Wire functions through everything, with some unimplemented, and add a basic scoped map.

src/syntax/eval.rs

@@ -1,7 +1,7 @@
 use internment::ArcIntern;
 
 use crate::eval::{EvalEnvironment, EvalError, PrimitiveType, Value};
-use crate::syntax::{ConstantType, Expression, Program, Statement};
+use crate::syntax::{ConstantType, Expression, Program, Statement, TopLevel};
 use std::str::FromStr;
 
 impl Program {
@@ -19,16 +19,19 @@ impl Program {
         let mut env = EvalEnvironment::empty();
         let mut stdout = String::new();
 
-        for stmt in self.statements.iter() {
-            // at this point, evaluation is pretty simple. just walk through each
-            // statement, in order, and record printouts as we come to them.
+        for stmt in self.items.iter() {
             match stmt {
-                Statement::Binding(_, name, value) => {
+                TopLevel::Function(_name, _arg_names, _body) => {
+                    unimplemented!()
+                }
+                // at this point, evaluation is pretty simple. just walk through each
+                // statement, in order, and record printouts as we come to them.
+                TopLevel::Statement(Statement::Binding(_, name, value)) => {
                     let actual_value = value.eval(&env)?;
                     env = env.extend(name.clone().intern(), actual_value);
                 }
 
-                Statement::Print(_, name) => {
+                TopLevel::Statement(Statement::Print(_, name)) => {
                     let value = env.lookup(name.clone().intern())?;
                     let line = format!("{} = {}\n", name, value);
                     stdout.push_str(&line);