September-october commit

- manual parser
- stl refinements
- all language constructs are now Send

src/foreign/extern_fn.rs

@@ -3,13 +3,12 @@ use std::fmt::{Debug, Display};
 use std::hash::Hash;
 use std::rc::Rc;
 
-use dyn_clone::DynClone;
+use dyn_clone::{DynClone, clone_box};
 
 use super::XfnResult;
 use crate::interpreted::ExprInst;
 use crate::interpreter::Context;
 use crate::representations::interpreted::Clause;
-use crate::Primitive;
 
 /// Errors produced by external code
 pub trait ExternError: Display {
@@ -34,7 +33,7 @@ impl Error for dyn ExternError {}
 /// Represents an externally defined function from the perspective of
 /// the executor. Since Orchid lacks basic numerical operations,
 /// these are also external functions.
-pub trait ExternFn: DynClone {
+pub trait ExternFn: DynClone + Send {
   /// Display name of the function
   #[must_use]
   fn name(&self) -> &str;
@@ -50,7 +49,7 @@ pub trait ExternFn: DynClone {
   where
     Self: Sized + 'static,
   {
-    Clause::P(Primitive::ExternFn(Box::new(self)))
+    Clause::ExternFn(ExFn(Box::new(self)))
   }
 }
 
@@ -68,3 +67,21 @@ impl Debug for dyn ExternFn {
     write!(f, "##EXTERN[{}]##", self.name())
   }
 }
+
+/// Represents a black box function that can be applied to a [Clause] to produce
+/// a new [Clause], typically an [Atom] representing external work, a new [ExFn]
+/// to take additional arguments, or an Orchid tree to return control to the
+/// interpreter
+#[derive(Debug)]
+pub struct ExFn(pub Box<dyn ExternFn + 'static>);
+impl ExFn {
+  /// Combine the function with an argument to produce a new clause
+  pub fn apply(self, arg: ExprInst, ctx: Context) -> XfnResult<Clause> {
+    self.0.apply(arg, ctx)
+  }
+}
+impl Clone for ExFn {
+  fn clone(&self) -> Self {
+    Self(clone_box(self.0.as_ref()))
+  }
+}