Backup commit

My backspace key started ghosting. Nothing works atm.

src/interpreter/context.rs

@@ -1,32 +1,38 @@
 use hashbrown::HashMap;
 
-use crate::interner::Interner;
-use crate::representations::interpreted::ExprInst;
-use crate::Sym;
+use super::nort::Expr;
+use crate::name::Sym;
 
 /// All the data associated with an interpreter run
 #[derive(Clone)]
-pub struct Context<'a> {
+pub struct RunContext<'a> {
   /// Table used to resolve constants
-  pub symbols: &'a HashMap<Sym, ExprInst>,
-  /// The interner used for strings internally, so external functions can
-  /// deduce referenced constant names on the fly
-  pub interner: &'a Interner,
+  pub symbols: &'a HashMap<Sym, Expr>,
   /// The number of reduction steps the interpreter can take before returning
   pub gas: Option<usize>,
 }
+impl<'a> RunContext<'a> {
+  /// Consume some gas if it is being counted
+  pub fn use_gas(&mut self, amount: usize) {
+    if let Some(g) = self.gas.as_mut() {
+      *g = g.saturating_sub(amount)
+    }
+  }
+  /// Gas is being counted and there is none left
+  pub fn no_gas(&self) -> bool { self.gas == Some(0) }
+}
 
 /// All the data produced by an interpreter run
 #[derive(Clone)]
-pub struct Return {
+pub struct Halt {
   /// The new expression tree
-  pub state: ExprInst,
+  pub state: Expr,
   /// Leftover [Context::gas] if counted
   pub gas: Option<usize>,
   /// If true, the next run would not modify the expression
   pub inert: bool,
 }
-impl Return {
+impl Halt {
   /// Check if gas has run out. Returns false if gas is not being used
   pub fn preempted(&self) -> bool { self.gas.map_or(false, |g| g == 0) }
   /// Returns a general report of the return