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

src/backend/into_crane.rs

@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 
 use crate::eval::PrimitiveType;
-use crate::ir::{Expression, Primitive, Program, Statement, Type, Value, ValueOrRef};
+use crate::ir::{Expression, Primitive, Program, Statement, TopLevel, Type, Value, ValueOrRef};
 use crate::syntax::ConstantType;
 use cranelift_codegen::entity::EntityRef;
 use cranelift_codegen::ir::{
@@ -120,12 +120,14 @@ impl<M: Module> Backend<M> {
         // this is likely to become more cumbersome, and we'll want to separate
         // these off. But for now, given the amount of tables we keep around to track
         // state, it's easier to just include them.
-        for stmt in program.statements.drain(..) {
-            match stmt {
+        for item in program.items.drain(..) {
+            match item {
+                TopLevel::Function(_, _, _) => unimplemented!(),
+
                 // Print statements are fairly easy to compile: we just lookup the
                 // output buffer, the address of the string to print, and the value
                 // of whatever variable we're printing. Then we just call print.
-                Statement::Print(ann, t, var) => {
+                TopLevel::Statement(Statement::Print(ann, t, var)) => {
                     // Get the output buffer (or null) from our general compilation context.
                     let buffer_ptr = self.output_buffer_ptr();
                     let buffer_ptr = builder.ins().iconst(types::I64, buffer_ptr as i64);
@@ -163,7 +165,7 @@ impl<M: Module> Backend<M> {
                 }
 
                 // Variable binding is a little more con
-                Statement::Binding(_, var_name, _, value) => {
+                TopLevel::Statement(Statement::Binding(_, var_name, _, value)) => {
                     // Kick off to the `Expression` implementation to see what value we're going
                     // to bind to this variable.
                     let (val, etype) =