Self {
-    Self::None
-  }
+  fn default() -> Self { Self::None }
 }
 
 #[derive(Debug, Clone, Default)]

src/representations/sourcefile.rs

@@ -84,8 +84,9 @@ pub enum MemberKind {
 impl Display for MemberKind {
   fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
     match self {
-      Self::Operators(opv) =>
-        write!(f, "operators[{}]", opv.iter().map(|t| &**t).join(" ")),
+      Self::Operators(opv) => {
+        write!(f, "operators[{}]", opv.iter().map(|t| &**t).join(" "))
+      },
       Self::Constant(c) => c.fmt(f),
       Self::Module(m) => m.fmt(f),
       Self::Rule(r) => r.fmt(f),
@@ -130,11 +131,13 @@ impl Display for FileEntryKind {
   fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
     match self {
       Self::Comment(s) => write!(f, "--[{s}]--"),
-      Self::Export(s) =>
-        write!(f, "export ::({})", s.iter().map(|t| &**t.0).join(", ")),
+      Self::Export(s) => {
+        write!(f, "export ::({})", s.iter().map(|t| &**t.0).join(", "))
+      },
       Self::Member(member) => write!(f, "{member}"),
-      Self::Import(i) =>
-        write!(f, "import ({})", i.iter().map(|i| i.to_string()).join(", ")),
+      Self::Import(i) => {
+        write!(f, "import ({})", i.iter().map(|i| i.to_string()).join(", "))
+      },
     }
   }
 }

src/representations/string.rs

@@ -25,9 +25,7 @@ impl Debug for OrcString {
 
 impl OrcString {
   /// Clone out the plain Rust [String]
-  pub fn get_string(&self) -> String {
-    self.as_str().to_owned()
-  }
+  pub fn get_string(&self) -> String { self.as_str().to_owned() }
 }
 
 impl Deref for OrcString {
@@ -48,15 +46,11 @@ impl Hash for OrcString {
 }
 
 impl From<String> for OrcString {
-  fn from(value: String) -> Self {
-    Self::Runtime(Rc::new(value))
-  }
+  fn from(value: String) -> Self { Self::Runtime(Rc::new(value)) }
 }
 
 impl From<Tok<String>> for OrcString {
-  fn from(value: Tok<String>) -> Self {
-    Self::Interned(value)
-  }
+  fn from(value: Tok<String>) -> Self { Self::Interned(value) }
 }
 
 impl PartialEq for OrcString {

src/representations/tree.rs

@@ -223,9 +223,7 @@ pub struct WalkError<'a> {
 }
 impl<'a> WalkError<'a> {
   /// Total length of the path represented by this error
-  pub fn depth(&self) -> usize {
-    self.prefix.len() + self.pos + 1
-  }
+  pub fn depth(&self) -> usize { self.prefix.len() + self.pos + 1 }
 
   /// Attach a location to the error and convert into trait object for reporting
   pub fn at(self, location: &Location) -> Rc<dyn ProjectError> {
@@ -263,15 +261,15 @@ impl ProjectError for WalkErrorWithLocation {
     let paths = Interner::extern_all(&self.path).join("::");
     let options = Interner::extern_all(&self.options).join(", ");
     match &self.kind {
-      ErrKind::Missing =>
-        format!("{paths} does not exist, options are {options}"),
-      ErrKind::NotModule =>
-        format!("{paths} is not a module, options are {options}"),
+      ErrKind::Missing => {
+        format!("{paths} does not exist, options are {options}")
+      },
+      ErrKind::NotModule => {
+        format!("{paths} is not a module, options are {options}")
+      },
       ErrKind::Private => format!("{paths} is private, options are {options}"),
     }
   }
 
-  fn one_position(&self) -> Location {
-    self.location.clone()
-  }
+  fn one_position(&self) -> Location { self.location.clone() }
 }

src/rule/matcher_vectree/shared.rs

@@ -56,9 +56,7 @@ pub enum AnyMatcher {
   Vec { left: Vec<ScalMatcher>, mid: VecMatcher, right: Vec<ScalMatcher> },
 }
 impl Matcher for AnyMatcher {
-  fn new(pattern: Rc<Vec<RuleExpr>>) -> Self {
-    mk_any(&pattern)
-  }
+  fn new(pattern: Rc<Vec<RuleExpr>>) -> Self { mk_any(&pattern) }
 
   fn apply<'a>(&self, source: &'a [RuleExpr]) -> Option<State<'a>> {
     any_match(self, source)
@@ -99,10 +97,12 @@ impl Display for VecMatcher {
         write!(f, "..${key}")
       },
       Self::Scan { left, sep, right, direction } => match direction {
-        Side::Left =>
-          write!(f, "Scan{{{left} <== {} <== {right}}}", sep.iter().join(" ")),
-        Side::Right =>
-          write!(f, "Scan{{{left} ==> {} ==> {right}}}", sep.iter().join(" ")),
+        Side::Left => {
+          write!(f, "Scan{{{left} <== {} <== {right}}}", sep.iter().join(" "))
+        },
+        Side::Right => {
+          write!(f, "Scan{{{left} ==> {} ==> {right}}}", sep.iter().join(" "))
+        },
       },
       Self::Middle { left, left_sep, mid, right_sep, right, .. } => {
         let left_sep_s = left_sep.iter().join(" ");
@@ -134,9 +134,7 @@ impl Display for AnyMatcher {
 /// vectorial placeholders and handles the scalars on leaves.
 pub struct VectreeMatcher(AnyMatcher);
 impl Matcher for VectreeMatcher {
-  fn new(pattern: Rc<Vec<RuleExpr>>) -> Self {
-    Self(AnyMatcher::new(pattern))
-  }
+  fn new(pattern: Rc<Vec<RuleExpr>>) -> Self { Self(AnyMatcher::new(pattern)) }
 
   fn apply<'a>(&self, source: &'a [RuleExpr]) -> Option<State<'a>> {
     self.0.apply(source)

