From 50a6779bd437b7e96b994d5d96727f8b0ef350ad Mon Sep 17 00:00:00 2001
From: Empa <emanuel@empa.xyz>
Date: Wed, 17 Jan 2024 23:25:37 +0100
Subject: [PATCH] Prepare for native functions in bytecode

---
 crates/saft-ast-to-ir/src/lib.rs     | 20 ++++++++++----------
 crates/saft-bytecode/src/compiler.rs |  5 +++--
 crates/saft-bytecode/src/item.rs     |  6 +++++-
 crates/saft-ir/src/lib.rs            |  7 ++++---
 crates/saft/src/main.rs              |  9 +++++++--
 5 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/crates/saft-ast-to-ir/src/lib.rs b/crates/saft-ast-to-ir/src/lib.rs
index 85ef67e..1cc48b7 100644
--- a/crates/saft-ast-to-ir/src/lib.rs
+++ b/crates/saft-ast-to-ir/src/lib.rs
@@ -51,19 +51,19 @@ impl Error {
     }
 }
 
-enum LowererItem {
-    Ir_(Spanned<ir::Item>),
+enum LowererItem<N> {
+    Ir_(Spanned<ir::Item<N>>),
     Unlowered,
 }
 
-pub struct Lowerer {
-    items: Vec<LowererItem>,
+pub struct Lowerer<N> {
+    items: Vec<LowererItem<N>>,
     scopes: Vec<HashMap<String, ir::Ref>>,
     scope_base: usize,
     var_counter: usize,
 }
 
-impl Lowerer {
+impl<N> Lowerer<N> {
     #[allow(clippy::new_without_default)]
     pub fn new() -> Self {
         Self {
@@ -110,7 +110,7 @@ impl Lowerer {
         }
     }
 
-    fn resolve_item(&mut self, item: &Spanned<&ast::Item>) -> Result<Spanned<ir::Item>, Error> {
+    fn resolve_item(&mut self, item: &Spanned<&ast::Item>) -> Result<Spanned<ir::Item<N>>, Error> {
         let Spanned { s, v: item } = item;
 
         Ok(s.spanned(match item {
@@ -132,7 +132,7 @@ impl Lowerer {
         })
     }
 
-    pub fn lower_module(mut self, module: &ast::Module) -> Result<ir::Module, Error> {
+    pub fn lower_module(mut self, module: &ast::Module) -> Result<ir::Module<N>, Error> {
         self.resolve_module_items(module)?;
 
         let stmts = module
@@ -207,8 +207,8 @@ impl Lowerer {
     }
 
     fn lower_expr(&mut self, expr: &Spanned<ast::Expr>) -> Result<Spanned<ir::Expr>, Error> {
-        fn binary(
-            lowerer: &mut Lowerer,
+        fn binary<N>(
+            lowerer: &mut Lowerer<N>,
             lhs: &Spanned<ast::Expr>,
             rhs: &Spanned<ast::Expr>,
             op: ir::BinaryOp,
@@ -418,7 +418,7 @@ impl Lowerer {
         ref_
     }
 
-    fn replace_item(&mut self, ref_: ir::ItemRef, item: Spanned<ir::Item>) {
+    fn replace_item(&mut self, ref_: ir::ItemRef, item: Spanned<ir::Item<N>>) {
         self.items[ref_.0] = LowererItem::Ir_(item);
     }
 
diff --git a/crates/saft-bytecode/src/compiler.rs b/crates/saft-bytecode/src/compiler.rs
index 60e927b..dd30e2c 100644
--- a/crates/saft-bytecode/src/compiler.rs
+++ b/crates/saft-bytecode/src/compiler.rs
@@ -4,7 +4,7 @@ use codespan_reporting::diagnostic::{Diagnostic, Label};
 use saft_common::span::{Span, Spanned};
 use saft_ir as ir;
 
-use crate::{chunk::Chunk, item::Item, op::Op, value::SaftFunction};
+use crate::{chunk::Chunk, item::{Item, NativeFunction}, op::Op, value::SaftFunction};
 
 pub enum Error {
     Exotic {
@@ -79,7 +79,7 @@ impl Compiler {
         }
     }
 
-    pub fn compile_module(&mut self, module: &ir::Module) -> Result<(Chunk, Vec<Item>), Error> {
+    pub fn compile_module(&mut self, module: &ir::Module<NativeFunction>) -> Result<(Chunk, Vec<Item>), Error> {
         let mut chunk = Chunk::new();
 
         let mut items = module
@@ -90,6 +90,7 @@ impl Compiler {
                     ir::Item::Function(function) => {
                         Item::SaftFunction(self.compile_fn(item.s.spanned(function))?)
                     }
+                    ir::Item::NativeFunction(_) => todo!(),
                 })
             })
             .try_collect::<Vec<_>>()?;
diff --git a/crates/saft-bytecode/src/item.rs b/crates/saft-bytecode/src/item.rs
index 55a5da4..7185c96 100644
--- a/crates/saft-bytecode/src/item.rs
+++ b/crates/saft-bytecode/src/item.rs
@@ -1,6 +1,10 @@
-use crate::value::SaftFunction;
+use crate::{value::SaftFunction, vm};
 
 #[derive(Clone, Debug)]
 pub enum Item {
     SaftFunction(SaftFunction),
 }
+
+pub struct NativeFunction {
+    f: fn(&mut vm::Vm) -> Result<(), vm::Error>,
+}
diff --git a/crates/saft-ir/src/lib.rs b/crates/saft-ir/src/lib.rs
index 41788c2..90b4e3e 100644
--- a/crates/saft-ir/src/lib.rs
+++ b/crates/saft-ir/src/lib.rs
@@ -14,14 +14,15 @@ pub struct ItemRef(pub usize);
 pub struct VarRef(pub usize);
 
 #[derive(Debug)]
-pub struct Module {
-    pub items: Vec<Spanned<Item>>,
+pub struct Module<NativeFunction> {
+    pub items: Vec<Spanned<Item<NativeFunction>>>,
     pub stmts: Vec<Spanned<Stmt>>,
 }
 
 #[derive(Debug)]
-pub enum Item {
+pub enum Item<NativeFunction> {
     Function(Function),
+    NativeFunction(NativeFunction),
 }
 
 #[derive(Debug)]
diff --git a/crates/saft/src/main.rs b/crates/saft/src/main.rs
index 2db99d8..f3e4022 100644
--- a/crates/saft/src/main.rs
+++ b/crates/saft/src/main.rs
@@ -69,7 +69,12 @@ impl Saft {
         }
     }
 
-    fn try_lower(&mut self, fname: &str, s: &str, module: &ast::Module) -> Option<ir::Module> {
+    fn try_lower(
+        &mut self,
+        fname: &str,
+        s: &str,
+        module: &ast::Module,
+    ) -> Option<ir::Module<bytecode::item::NativeFunction>> {
         let mut files = SimpleFiles::new();
         let id = files.add(fname, s);
 
@@ -92,7 +97,7 @@ impl Saft {
         &mut self,
         fname: &str,
         s: &str,
-        module: &ir::Module,
+        module: &ir::Module<bytecode::item::NativeFunction>,
     ) -> Option<(bytecode::chunk::Chunk, Vec<bytecode::item::Item>)> {
         let mut files = SimpleFiles::new();
         let id = files.add(fname, s);