Functions returning tuples somewhat working, but they clobber the popped ra

rust_compiler/libs/compiler/src/test/mod.rs

@@ -47,3 +47,4 @@ mod logic_expression;
 mod loops;
 mod math_syscall;
 mod syscall;
+mod tuple_literals;

rust_compiler/libs/compiler/src/test/tuple_literals.rs

@@ -0,0 +1,317 @@
+#[cfg(test)]
+mod test {
+    use indoc::indoc;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn test_tuple_literal_declaration() -> anyhow::Result<()> {
+        let compiled = compile!(
+            debug
+            r#"
+            let (x, y) = (1, 2);
+            "#
+        );
+
+        assert_eq!(
+            compiled,
+            indoc! {
+                "
+                j main
+                main:
+                move r8 1
+                move r9 2
+                "
+            }
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_tuple_literal_declaration_with_underscore() -> anyhow::Result<()> {
+        let compiled = compile!(
+            debug
+            r#"
+            let (x, _) = (1, 2);
+            "#
+        );
+
+        assert_eq!(
+            compiled,
+            indoc! {
+                "
+                j main
+                main:
+                move r8 1
+                "
+            }
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_tuple_literal_assignment() -> anyhow::Result<()> {
+        let compiled = compile!(
+            debug
+            r#"
+            let x = 0;
+            let y = 0;
+            (x, y) = (5, 10);
+            "#
+        );
+
+        assert_eq!(
+            compiled,
+            indoc! {
+                "
+                j main
+                main:
+                move r8 0
+                move r9 0
+                move r8 5
+                move r9 10
+                "
+            }
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_tuple_literal_with_variables() -> anyhow::Result<()> {
+        let compiled = compile!(
+            debug
+            r#"
+            let a = 42;
+            let b = 99;
+            let (x, y) = (a, b);
+            "#
+        );
+
+        assert_eq!(
+            compiled,
+            indoc! {
+                "
+                j main
+                main:
+                move r8 42
+                move r9 99
+                move r10 r8
+                move r11 r9
+                "
+            }
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_tuple_literal_three_elements() -> anyhow::Result<()> {
+        let compiled = compile!(
+            debug
+            r#"
+            let (x, y, z) = (1, 2, 3);
+            "#
+        );
+
+        assert_eq!(
+            compiled,
+            indoc! {
+                "
+                j main
+                main:
+                move r8 1
+                move r9 2
+                move r10 3
+                "
+            }
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_tuple_literal_assignment_with_underscore() -> anyhow::Result<()> {
+        let compiled = compile!(
+            debug
+            r#"
+            let i = 0;
+            let x = 123;
+            (i, _) = (456, 789);
+            "#
+        );
+
+        assert_eq!(
+            compiled,
+            indoc! {
+                "
+                j main
+                main:
+                move r8 0
+                move r9 123
+                move r8 456
+                "
+            }
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_tuple_return_simple() -> anyhow::Result<()> {
+        let compiled = compile!(
+            debug
+            r#"
+            fn getPair() {
+                return (10, 20);
+            };
+            let (x, y) = getPair();
+            "#
+        );
+
+        assert_eq!(
+            compiled,
+            indoc! {
+                "
+                j main
+                getPair:
+                push ra
+                push 10
+                push 20
+                move r15 1
+                j __internal_L1
+                __internal_L1:
+                pop ra
+                j ra
+                main:
+                jal getPair
+                pop r9
+                pop r8
+                "
+            }
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_tuple_return_with_underscore() -> anyhow::Result<()> {
+        let compiled = compile!(
+            debug
+            r#"
+            fn getPair() {
+                return (5, 15);
+            };
+            let (x, _) = getPair();
+            "#
+        );
+
+        assert_eq!(
+            compiled,
+            indoc! {
+                "
+                j main
+                getPair:
+                push ra
+                push 5
+                push 15
+                move r15 1
+                j __internal_L1
+                __internal_L1:
+                pop ra
+                j ra
+                main:
+                jal getPair
+                pop r8
+                "
+            }
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_tuple_return_three_elements() -> anyhow::Result<()> {
+        let compiled = compile!(
+            debug
+            r#"
+            fn getTriple() {
+                return (1, 2, 3);
+            };
+            let (a, b, c) = getTriple();
+            "#
+        );
+
+        assert_eq!(
+            compiled,
+            indoc! {
+                "
+                j main
+                getTriple:
+                push ra
+                push 1
+                push 2
+                push 3
+                move r15 1
+                j __internal_L1
+                __internal_L1:
+                pop ra
+                j ra
+                main:
+                jal getTriple
+                pop r10
+                pop r9
+                pop r8
+                "
+            }
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_tuple_return_assignment() -> anyhow::Result<()> {
+        let compiled = compile!(
+            debug
+            r#"
+            fn getPair() {
+                return (42, 84);
+            };
+            let i = 0;
+            let j = 0;
+            (i, j) = getPair();
+            "#
+        );
+
+        assert_eq!(
+            compiled,
+            indoc! {
+                "
+                j main
+                getPair:
+                push ra
+                push 42
+                push 84
+                move r15 1
+                j __internal_L1
+                __internal_L1:
+                pop ra
+                j ra
+                main:
+                move r8 0
+                move r9 0
+                push r8
+                push r9
+                jal getPair
+                pop r9
+                pop r8
+                pop r9
+                pop r8
+                "
+            }
+        );
+
+        Ok(())
+    }
+}