src/rule/rule_error.rs

@@ -37,10 +37,12 @@ impl Display for RuleError {
   fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     match self {
       Self::Missing(key) => write!(f, "Key {key} not in match pattern"),
-      Self::ArityMismatch(key) =>
-        write!(f, "Key {key} used inconsistently with and without ellipsis"),
-      Self::Multiple(key) =>
-        write!(f, "Key {key} appears multiple times in match pattern"),
+      Self::ArityMismatch(key) => {
+        write!(f, "Key {key} used inconsistently with and without ellipsis")
+      },
+      Self::Multiple(key) => {
+        write!(f, "Key {key} appears multiple times in match pattern")
+      },
       Self::VecNeighbors(left, right) => write!(
         f,
         "Keys {left} and {right} are two vectorials right next to each other"

src/systems/asynch/system.rs

@@ -11,14 +11,14 @@ use ordered_float::NotNan;
 
 use crate::facade::{IntoSystem, System};
 use crate::foreign::cps_box::{init_cps, CPSBox};
-use crate::foreign::{Atomic, ExternError};
+use crate::foreign::{Atomic, ExternError, InertAtomic};
 use crate::interpreted::ExprInst;
 use crate::interpreter::HandlerTable;
 use crate::systems::codegen::call;
 use crate::systems::stl::Boolean;
 use crate::utils::poller::{PollEvent, Poller};
 use crate::utils::unwrap_or;
-use crate::{atomic_inert, define_fn, ConstTree, Interner};
+use crate::{define_fn, ConstTree, Interner};
 
 #[derive(Debug, Clone)]
 struct Timer {
@@ -45,7 +45,9 @@ impl Debug for CancelTimer {
 
 #[derive(Clone, Debug)]
 struct Yield;
-atomic_inert!(Yield, typestr = "a yield command");
+impl InertAtomic for Yield {
+  fn type_str() -> &'static str { "a yield command" }
+}
 
 /// Error indicating a yield command when all event producers and timers had
 /// exited
@@ -109,15 +111,11 @@ impl<'a> AsynchSystem<'a> {
   /// Obtain a message port for sending messages to the main thread. If an
   /// object is passed to the MessagePort that does not have a handler, the
   /// main thread panics.
-  pub fn get_port(&self) -> MessagePort {
-    MessagePort(self.sender.clone())
-  }
+  pub fn get_port(&self) -> MessagePort { MessagePort(self.sender.clone()) }
 }
 
 impl<'a> Default for AsynchSystem<'a> {
-  fn default() -> Self {
-    Self::new()
-  }
+  fn default() -> Self { Self::new() }
 }
 
 impl<'a> IntoSystem<'a> for AsynchSystem<'a> {

src/systems/cast_exprinst.rs

@@ -5,8 +5,8 @@ use std::rc::Rc;
 use ordered_float::NotNan;
 
 use super::assertion_error::AssertionError;
-use crate::foreign::{Atomic, ExternError};
-use crate::interpreted::Clause;
+use crate::foreign::{Atom, Atomic, ExternError};
+use crate::interpreted::{Clause, TryFromExprInst};
 use crate::representations::interpreted::ExprInst;
 use crate::representations::{Literal, OrcString};
 use crate::Primitive;
@@ -27,92 +27,66 @@ pub fn with_str<T>(
   x: &ExprInst,
   predicate: impl FnOnce(&OrcString) -> Result<T, Rc<dyn ExternError>>,
 ) -> Result<T, Rc<dyn ExternError>> {
-  with_lit(x, |l| {
-    if let Literal::Str(s) = l {
-      predicate(s)
-    } else {
-      AssertionError::fail(x.clone(), "a string")?
-    }
+  with_lit(x, |l| match l {
+    Literal::Str(s) => predicate(s),
+    _ => AssertionError::fail(x.clone(), "a string"),
   })
 }
 
-/// Like [with_lit] but also unwraps [Literal::Uint]
-pub fn with_uint<T>(
+/// If the [ExprInst] stores an [Atom], maps the predicate over it, otherwise
+/// raises a runtime error.
+pub fn with_atom<T>(
   x: &ExprInst,
-  predicate: impl FnOnce(u64) -> Result<T, Rc<dyn ExternError>>,
+  predicate: impl FnOnce(&Atom) -> Result<T, Rc<dyn ExternError>>,
 ) -> Result<T, Rc<dyn ExternError>> {
-  with_lit(x, |l| {
-    if let Literal::Uint(u) = l {
-      predicate(*u)
-    } else {
-      AssertionError::fail(x.clone(), "an uint")?
-    }
-  })
-}
-
-/// Like [with_lit] but also unwraps [Literal::Num]
-pub fn with_num<T>(
-  x: &ExprInst,
-  predicate: impl FnOnce(NotNan<f64>) -> Result<T, Rc<dyn ExternError>>,
-) -> Result<T, Rc<dyn ExternError>> {
-  with_lit(x, |l| {
-    if let Literal::Num(n) = l {
-      predicate(*n)
-    } else {
-      AssertionError::fail(x.clone(), "a float")?
-    }
+  x.inspect(|c| match c {
+    Clause::P(Primitive::Atom(a)) => predicate(a),
+    _ => AssertionError::fail(x.clone(), "an atom"),
   })
 }
 
 /// Tries to cast the [ExprInst] into the specified atom type. Throws an
 /// assertion error if unsuccessful, or calls the provided function on the
 /// extracted atomic type.
-pub fn with_atom<T: Atomic, U>(
+pub fn with_atomic<T: Atomic, U>(
   x: &ExprInst,
   inexact_typename: &'static str,
   predicate: impl FnOnce(&T) -> Result<U, Rc<dyn ExternError>>,
 ) -> Result<U, Rc<dyn ExternError>> {
-  x.inspect(|c| {
-    if let Clause::P(Primitive::Atom(a)) = c {
-      a.try_cast()
-        .map(predicate)
-        .unwrap_or_else(|| AssertionError::fail(x.clone(), inexact_typename))
-    } else {
-      AssertionError::fail(x.clone(), "an atom")
-    }
+  with_atom(x, |a| match a.try_cast() {
+    Some(atomic) => predicate(atomic),
+    _ => AssertionError::fail(x.clone(), inexact_typename),
   })
 }
 
