streamline code generation with iterators and traits

src/l0/ast.rs

@@ -1,3 +1,4 @@
+use std::cell::{Cell};
 use std::vec::{Vec};
 
 pub type Var = String;
@@ -12,24 +13,39 @@ pub enum TopLevel {
 
 #[derive(Debug)]
 pub enum Term {
-    Atom(Atom),
-    Clause(Atom, Vec<Box<Term>>),
-    Var(Var)
+    Atom(Cell<usize>, Atom),
+    Clause(Cell<usize>, Atom, Vec<Box<Term>>),
+    Var(Cell<usize>, Var)
 }
 
-pub enum MachineInstruction {
+pub enum FactInstruction {
     GetStructure(Atom, usize, usize),
-    PutStructure(Atom, usize, usize),
-    SetVariable(usize),
-    SetValue(usize),
     UnifyVariable(usize),
     UnifyValue(usize)
 }
 
-pub type Program = Vec<MachineInstruction>;
+pub enum QueryInstruction {    
+    PutStructure(Atom, usize, usize),
+    SetVariable(usize),
+    SetValue(usize),    
+}
+
+pub type CompiledFact = Vec<FactInstruction>;
+
+pub type CompiledQuery = Vec<QueryInstruction>;
 
 #[derive(Clone, Copy, PartialEq)]
 pub enum Addr {
     HeapCell(usize),
     RegNum(usize)
 }
+
+impl Term {
+    pub fn set_cell(&self, cell_num: usize) {
+        match self {
+            &Term::Atom(ref cell, _) => cell.set(cell_num),
+            &Term::Clause(ref cell, _, _) => cell.set(cell_num),
+            &Term::Var(ref cell, _) => cell.set(cell_num)
+        };
+    }
+}