rust_compiler/libs/compiler/src/v1.rs

@@ -9,7 +9,8 @@ use parser::{
         AssignmentExpression, BinaryExpression, BlockExpression, ConstDeclarationExpression,
         DeviceDeclarationExpression, Expression, FunctionExpression, IfExpression,
         InvocationExpression, Literal, LiteralOr, LiteralOrVariable, LogicalExpression,
-        LoopExpression, MemberAccessExpression, Spanned, TernaryExpression, WhileExpression,
+        LoopExpression, MemberAccessExpression, Spanned, TernaryExpression,
+        TupleAssignmentExpression, TupleDeclarationExpression, WhileExpression,
     },
 };
 use rust_decimal::Decimal;
@@ -465,6 +466,14 @@ impl<'a> Compiler<'a> {
                     temp_name: Some(result_name),
                 }))
             }
+            Expression::TupleDeclaration(tuple_decl) => {
+                self.expression_tuple_declaration(tuple_decl.node, scope)?;
+                Ok(None)
+            }
+            Expression::TupleAssignment(tuple_assign) => {
+                self.expression_tuple_assignment(tuple_assign.node, scope)?;
+                Ok(None)
+            }
             _ => Err(Error::Unknown(
                 format!(
                     "Expression type not yet supported in general expression context: {:?}",
@@ -932,6 +941,591 @@ impl<'a> Compiler<'a> {
         Ok(())
     }
 