 // ######## Automatically ########
 
-impl TryFrom<&ExprInst> for Literal {
-  type Error = Rc<dyn ExternError>;
-
-  fn try_from(value: &ExprInst) -> Result<Self, Self::Error> {
-    with_lit(value, |l| Ok(l.clone()))
+impl TryFromExprInst for Literal {
+  fn from_exi(exi: &ExprInst) -> Result<Self, Rc<dyn ExternError>> {
+    with_lit(exi, |l| Ok(l.clone()))
   }
 }
 
-impl TryFrom<&ExprInst> for OrcString {
-  type Error = Rc<dyn ExternError>;
-
-  fn try_from(value: &ExprInst) -> Result<Self, Self::Error> {
-    with_str(value, |s| Ok(s.clone()))
+impl TryFromExprInst for OrcString {
+  fn from_exi(exi: &ExprInst) -> Result<Self, Rc<dyn ExternError>> {
+    with_str(exi, |s| Ok(s.clone()))
   }
 }
 
-impl TryFrom<&ExprInst> for u64 {
-  type Error = Rc<dyn ExternError>;
-
-  fn try_from(value: &ExprInst) -> Result<Self, Self::Error> {
-    with_uint(value, Ok)
+impl TryFromExprInst for u64 {
+  fn from_exi(exi: &ExprInst) -> Result<Self, Rc<dyn ExternError>> {
+    with_lit(exi, |l| match l {
+      Literal::Uint(u) => Ok(*u),
+      _ => AssertionError::fail(exi.clone(), "an uint"),
+    })
   }
 }
 
-impl TryFrom<&ExprInst> for NotNan<f64> {
-  type Error = Rc<dyn ExternError>;
-
-  fn try_from(value: &ExprInst) -> Result<Self, Self::Error> {
-    with_num(value, Ok)
+impl TryFromExprInst for NotNan<f64> {
+  fn from_exi(exi: &ExprInst) -> Result<Self, Rc<dyn ExternError>> {
+    with_lit(exi, |l| match l {
+      Literal::Num(n) => Ok(*n),
+      _ => AssertionError::fail(exi.clone(), "a float"),
+    })
   }
 }

src/systems/io/bindings.rs

@@ -12,19 +12,19 @@ use crate::{ast, define_fn, ConstTree, Interner, Primitive};
 define_fn! {
   ReadString = |x| Ok(init_cps(3, IOCmdHandlePack{
     cmd: ReadCmd::RStr(SRead::All),
-    handle: x.try_into()?
+    handle: x.downcast()?
   }))
 }
 define_fn! {
   ReadLine = |x| Ok(init_cps(3, IOCmdHandlePack{
     cmd: ReadCmd::RStr(SRead::Line),
-    handle: x.try_into()?
+    handle: x.downcast()?
   }))
 }
 define_fn! {
   ReadBin = |x| Ok(init_cps(3, IOCmdHandlePack{
     cmd: ReadCmd::RBytes(BRead::All),
-    handle: x.try_into()?
+    handle: x.downcast()?
   }))
 }
 define_fn! {
@@ -72,7 +72,7 @@ define_fn! {
 define_fn! {
   Flush = |x| Ok(init_cps(3, IOCmdHandlePack {
     cmd: WriteCmd::Flush,
-    handle: x.try_into()?
+    handle: x.downcast()?
   }))
 }
 

src/systems/io/instances.rs

@@ -81,23 +81,23 @@ pub enum ReadResult {
 impl ReadResult {
   pub fn dispatch(self, succ: ExprInst, fail: ExprInst) -> Vec<ExprInst> {
     match self {
-      ReadResult::RBin(_, Err(e)) | ReadResult::RStr(_, Err(e)) =>
-        vec![call(fail, vec![wrap_io_error(e)]).wrap()],
+      ReadResult::RBin(_, Err(e)) | ReadResult::RStr(_, Err(e)) => {
+        vec![call(fail, vec![wrap_io_error(e)]).wrap()]
+      },
       ReadResult::RBin(_, Ok(bytes)) => {
         let arg = Binary(Arc::new(bytes)).atom_cls().wrap();
         vec![call(succ, vec![arg]).wrap()]
       },
-      ReadResult::RStr(_, Ok(text)) =>
-        vec![call(succ, vec![Literal::Str(text.into()).into()]).wrap()],
+      ReadResult::RStr(_, Ok(text)) => {
+        vec![call(succ, vec![Literal::Str(text.into()).into()]).wrap()]
+      },
     }
   }
 }
 
 /// Placeholder function for an eventual conversion from [io::Error] to Orchid
 /// data
-fn wrap_io_error(_e: io::Error) -> ExprInst {
-  Literal::Uint(0u64).into()
-}
+fn wrap_io_error(_e: io::Error) -> ExprInst { Literal::Uint(0u64).into() }
 
 /// Writing command (string or binary)
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]

src/systems/mod.rs

@@ -3,11 +3,11 @@ mod assertion_error;
 pub mod asynch;
 pub mod cast_exprinst;
 pub mod codegen;
+mod directfs;
 pub mod io;
 mod runtime_error;
-pub mod stl;
-mod directfs;
 pub mod scheduler;
+pub mod stl;
 
 pub use assertion_error::AssertionError;
 pub use runtime_error::RuntimeError;

src/systems/scheduler/busy.rs

@@ -1,17 +1,14 @@
 use std::any::Any;
 use std::collections::VecDeque;
 
-use crate::interpreted::ExprInst;
-
 use super::Canceller;
+use crate::interpreted::ExprInst;
 
 pub type SyncResult<T> = (T, Box<dyn Any + Send>);
 pub type SyncOperation<T> =
   Box<dyn FnOnce(T, Canceller) -> SyncResult<T> + Send>;
-pub type SyncOpResultHandler<T> = Box<
-  dyn FnOnce(T, Box<dyn Any + Send>, Canceller) -> (T, Vec<ExprInst>),
->;
-
+pub type SyncOpResultHandler<T> =
+  Box<dyn FnOnce(T, Box<dyn Any + Send>, Canceller) -> (T, Vec<ExprInst>)>;
 
 struct SyncQueueItem<T> {
   cancelled: Canceller,
@@ -89,9 +86,7 @@ impl<T> BusyState<T> {
     self.seal = Some(Box::new(recipient))
   }
 
