[fine] The VM lives! We can test it a little!

fine/src/compiler.rs

@@ -123,6 +123,14 @@ struct Compiler<'a> {
     // TODO: generic functions will actually be keyed by treeref and concrete
     //       types
     function_bindings: HashMap<TreeRef, usize>,
+
+    // We need to hold a space in the function array while we're compiling
+    // the function, but the Module functions are not Option<>. Here we just
+    // make a space that *is* Option<> so that we have a place to hold things
+    // while we compile. This will get spilled into module.functions at the
+    // end.
+    temp_functions: Vec<Option<Rc<Function>>>,
+
     module: Module,
     function: Function,
 }
@@ -211,6 +219,7 @@ pub fn compile(semantics: &Semantics) -> Rc<Module> {
         semantics,
         syntax: semantics.tree(),
         function_bindings: HashMap::new(),
+        temp_functions: Vec::new(),
         module: Module::new(),
         function: Function::new("<< module >>", 0),
     };
@@ -220,6 +229,11 @@ pub fn compile(semantics: &Semantics) -> Rc<Module> {
     }
 
     let mut module = compiler.module;
+
+    for f in compiler.temp_functions {
+        module.functions.push(f.unwrap());
+    }
+
     let index = module.functions.len();
     module.functions.push(Rc::new(compiler.function));
     module.init = index;
@@ -240,6 +254,7 @@ fn file(c: &mut Compiler, t: TreeRef) {
         }
         compile_statement(c, *children.last().unwrap(), true);
     }
+    c.push(Instruction::Return);
 }
 
 type CR = Option<()>;
@@ -568,15 +583,22 @@ fn compile_function_declaration(c: &mut Compiler, t: TreeRef, tree: &Tree, gen_v
         let param_list = tree.child_tree_of_kind(c.syntax, TreeKind::ParamList)?;
         let param_count = param_list.children.len() - 2;
 
+        let function_index = c.temp_functions.len();
+        c.temp_functions.push(None);
+        c.function_bindings.insert(t, function_index);
+
+        // Now compile the function.
         let mut prev = Function::new(name.as_str(), param_count);
         std::mem::swap(&mut c.function, &mut prev);
 
-        c.function_bindings.insert(t, c.module.functions.len());
-
         compile_expression(c, block);
+        c.push(Instruction::Return);
 
         std::mem::swap(&mut c.function, &mut prev);
-        c.module.functions.push(Rc::new(prev));
+        c.temp_functions[function_index] = Some(Rc::new(prev));
+        c.module
+            .exports
+            .insert(name.to_string(), Export::Function(function_index));
     }
 
     if gen_value {

fine/src/vm.rs

@@ -1,6 +1,6 @@
 use std::rc::Rc;
 
-use crate::compiler::{Function, Instruction, Module};
+use crate::compiler::{Export, Function, Instruction, Module};
 use crate::semantics::Type;
 use thiserror::Error;
 
@@ -175,6 +175,13 @@ impl Context {
         Context { module, globals }
     }
 
+    pub fn init(&mut self) -> std::result::Result<(), VMError> {
+        let init_index = self.module.init;
+        let init_fn = self.module.functions[init_index].clone();
+        eval(self, init_fn, vec![])?;
+        Ok(())
+    }
+
     fn get_global(&self, i: usize) -> Result<StackValue> {
         self.globals
             .get(i)
@@ -321,8 +328,10 @@ fn eval_one(
         Instruction::Return => match stack.pop() {
             Some(mut frame) => {
                 // The return value is at the top of the stack already.
+                let retval = f.pop_value()?;
                 std::mem::swap(&mut frame, f);
                 *index = f.pc;
+                f.push_value(retval);
             }
             None => return Ok(Flow::Break),
         },
@@ -343,6 +352,18 @@ pub fn eval(
     loop {
         let instructions = f.func.instructions();
         let instruction = instructions[index];
+
+        // {
+        //     eprint!("{index}: {instruction:?}  [");
+        //     for val in f.stack.iter().rev().take(3) {
+        //         eprint!("{val:?} ");
+        //     }
+        //     if f.stack.len() > 3 {
+        //         eprint!("...");
+        //     }
+        //     eprintln!("]");
+        // }
+
         index += 1;
 
         match eval_one(instruction, &mut index, c, &mut f, &mut stack) {
@@ -369,3 +390,19 @@ pub fn eval(
         };
     }
 }
+
+pub fn eval_export_fn(
+    c: &mut Context,
+    name: &str,
+    args: &[StackValue],
+) -> std::result::Result<StackValue, VMError> {
+    let export = match c.module.exports.get(name) {
+        Some(Export::Function(id)) => id,
+        Some(_) => todo!(),
+        None => todo!(),
+    };
+
+    let function = c.module.functions[*export].clone();
+    let args = args.iter().map(|a| a.clone()).collect();
+    eval(c, function, args)
+}