Add varargs

examples/test.lua

@@ -1,6 +1,7 @@
 
 function f(x, ...)
-    return x + 5, ...
+    local b, c = ...
+    return x + 5, b, c
 end
 
 print(123, f(10, 11, 12))

src/compile.rs

@@ -5,13 +5,13 @@ use crate::{
         AccessModifier, BinaryOperator, Block, Expression, IdentOrEllipsis, Literal, Statement,
         UnaryOperator,
     },
-    vm::{Constant, Instruction, LuaBool, LuaInteger},
+    vm::{Constant, Instruction, LuaBool, LuaInteger, Prototype},
 };
 
 #[derive(Clone, Debug)]
 pub struct State {
     pub constants: Vec<Constant>,
-    pub prototypes: Vec<Vec<Instruction>>,
+    pub prototypes: Vec<Prototype>,
 }
 
 impl State {
@@ -178,11 +178,19 @@ impl Statement {
 
                 match access_modifier {
                     Some(AccessModifier::Local) => {
+                        let mut vararg_applied = false;
                         for (i, (name, indexes)) in names.iter().enumerate() {
-                            instructions.push(Instruction::Move(
-                                *new_registers.get(i).unwrap(),
-                                expr_regs.get(i).cloned().unwrap(),
-                            ));
+                            if let Some(expr_reg) = expr_regs.get(i) {
+                                instructions.push(Instruction::Move(
+                                    *new_registers.get(i).unwrap(),
+                                    *expr_reg,
+                                ));
+                            } else if !vararg_applied {
+                                instructions.push(Instruction::MoveRetValues(
+                                    *new_registers.get(i).unwrap(),
+                                ));
+                                vararg_applied = true;
+                            }
                             if indexes.len() > 0 {
                                 todo!()
                             }
@@ -559,7 +567,14 @@ impl Expression {
                 }
 
                 let instructions = block.compile(state, &mut inner_scope);
-                state.prototypes.push(instructions);
+                state.prototypes.push(Prototype {
+                    instructions,
+                    parameters: if inner_scope.is_vararg {
+                        params.len() - 1
+                    } else {
+                        params.len()
+                    },
+                });
 
                 let mut instructions = Vec::new();
                 instructions.push(Instruction::Close(scope.register_counter.0));

src/lib.rs

@@ -70,7 +70,10 @@ impl Debug for CompilationUnit {
 
 impl CompilationUnit {
     pub fn with_virtual_machine<'a>(&self, vm: &'a mut VirtualMachine) -> ExecutionUnit<'a> {
-        let chunk_id = vm.new_prototype(self.instructions.clone());
+        let chunk_id = vm.new_prototype(vm::Prototype {
+            instructions: self.instructions.clone(),
+            parameters: 0,
+        });
         for prototype in &self.state.prototypes {
             vm.new_prototype(prototype.clone());
         }

src/vm.rs

@@ -512,16 +512,22 @@ impl<T: RustFunction + 'static> From<T> for Value {
     }
 }
 
+#[derive(Debug, Clone, Default)]
+pub struct Prototype {
+    pub instructions: Vec<Instruction>,
+    pub parameters: usize,
+}
+
 #[derive(Debug, Clone, Default)]
 pub struct VirtualMachine {
     pub(super) environment: Rc<RefCell<Environment>>,
     pub(super) constants: Vec<Constant>,
-    pub(super) prototypes: HashMap<u32, Vec<Instruction>>,
+    pub(super) prototypes: HashMap<u32, Prototype>,
     pub(super) proto_counter: u32,
 }
 
 impl VirtualMachine {
-    pub fn new_prototype(&mut self, instructions: Vec<Instruction>) -> u32 {
+    pub fn new_prototype(&mut self, instructions: Prototype) -> u32 {
         let proto_id = self.proto_counter;
         self.proto_counter += 1;
         self.prototypes.insert(proto_id, instructions);
@@ -656,7 +662,10 @@ impl ClosureRunner {
     pub fn execute(&mut self, unit: &CompilationUnit) -> ClosureRunner {
         let mut vm = self.closure.vm.clone();
         vm.constants = unit.constants.clone();
-        let proto_id = vm.new_prototype(unit.instructions.clone());
+        let proto_id = vm.new_prototype(Prototype {
+            instructions: unit.instructions.clone(),
+            parameters: 0,
+        });
         for prototype in &unit.state.prototypes {
             vm.new_prototype(prototype.clone());
         }
@@ -701,7 +710,7 @@ impl ClosureRunner {
             }
         }
 
-        let instructions = self
+        let prototype = self
             .closure
             .vm
             .prototypes
@@ -710,7 +719,7 @@ impl ClosureRunner {
             .clone();
         let constants = self.closure.vm.constants.clone();
 
-        if let Some(instr) = instructions.get(self.program_counter) {
+        if let Some(instr) = prototype.instructions.get(self.program_counter) {
             match instr {
                 Instruction::Move(a, b) => {
                     let b = self.get_stack(*b);
@@ -1090,9 +1099,16 @@ impl ClosureRunner {
                 }
                 Instruction::Vararg(reg) => {
                     self.function_register = reg - 1;
-                    self.top = self.function_register + self.parameters.len() as u16;
+                    self.top = self.function_register + self.parameters.len() as u16
+                        - prototype.parameters as u16;
 
-                    for (i, param) in self.parameters.clone().iter().enumerate() {
+                    for (i, param) in self
+                        .parameters
+                        .clone()
+                        .iter()
+                        .skip(prototype.parameters)
+                        .enumerate()
+                    {
                         self.set_stack(*reg + i as u16, StackValue::Value(param.clone()));
                     }
                 }