-  pub fn is_sealed(&self) -> bool {
-    self.seal.is_some()
-  }
+  pub fn is_sealed(&self) -> bool { self.seal.is_some() }
 
   pub fn rotate<U: Send + 'static>(
     mut self,

src/systems/scheduler/canceller.rs

@@ -1,32 +1,26 @@
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Arc;
 
-use crate::atomic_inert;
+use crate::foreign::InertAtomic;
 
 /// A single-fire thread-safe boolean flag with relaxed ordering
 #[derive(Debug, Clone)]
 pub struct Canceller(Arc<AtomicBool>);
-atomic_inert!(Canceller, typestr = "a canceller");
+impl InertAtomic for Canceller {
+  fn type_str() -> &'static str { "a canceller" }
+}
 
 impl Canceller {
   /// Create a new canceller
-  pub fn new() -> Self {
-    Canceller(Arc::new(AtomicBool::new(false)))
-  }
+  pub fn new() -> Self { Canceller(Arc::new(AtomicBool::new(false))) }
 
   /// Check whether the operation has been cancelled
-  pub fn is_cancelled(&self) -> bool {
-    self.0.load(Ordering::Relaxed)
-  }
+  pub fn is_cancelled(&self) -> bool { self.0.load(Ordering::Relaxed) }
 
   /// Cancel the operation
-  pub fn cancel(&self) {
-    self.0.store(true, Ordering::Relaxed)
-  }
+  pub fn cancel(&self) { self.0.store(true, Ordering::Relaxed) }
 }
 
 impl Default for Canceller {
-  fn default() -> Self {
-    Self::new()
-  }
+  fn default() -> Self { Self::new() }
 }

src/systems/scheduler/mod.rs

@@ -2,9 +2,8 @@
 //! reference to a shared resource.
 
 mod busy;
-mod system;
 mod canceller;
-mod take_and_drop;
+mod system;
 
 pub use canceller::Canceller;
 pub use system::{SealedOrTaken, SeqScheduler, SharedHandle, SharedState};

src/systems/scheduler/system.rs

@@ -8,17 +8,20 @@ use itertools::Itertools;
 use trait_set::trait_set;
 
 use super::busy::{BusyState, NextItemReportKind};
-use super::take_and_drop::{request, TakeAndDrop, TakeCmd};
 use super::Canceller;
 use crate::facade::{IntoSystem, System};
-use crate::foreign::cps_box::CPSBox;
+use crate::foreign::cps_box::{init_cps, CPSBox};
+use crate::foreign::InertAtomic;
 use crate::interpreted::ExprInst;
 use crate::interpreter::HandlerTable;
 use crate::systems::asynch::{AsynchSystem, MessagePort};
+use crate::systems::cast_exprinst::with_atom;
 use crate::systems::stl::Boolean;
+use crate::systems::AssertionError;
+use crate::utils::ddispatch::{request, Request};
 use crate::utils::thread_pool::ThreadPool;
 use crate::utils::{take_with_output, unwrap_or, IdMap};
-use crate::{atomic_inert, define_fn, ConstTree};
+use crate::{define_fn, ConstTree};
 
 enum SharedResource<T> {
   Free(T),
@@ -45,18 +48,17 @@ pub enum SharedState {
 
 /// A shared handle for a resource of type `T` that can be used with a
 /// [SeqScheduler] to execute mutating operations one by one in worker threads.
-pub struct SharedHandle<T> {
-  state: Rc<RefCell<SharedResource<T>>>,
-}
+pub struct SharedHandle<T>(Rc<RefCell<SharedResource<T>>>);
+
 impl<T> SharedHandle<T> {
   /// Wrap a value to be accessible to a [SeqScheduler].
   pub fn wrap(t: T) -> Self {
-    Self { state: Rc::new(RefCell::new(SharedResource::Free(t))) }
+    Self(Rc::new(RefCell::new(SharedResource::Free(t))))
   }
 
   /// Check the state of the handle
   pub fn state(&self) -> SharedState {
-    match &*self.state.as_ref().borrow() {
+    match &*self.0.as_ref().borrow() {
       SharedResource::Busy(b) if b.is_sealed() => SharedState::Sealed,
       SharedResource::Busy(_) => SharedState::Busy,
       SharedResource::Free(_) => SharedState::Free,
@@ -69,32 +71,24 @@ impl<T> SharedHandle<T> {
   /// sense as eg. an optimization. You can return the value after processing
   /// via [SyncHandle::untake].
   pub fn take(&self) -> Option<T> {
-    take_with_output(
-      &mut *self.state.as_ref().borrow_mut(),
-      |state| match state {
-        SharedResource::Free(t) => (SharedResource::Taken, Some(t)),
-        _ => (state, None),
-      },
-    )
+    take_with_output(&mut *self.0.as_ref().borrow_mut(), |state| match state {
+      SharedResource::Free(t) => (SharedResource::Taken, Some(t)),
+      _ => (state, None),
+    })
   }
 
   /// Return the value to a handle that doesn't have one. The intended use case
   /// is to return values synchronously after they have been removed with
   /// [SyncHandle::untake].
   pub fn untake(&self, value: T) -> Result<(), T> {
-    take_with_output(
-      &mut *self.state.as_ref().borrow_mut(),
-      |state| match state {
-        SharedResource::Taken => (SharedResource::Free(value), Ok(())),
-        _ => (state, Err(value)),
-      },
-    )
+    take_with_output(&mut *self.0.as_ref().borrow_mut(), |state| match state {
+      SharedResource::Taken => (SharedResource::Free(value), Ok(())),
+      _ => (state, Err(value)),
+    })
   }
 }
 impl<T> Clone for SharedHandle<T> {
-  fn clone(&self) -> Self {
-    Self { state: self.state.clone() }
-  }
+  fn clone(&self) -> Self { Self(self.0.clone()) }
 }
 impl<T> Debug for SharedHandle<T> {
   fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -104,23 +98,46 @@ impl<T> Debug for SharedHandle<T> {
       .finish()
   }
 }
+impl<T: 'static> InertAtomic for SharedHandle<T> {
+  fn type_str() -> &'static str { "a SharedHandle" }
+  fn respond(&self, mut request: Request) {
+    request.serve_with(|| {
+      let this = self.clone();
+      TakeCmd(Rc::new(move |sch| {
+        let _ = sch.seal(this.clone(), |_| Vec::new());
+      }))
+    })
+  }
+}
 
