From 53d64addb99d1bfa38d196e7383b1350ddb957be Mon Sep 17 00:00:00 2001
From: Andrew Morris <voltrevo@gmail.com>
Date: Wed, 8 Mar 2023 09:40:32 +1100
Subject: [PATCH] Add Lazy to asm.rs

---
 valuescript_compiler/src/asm.rs       | 28 +++++++++++++++++++++++
 valuescript_compiler/src/assembler.rs | 33 ++++++++++++++++++++++++++-
 2 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/valuescript_compiler/src/asm.rs b/valuescript_compiler/src/asm.rs
index 59bca89..b2996a9 100644
--- a/valuescript_compiler/src/asm.rs
+++ b/valuescript_compiler/src/asm.rs
@@ -64,6 +64,7 @@ pub enum DefinitionContent {
   Function(Function),
   Class(Class),
   Value(Value),
+  Lazy(Lazy),
 }
 
 impl std::fmt::Display for DefinitionContent {
@@ -78,6 +79,9 @@ impl std::fmt::Display for DefinitionContent {
       DefinitionContent::Value(value) => {
         write!(f, "{}", value)
       }
+      DefinitionContent::Lazy(lazy) => {
+        write!(f, "{}", lazy)
+      }
     }
   }
 }
@@ -499,6 +503,30 @@ impl std::fmt::Display for Value {
   }
 }
 
+#[derive(Debug)]
+pub struct Lazy {
+  pub body: Vec<InstructionOrLabel>,
+}
+
+impl std::fmt::Display for Lazy {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    write!(f, "lazy {{\n")?;
+
+    for instruction_or_label in &self.body {
+      match instruction_or_label {
+        InstructionOrLabel::Instruction(instruction) => {
+          write!(f, "  {}\n", instruction)?;
+        }
+        InstructionOrLabel::Label(label) => {
+          write!(f, "{}\n", label)?;
+        }
+      }
+    }
+
+    write!(f, "}}")
+  }
+}
+
 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
 pub struct Builtin {
   pub name: String,
diff --git a/valuescript_compiler/src/assembler.rs b/valuescript_compiler/src/assembler.rs
index 48a63e3..ea3dcd6 100644
--- a/valuescript_compiler/src/assembler.rs
+++ b/valuescript_compiler/src/assembler.rs
@@ -5,7 +5,7 @@ use std::{
 
 use crate::asm::{
   Array, Builtin, Class, Definition, DefinitionContent, Function, Instruction, InstructionOrLabel,
-  Label, LabelRef, Module, Object, Pointer, Register, Value,
+  Label, LabelRef, Lazy, Module, Object, Pointer, Register, Value,
 };
 
 pub fn assemble(module: &Module) -> Rc<Vec<u8>> {
@@ -58,6 +58,9 @@ impl Assembler {
       DefinitionContent::Value(value) => {
         self.value(value);
       }
+      DefinitionContent::Lazy(lazy) => {
+        self.lazy(lazy);
+      }
     }
   }
 
@@ -105,6 +108,33 @@ impl Assembler {
     self.fn_data.labels_map.resolve(&mut self.output);
   }
 
+  fn lazy(&mut self, lazy: &Lazy) {
+    self.output.push(ValueType::Lazy as u8);
+
+    self.fn_data = Default::default();
+    self.fn_data.register_count_pos = self.output.len();
+    self.output.push(0xff); // Placeholder for register count
+
+    for instruction_or_label in &lazy.body {
+      match instruction_or_label {
+        InstructionOrLabel::Instruction(instruction) => {
+          self.instruction(instruction);
+        }
+        InstructionOrLabel::Label(label) => {
+          self.label(label);
+        }
+      }
+    }
+
+    self.output.push(Instruction::End.byte());
+
+    // TODO: Handle >255 registers
+    // +3: return, this, ignore
+    self.output[self.fn_data.register_count_pos] = (self.fn_data.register_map.len() + 3) as u8;
+
+    self.fn_data.labels_map.resolve(&mut self.output);
+  }
+
   fn class(&mut self, class: &Class) {
     self.output.push(ValueType::Class as u8);
     self.value(&class.constructor);
@@ -344,6 +374,7 @@ enum ValueType {
   // External = 0x0f,
   Builtin = 0x10,
   Class = 0x11,
+  Lazy = 0x12,
 }
 
 #[derive(Hash, PartialEq, Eq, Clone)]