Variable lookup works

Note this introduces a panic - if the AST node inserted into the
environment is not reduced, it throws an error when trying to look it up

src/evaluate.rs

@@ -3,7 +3,7 @@ use std::collections::HashMap;
 use parser::AST;
 use parser::AST::*;
 
-pub struct Environment(pub HashMap<String, Box<AST>>);
+pub struct Environment(pub HashMap<String, AST>);
 type EvalResult = (AST, Environment);
 
 impl Environment {
@@ -11,17 +11,28 @@ impl Environment {
         Environment(HashMap::new())
     }
 
-    fn add_binding(&mut self, name: String, binding: Box<AST>) {
+    fn add_binding(&mut self, name: String, binding: AST) {
         match *self {
             Environment(ref mut hash_map) => hash_map.insert(name, binding)
         };
     }
 
-    fn lookup_binding(&mut self, name: &String) -> Option<&Box<AST>> {
+    fn lookup_binding(&mut self, name: &String) -> Option<&AST> {
         match *self {
             Environment(ref mut hash_map) => hash_map.get(name)
         }
     }
+
+    fn display(&self) {
+        match *self {
+            Environment(ref hash_map) =>
+                for (var, binding) in hash_map {
+                    println!("{} : {:?}", var, binding);
+                }
+        }
+
+        println!("----");
+    }
 }
 
 pub fn evaluate(ast: AST, env: Environment) -> String {
@@ -42,28 +53,38 @@ fn reduce(evr: EvalResult) -> EvalResult {
 
     match ast {
         Name(name) => {
-            match env.lookup_binding(&name) {
-                Some(_) => {
-                    (Null, env)
+            let result = match env.lookup_binding(&name) {
+                Some(binding) => match binding {
+                    &DoNothing => DoNothing,
+                    &Number(n) => Number(n),
+                    &LangString(ref s) => LangString(s.clone()),
+                    &Null => Null,
+                    _ => panic!("Unreduced ast node for name: {:?}", name)
                 },
-                None => (Null, env)
-            }
+                None => Null
+            };
+
+            (result, env)
         },
 
         Statements(stmts) => {
             let mut reduced_ast = DoNothing;
             let mut reduced_env = env;
             for stmt in stmts.into_iter() {
-                let (a, b) = reduce((stmt, reduced_env));
-                reduced_ast = a;
-                reduced_env = b;
+                let (new_ast, new_env) = reduce((stmt, reduced_env));
+                reduced_env = new_env;
+                reduced_ast = new_ast;
+
             }
             (reduced_ast, reduced_env)
         },
 
         Binding(name, binding) => {
-            env.add_binding(name, binding);
-            (DoNothing, env)
+            let unboxed_binding = *binding;
+            let (evaluated_binding, mut evaluated_env) = reduce((unboxed_binding, env));
+
+            evaluated_env.add_binding(name, evaluated_binding);
+            (DoNothing, evaluated_env)
         },
 
         other_ast => (other_ast, env)