-atomic_inert! {
-  SharedHandle(T),
-  typestr = "a shared handle",
-  request = |req: Box<dyn Any>, this: &SharedHandle<T>| request(this, req)
+#[derive(Clone)]
+pub struct TakeCmd(pub Rc<dyn Fn(SeqScheduler)>);
+impl Debug for TakeCmd {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    write!(f, "A command to drop a shared resource")
+  }
+}
+define_fn! {
+  pub TakeAndDrop = |x| with_atom(x, |a| match request(a.0.as_ref()) {
+    Some(t) => Ok(init_cps::<TakeCmd>(1, t)),
+    None => AssertionError::fail(x.clone(), "a SharedHandle"),
+  })
 }
 
 /// Error produced when an operation is scheduled or a seal placed on a resource
 /// which is either already sealed or taken.
 #[derive(Debug, Clone)]
 pub struct SealedOrTaken;
-atomic_inert!(
-  SealedOrTaken,
-  typestr = "a sealed-or-taken error for a shared resource"
-);
+impl InertAtomic for SealedOrTaken {
+  fn type_str() -> &'static str {
+    "a sealed-or-taken error for a shared resource"
+  }
+}
+
 define_fn! {
-  IsTakenError = |x| Ok(Boolean(SealedOrTaken::try_from(x).is_ok()).atom_cls())
+  IsTakenError = |x| {
+    Ok(Boolean(x.downcast::<SealedOrTaken>().is_ok()).atom_cls())
+  }
 }
 
 trait_set! {
@@ -184,16 +201,17 @@ impl SeqScheduler {
     handler: impl FnOnce(T, U, Canceller) -> (T, Vec<ExprInst>) + 'static,
     early_cancel: impl FnOnce(T) -> (T, Vec<ExprInst>) + 'static,
   ) -> Result<Canceller, SealedOrTaken> {
-    take_with_output(&mut *handle.state.as_ref().borrow_mut(), {
+    take_with_output(&mut *handle.0.as_ref().borrow_mut(), {
       let handle = handle.clone();
       |state| {
         match state {
           SharedResource::Taken => (SharedResource::Taken, Err(SealedOrTaken)),
-          SharedResource::Busy(mut b) =>
+          SharedResource::Busy(mut b) => {
             match b.enqueue(operation, handler, early_cancel) {
               Some(cancelled) => (SharedResource::Busy(b), Ok(cancelled)),
               None => (SharedResource::Busy(b), Err(SealedOrTaken)),
-            },
+            }
+          },
           SharedResource::Free(t) => {
             let cancelled = Canceller::new();
             drop(early_cancel); // cannot possibly be useful
@@ -212,8 +230,9 @@ impl SeqScheduler {
     handle: SharedHandle<T>,
     seal: impl FnOnce(T) -> Vec<ExprInst> + 'static,
   ) -> Result<Vec<ExprInst>, SealedOrTaken> {
-    take_with_output(&mut *handle.state.as_ref().borrow_mut(), |state| {
-      match state {
+    take_with_output(
+      &mut *handle.0.as_ref().borrow_mut(),
+      |state| match state {
         SharedResource::Busy(mut b) if !b.is_sealed() => {
           b.seal(seal);
           (SharedResource::Busy(b), Ok(Vec::new()))
@@ -221,8 +240,8 @@ impl SeqScheduler {
         SharedResource::Busy(_) => (state, Err(SealedOrTaken)),
         SharedResource::Taken => (SharedResource::Taken, Err(SealedOrTaken)),
         SharedResource::Free(t) => (SharedResource::Taken, Ok(seal(t))),
-      }
-    })
+      },
+    )
   }
 
   /// Asynchronously recursive function to schedule a new task for execution and
@@ -244,7 +263,7 @@ impl SeqScheduler {
         let (t, u): (T, U) =
           *data.downcast().expect("This is associated by ID");
         let handle2 = handle.clone();
-        take_with_output(&mut *handle.state.as_ref().borrow_mut(), |state| {
+        take_with_output(&mut *handle.0.as_ref().borrow_mut(), |state| {
           let busy = unwrap_or! { state => SharedResource::Busy;
             panic!("Handle with outstanding invocation must be busy")
           };

src/systems/scheduler/take_and_drop.rs

@@ -1,44 +0,0 @@
-use std::any::Any;
-use std::fmt::Debug;
-use std::rc::Rc;
-
-use super::{SeqScheduler, SharedHandle};
-use crate::foreign::cps_box::{init_cps, CPSBox};
-use crate::foreign::Atom;
-use crate::interpreted::Clause;
-use crate::systems::AssertionError;
-use crate::{define_fn, Primitive};
-
-pub fn request<T: 'static>(
-  handle: &SharedHandle<T>,
-  request: Box<dyn Any>,
-) -> Option<Box<dyn Any>> {
-  if request.downcast::<TakerRequest>().is_ok() {
-    let handle = handle.clone();
-    let cmd = TakeCmd(Rc::new(move |sch| {
-      let _ = sch.seal(handle.clone(), |_| Vec::new());
-    }));
-    return Some(Box::new(init_cps(1, cmd)))
-  }
-  None
-}
-
-pub struct TakerRequest;
-#[derive(Clone)]
-pub struct TakeCmd(pub Rc<dyn Fn(SeqScheduler)>);
-impl Debug for TakeCmd {
-  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-    write!(f, "A command to drop a shared resource")
-  }
-}
-define_fn! {
-  pub TakeAndDrop = |x| x.inspect(|c| match c {
-    Clause::P(Primitive::Atom(Atom(atomic))) => {
-      let t = atomic.request(Box::new(TakerRequest))
-        .ok_or_else(|| AssertionError::ext(x.clone(), "a SharedHandle"))?;
-      let data: CPSBox<TakeCmd> = *t.downcast().expect("implied by request");
-      Ok(data.atom_cls())
-    },
-    _ => AssertionError::fail(x.clone(), "an atom"),
-  })
-}

src/systems/stl/bin.rs

@@ -4,16 +4,18 @@ use std::sync::Arc;
 use itertools::Itertools;
 
 use super::Boolean;
-use crate::systems::cast_exprinst::with_uint;
+use crate::foreign::InertAtomic;
 use crate::systems::codegen::{orchid_opt, tuple};
 use crate::systems::RuntimeError;
 use crate::utils::{iter_find, unwrap_or};
-use crate::{atomic_inert, define_fn, ConstTree, Interner, Literal};
+use crate::{define_fn, ConstTree, Interner, Literal};
 
 /// A block of binary data
 #[derive(Clone, Hash, PartialEq, Eq)]
 pub struct Binary(pub Arc<Vec<u8>>);
-atomic_inert!(Binary, typestr = "a binary blob");
+impl InertAtomic for Binary {
+  fn type_str() -> &'static str { "a binary blob" }
+}
 
 impl Debug for Binary {
   fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -96,11 +98,7 @@ define_fn! {expr=x in
 
 define_fn! {expr=x in
   /// Extract a subsection of the binary data
-  pub Slice {
-    s: Binary,
-    i: u64 as with_uint(x, Ok),
-    len: u64 as with_uint(x, Ok)
-  } => {
+  pub Slice { s: Binary, i: u64, len: u64 } => {
     if i + len < s.0.len() as u64 {
       RuntimeError::fail(
         "Byte index out of bounds".to_string(),
@@ -123,10 +121,7 @@ define_fn! {expr=x in
 
 define_fn! {expr=x in
   /// Split binary data block into two smaller blocks
-  pub Split {
-    bin: Binary,
-    i: u64 as with_uint(x, Ok)
-  } => {
+  pub Split { bin: Binary, i: u64 } => {
     if bin.0.len() < *i as usize {
       RuntimeError::fail(
         "Byte index out of bounds".to_string(),
@@ -144,7 +139,7 @@ define_fn! {expr=x in
 define_fn! {
   /// Detect the number of bytes in the binary data block
   pub Size = |x| {
-    Ok(Literal::Uint(Binary::try_from(x)?.0.len() as u64).into())
+    Ok(Literal::Uint(x.downcast::<Binary>()?.0.len() as u64).into())
   }
 }
 

src/systems/stl/bool.rs

@@ -1,19 +1,20 @@
 use std::rc::Rc;
 
+use crate::foreign::InertAtomic;
 use crate::interner::Interner;
 use crate::representations::interpreted::Clause;
 use crate::systems::AssertionError;
-use crate::{atomic_inert, define_fn, ConstTree, Literal, PathSet};
+use crate::{define_fn, ConstTree, Literal, PathSet};
 
 /// Booleans exposed to Orchid
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct Boolean(pub bool);
-atomic_inert!(Boolean, typestr = "a boolean");
+impl InertAtomic for Boolean {
+  fn type_str() -> &'static str { "a boolean" }
+}
 
 impl From<bool> for Boolean {
-  fn from(value: bool) -> Self {
-    Self(value)
-  }
+  fn from(value: bool) -> Self { Self(value) }
 }
 
 define_fn! {expr=x in
@@ -36,7 +37,7 @@ define_fn! {expr=x in
 define_fn! {
   /// Takes a boolean and two branches, runs the first if the bool is true, the
   /// second if it's false.
-  IfThenElse = |x| x.try_into()
+  IfThenElse = |x| x.downcast()
     .map_err(|_| AssertionError::ext(x.clone(), "a boolean"))
     .map(|b: Boolean| if b.0 {Clause::Lambda {
       args: Some(PathSet { steps: Rc::new(vec![]), next: None }),

src/systems/stl/inspect.rs

@@ -3,7 +3,8 @@ use std::fmt::Debug;
 use crate::foreign::{Atomic, AtomicReturn};
 use crate::interpreter::Context;
 use crate::representations::interpreted::ExprInst;
-use crate::{atomic_defaults, write_fn_step, ConstTree, Interner};
+use crate::utils::ddispatch::Responder;
+use crate::{write_fn_step, ConstTree, Interner};
 
 write_fn_step! {
   /// Print and return whatever expression is in the argument without
@@ -15,8 +16,9 @@ write_fn_step! {
 struct Inspect1 {
   expr_inst: ExprInst,
 }
+impl Responder for Inspect1 {}
 impl Atomic for Inspect1 {
-  atomic_defaults!();
+  fn as_any(&self) -> &dyn std::any::Any { self }
   fn run(&self, ctx: Context) -> crate::foreign::AtomicResult {
     println!("{}", self.expr_inst);
     Ok(AtomicReturn {

src/systems/stl/num.rs

@@ -4,6 +4,7 @@ use ordered_float::NotNan;
 
 use super::ArithmeticError;
 use crate::foreign::ExternError;
+use crate::interpreted::TryFromExprInst;
 use crate::representations::interpreted::{Clause, ExprInst};
 use crate::representations::{Literal, Primitive};
 use crate::systems::cast_exprinst::with_lit;
@@ -40,14 +41,12 @@ impl Numeric {
     }
   }
 }
-
-impl TryFrom<&ExprInst> for Numeric {
-  type Error = Rc<dyn ExternError>;
-  fn try_from(value: &ExprInst) -> Result<Self, Self::Error> {
-    with_lit(value, |l| match l {
+impl TryFromExprInst for Numeric {
+  fn from_exi(exi: &ExprInst) -> Result<Self, Rc<dyn ExternError>> {
+    with_lit(exi, |l| match l {
       Literal::Uint(i) => Ok(Numeric::Uint(*i)),
       Literal::Num(n) => Ok(Numeric::Num(*n)),
-      _ => AssertionError::fail(value.clone(), "an integer or number")?,
+      _ => AssertionError::fail(exi.clone(), "an integer or number")?,
     })
   }
 }

src/systems/stl/state.rs

@@ -2,15 +2,17 @@ use std::cell::RefCell;
 use std::rc::Rc;
 
 use crate::foreign::cps_box::{const_cps, init_cps, CPSBox};
-use crate::foreign::Atomic;
+use crate::foreign::{Atomic, InertAtomic};
 use crate::interpreted::ExprInst;
 use crate::interpreter::HandlerTable;
 use crate::systems::codegen::call;
-use crate::{atomic_inert, define_fn, ConstTree, Interner};
+use crate::{define_fn, ConstTree, Interner};
 
 #[derive(Debug, Clone)]
 pub struct State(Rc<RefCell<ExprInst>>);
-atomic_inert!(State, typestr = "a state");
+impl InertAtomic for State {
+  fn type_str() -> &'static str { "a stateful container" }
+}
 
 #[derive(Debug, Clone)]
 struct NewStateCmd;
@@ -21,8 +23,8 @@ struct SetStateCmd(State);
 #[derive(Debug, Clone)]
 struct GetStateCmd(State);
 
-define_fn! { SetState = |x| Ok(init_cps(2, SetStateCmd(x.try_into()?))) }
-define_fn! { GetState = |x| Ok(init_cps(2, GetStateCmd(x.try_into()?))) }
+define_fn! { SetState = |x| Ok(init_cps(2, SetStateCmd(x.downcast()?))) }
+define_fn! { GetState = |x| Ok(init_cps(2, GetStateCmd(x.downcast()?))) }
 
 fn new_state_handler<E>(cmd: &CPSBox<NewStateCmd>) -> Result<ExprInst, E> {
   let (_, default, handler) = cmd.unpack2();

src/utils/boxed_iter.rs

@@ -6,13 +6,9 @@ use std::iter;
 /// initialized form multiple iterators of incompatible types
 pub type BoxedIter<'a, T> = Box<dyn Iterator<Item = T> + 'a>;
 /// creates a [BoxedIter] of a single element
-pub fn box_once<'a, T: 'a>(t: T) -> BoxedIter<'a, T> {
-  Box::new(iter::once(t))
-}
+pub fn box_once<'a, T: 'a>(t: T) -> BoxedIter<'a, T> { Box::new(iter::once(t)) }
 /// creates an empty [BoxedIter]
-pub fn box_empty<'a, T: 'a>() -> BoxedIter<'a, T> {
-  Box::new(iter::empty())
-}
+pub fn box_empty<'a, T: 'a>() -> BoxedIter<'a, T> { Box::new(iter::empty()) }
 
 /// Chain various iterators into a [BoxedIter]
 macro_rules! box_chain {

src/utils/ddispatch.rs

@@ -0,0 +1,29 @@
+//! A variant of [std::any::Provider]
+
+use std::any::Any;
+
+/// A request for a value of an unknown type
+pub struct Request<'a>(&'a mut dyn Any);
+impl<'a> Request<'a> {
+  pub fn can_serve<T: 'static>(&self) -> bool { self.0.is::<Option<T>>() }
+
+  pub fn serve<T: 'static>(&mut self, value: T) { self.serve_with(|| value) }
+
+  pub fn serve_with<T: 'static>(&mut self, provider: impl FnOnce() -> T) {
+    if let Some(slot) = self.0.downcast_mut() {
+      *slot = provider();
+    }
+  }
+}
+
+/// Trait for objects that can respond to type-erased commands. This trait is
+/// a dependency of `Atomic` but the implementation can be left empty.
+pub trait Responder {
+  fn respond(&self, _request: Request) {}
+}
+
+pub fn request<T: 'static>(responder: &(impl Responder + ?Sized)) -> Option<T> {
+  let mut slot = None;
+  responder.respond(Request(&mut slot));
+  slot
+}

src/utils/delete_cell.rs

@@ -3,13 +3,9 @@ use std::rc::Rc;
 
 pub struct DeleteCell<T>(pub Rc<RefCell<Option<T>>>);
 impl<T> DeleteCell<T> {
-  pub fn new(t: T) -> Self {
-    Self(Rc::new(RefCell::new(Some(t))))
-  }
+  pub fn new(t: T) -> Self { Self(Rc::new(RefCell::new(Some(t)))) }
 
-  pub fn take(&self) -> Option<T> {
-    self.0.borrow_mut().take()
-  }
+  pub fn take(&self) -> Option<T> { self.0.borrow_mut().take() }
 
   pub fn clone_out(&self) -> Option<T>
   where
@@ -19,7 +15,5 @@ impl<T> DeleteCell<T> {
   }
 }
 impl<T> Clone for DeleteCell<T> {
-  fn clone(&self) -> Self {
-    Self(self.0.clone())
-  }
+  fn clone(&self) -> Self { Self(self.0.clone()) }
 }

src/utils/id_map.rs

@@ -14,14 +14,10 @@ pub struct IdMap<T> {
 }
 impl<T> IdMap<T> {
   /// Create a new empty set
-  pub fn new() -> Self {
-    Self { next_id: 0, data: HashMap::new() }
-  }
+  pub fn new() -> Self { Self { next_id: 0, data: HashMap::new() } }
 
   /// Obtain a reference to the underlying map for iteration
-  pub fn map(&self) -> &HashMap<u64, T> {
-    &self.data
-  }
+  pub fn map(&self) -> &HashMap<u64, T> { &self.data }
 
   /// Insert an element with a new ID and return the ID
   pub fn insert(&mut self, t: T) -> u64 {
@@ -33,9 +29,7 @@ impl<T> IdMap<T> {
   }
 
   /// Obtain a reference to the element with the given ID
-  pub fn get(&self, id: u64) -> Option<&T> {
-    self.data.get(&id)
-  }
+  pub fn get(&self, id: u64) -> Option<&T> { self.data.get(&id) }
 
   /// Obtain a mutable reference to the element with the given ID
   pub fn get_mut(&mut self, id: u64) -> Option<&mut T> {
@@ -44,15 +38,11 @@ impl<T> IdMap<T> {
 
   /// Remove the element with the given ID from the set. The ID will not be
   /// reused.
-  pub fn remove(&mut self, id: u64) -> Option<T> {
-    self.data.remove(&id)
-  }
+  pub fn remove(&mut self, id: u64) -> Option<T> { self.data.remove(&id) }
 }
 
 impl<T> Default for IdMap<T> {
-  fn default() -> Self {
-    Self::new()
-  }
+  fn default() -> Self { Self::new() }
 }
 
 #[cfg(test)]

src/utils/mod.rs

@@ -1,9 +1,11 @@
 mod cache;
+pub mod ddispatch;
 mod delete_cell;
-pub mod poller;
 pub mod get_or;
+mod id_map;
 mod iter_find;
 pub mod never;
+pub mod poller;
 pub mod pure_push;
 pub mod rc_tools;
 mod replace_first;
@@ -14,7 +16,6 @@ pub mod substack;
 mod take_with_output;
 pub mod thread_pool;
 mod unwrap_or;
-mod id_map;
 
 pub use cache::Cache;
 pub use replace_first::replace_first;
@@ -22,9 +23,9 @@ pub use side::Side;
 pub use split_max_prefix::split_max_prefix;
 pub(crate) use unwrap_or::unwrap_or;
 pub mod boxed_iter;
-pub use delete_cell::DeleteCell;
 pub use boxed_iter::BoxedIter;
+pub use delete_cell::DeleteCell;
+pub use id_map::IdMap;
 pub use iter_find::iter_find;
 pub use string_from_charset::string_from_charset;
 pub use take_with_output::take_with_output;
-pub use id_map::IdMap;

src/utils/never.rs

@@ -7,9 +7,7 @@ pub enum Never {}
 pub type Always<T> = Result<T, Never>;
 
 /// Wrap value in a result with an impossible failure mode
-pub fn always<T>(t: T) -> Result<T, Never> {
-  Ok(t)
-}
+pub fn always<T>(t: T) -> Result<T, Never> { Ok(t) }
 
 /// Take success value out of a result with an impossible failure mode
 pub fn unwrap_always<T>(result: Result<T, Never>) -> T {

src/utils/poller.rs

@@ -37,9 +37,7 @@ impl<TOnce, TRec> Clone for Timer<TOnce, TRec> {
 }
 impl<TOnce, TRec> Eq for Timer<TOnce, TRec> {}
 impl<TOnce, TRec> PartialEq for Timer<TOnce, TRec> {
-  fn eq(&self, other: &Self) -> bool {
-    self.expires.eq(&other.expires)
-  }
+  fn eq(&self, other: &Self) -> bool { self.expires.eq(&other.expires) }
 }
 impl<TOnce, TRec> PartialOrd for Timer<TOnce, TRec> {
   fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {

src/utils/side.rs

@@ -31,9 +31,7 @@ impl Side {
     }
   }
   /// Shorthand for opposite
-  pub fn inv(&self) -> Self {
-    self.opposite()
-  }
+  pub fn inv(&self) -> Self { self.opposite() }
   /// take N elements from this end of a slice
   pub fn slice<'a, T>(&self, size: usize, slice: &'a [T]) -> &'a [T] {
     match self {
@@ -85,9 +83,7 @@ impl Side {
 impl Not for Side {
   type Output = Side;
 
-  fn not(self) -> Self::Output {
-    self.opposite()
-  }
+  fn not(self) -> Self::Output { self.opposite() }
 }
 
 #[cfg(test)]

src/utils/substack.rs

@@ -32,13 +32,9 @@ impl<'a, T> Substack<'a, T> {
     }
   }
   /// Construct an iterator over the listlike, very fast O(1)
-  pub fn iter(&self) -> SubstackIterator<T> {
-    SubstackIterator { curr: self }
-  }
+  pub fn iter(&self) -> SubstackIterator<T> { SubstackIterator { curr: self } }
   /// Add the item to this substack
-  pub fn push(&'a self, item: T) -> Self {
-    Self::Frame(self.new_frame(item))
-  }
+  pub fn push(&'a self, item: T) -> Self { Self::Frame(self.new_frame(item)) }
   /// Create a new frame on top of this substack
   pub fn new_frame(&'a self, item: T) -> Stackframe<'a, T> {
     Stackframe { item, prev: self, len: self.opt().map_or(1, |s| s.len + 1) }
@@ -61,9 +57,7 @@ impl<'a, T> Substack<'a, T> {
     }
   }
   /// is this the bottom of the stack
-  pub fn is_empty(&self) -> bool {
-    self.len() == 0
-  }
+  pub fn is_empty(&self) -> bool { self.len() == 0 }
 }
 
 impl<'a, T: Debug> Debug for Substack<'a, T> {
@@ -104,9 +98,7 @@ impl<'a, T> SubstackIterator<'a, T> {
 
 impl<'a, T> Copy for SubstackIterator<'a, T> {}
 impl<'a, T> Clone for SubstackIterator<'a, T> {
-  fn clone(&self) -> Self {
-    Self { curr: self.curr }
-  }
+  fn clone(&self) -> Self { Self { curr: self.curr } }
 }
 
 impl<'a, T> Iterator for SubstackIterator<'a, T> {

src/utils/thread_pool.rs

@@ -16,9 +16,7 @@ pub trait Task: Send + 'static {
 }
 
 impl<F: FnOnce() + Send + 'static> Task for F {
-  fn run(self) {
-    self()
-  }
+  fn run(self) { self() }
 }
 
 /// An async unit of work that produces some result, see [Task]. This can be
@@ -49,9 +47,7 @@ pub trait Query: Send + 'static {
 impl<F: FnOnce() -> R + Send + 'static, R: Send + 'static> Query for F {
   type Result = R;
 
-  fn run(self) -> Self::Result {
-    self()
-  }
+  fn run(self) -> Self::Result { self() }
 }
 
 /// A reporter that calls a statically known function with the result of a
@@ -61,9 +57,7 @@ pub struct QueryTask<Q: Query, F: FnOnce(Q::Result) + Send + 'static> {
   callback: F,
 }
 impl<Q: Query, F: FnOnce(Q::Result) + Send + 'static> Task for QueryTask<Q, F> {
-  fn run(self) {
-    (self.callback)(self.query.run())
-  }
+  fn run(self) { (self.callback)(self.query.run()) }
 }
 
 enum Message<T: Task> {
@@ -91,9 +85,7 @@ struct ThreadPoolData<T: Task> {
 ///
 /// struct MyTask(&'static str);
 /// impl Task for MyTask {
-///   fn run(self) {
-///     println!("{}", self.0)
-///   }
+///   fn run(self) { println!("{}", self.0) }
 /// }
 ///
 /// let pool = ThreadPool::new();
@@ -167,9 +159,7 @@ impl<T: Task> ThreadPool<T> {
 }
 
 impl<T: Task> Default for ThreadPool<T> {
-  fn default() -> Self {
-    Self::new()
-  }
+  fn default() -> Self { Self::new() }
 }
 
 impl<T: Task> Drop for ThreadPool<T> {