+    fn expression_function_invocation_with_invocation(
+        &mut self,
+        invoke_expr: &InvocationExpression<'a>,
+        parent_scope: &mut VariableScope<'a, '_>,
+    ) -> Result<(), Error<'a>> {
+        let InvocationExpression { name, arguments } = invoke_expr;
+
+        if !self.function_locations.contains_key(name.node.as_ref()) {
+            self.errors
+                .push(Error::UnknownIdentifier(name.node.clone(), name.span));
+            return Ok(());
+        }
+
+        let Some(args) = self.function_metadata.get(name.node.as_ref()) else {
+            return Err(Error::UnknownIdentifier(name.node.clone(), name.span));
+        };
+
+        if args.len() != arguments.len() {
+            self.errors
+                .push(Error::AgrumentMismatch(name.node.clone(), name.span));
+            return Ok(());
+        }
+        let mut stack = VariableScope::scoped(parent_scope);
+
+        // backup all used registers to the stack
+        let active_registers = stack.registers();
+        for register in &active_registers {
+            stack.add_variable(
+                Cow::from(format!("temp_{register}")),
+                LocationRequest::Stack,
+                None,
+            )?;
+            self.write_instruction(
+                Instruction::Push(Operand::Register(*register)),
+                Some(name.span),
+            )?;
+        }
+        for arg in arguments {
+            match &arg.node {
+                Expression::Literal(spanned_lit) => match &spanned_lit.node {
+                    Literal::Number(num) => {
+                        self.write_instruction(
+                            Instruction::Push(Operand::Number((*num).into())),
+                            Some(spanned_lit.span),
+                        )?;
+                    }
+                    Literal::Boolean(b) => {
+                        self.write_instruction(
+                            Instruction::Push(Operand::Number(Number::from(*b).into())),
+                            Some(spanned_lit.span),
+                        )?;
+                    }
+                    _ => {}
+                },
+                Expression::Variable(var_name) => {
+                    let loc = match stack.get_location_of(&var_name.node, Some(var_name.span)) {
+                        Ok(l) => l,
+                        Err(_) => {
+                            self.errors.push(Error::UnknownIdentifier(
+                                var_name.node.clone(),
+                                var_name.span,
+                            ));
+                            VariableLocation::Temporary(0)
+                        }
+                    };
+
+                    match loc {
+                        VariableLocation::Persistant(reg) | VariableLocation::Temporary(reg) => {
+                            self.write_instruction(
+                                Instruction::Push(Operand::Register(reg)),
+                                Some(var_name.span),
+                            )?;
+                        }
+                        VariableLocation::Constant(lit) => {
+                            self.write_instruction(
+                                Instruction::Push(extract_literal(lit, false)?),
+                                Some(var_name.span),
+                            )?;
+                        }
+                        VariableLocation::Stack(stack_offset) => {
+                            self.write_instruction(
+                                Instruction::Sub(
+                                    Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                    Operand::StackPointer,
+                                    Operand::Number(stack_offset.into()),
+                                ),
+                                Some(var_name.span),
+                            )?;
+
+                            self.write_instruction(
+                                Instruction::Get(
+                                    Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                    Operand::Device(Cow::from("db")),
+                                    Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                ),
+                                Some(var_name.span),
+                            )?;
+
+                            self.write_instruction(
+                                Instruction::Push(Operand::Register(
+                                    VariableScope::TEMP_STACK_REGISTER,
+                                )),
+                                Some(var_name.span),
+                            )?;
+                        }
+                        VariableLocation::Device(_) => {
+                            self.errors.push(Error::Unknown(
+                                "Device references not supported in function arguments".into(),
+                                Some(var_name.span),
+                            ));
+                        }
+                    }
+                }
+                _ => {
+                    self.errors.push(Error::Unknown(
+                        "Only literals and variables supported in function arguments".into(),
+                        Some(arg.span),
+                    ));
+                }
+            }
+        }
+
+        let Some(_location) = self.function_locations.get(&name.node) else {
+            self.errors
+                .push(Error::UnknownIdentifier(name.node.clone(), name.span));
+            return Ok(());
+        };
+
+        self.write_instruction(
+            Instruction::JumpAndLink(Operand::Label(name.node.clone())),
+            Some(name.span),
+        )?;
+
+        // pop all registers back
+        for register in active_registers.iter().rev() {
+            self.write_instruction(
+                Instruction::Pop(Operand::Register(*register)),
+                Some(name.span),
+            )?;
+        }
+
+        Ok(())
+    }
+
+    fn expression_tuple_declaration(
+        &mut self,
+        tuple_decl: TupleDeclarationExpression<'a>,
+        scope: &mut VariableScope<'a, '_>,
+    ) -> Result<(), Error<'a>> {
+        let TupleDeclarationExpression { names, value } = tuple_decl;
+
+        // Compile the right-hand side expression
+        // For function calls returning tuples:
+        // r15 = pointer to beginning of tuple on stack
+        // r14, r13, ... contain the tuple elements, or they're on the stack
+        match &value.node {
+            Expression::Invocation(invoke_expr) => {
+                // Execute the function call
+                // Tuple values are on the stack, sp points after the last pushed value
+                // Pop them in reverse order (from end to beginning)
+                self.expression_function_invocation_with_invocation(invoke_expr, scope)?;
+
+                // First pass: allocate variables in order
+                let mut var_locations = Vec::new();
+                for name_spanned in names.iter() {
+                    // Skip underscores
+                    if name_spanned.node.as_ref() == "_" {
+                        var_locations.push(None);
+                        continue;
+                    }
+
+                    // Add variable to scope
+                    let var_location = scope.add_variable(
+                        name_spanned.node.clone(),
+                        LocationRequest::Persist,
+                        Some(name_spanned.span),
+                    )?;
+                    var_locations.push(Some(var_location));
+                }
+
+                // Second pass: pop in reverse order and assign to locations
+                for (idx, var_loc_opt) in var_locations.iter().enumerate().rev() {
+                    if let Some(var_location) = var_loc_opt {
+                        let var_reg = self.resolve_register(&var_location)?;
+
+                        // Pop from stack into the variable's register
+                        self.write_instruction(
+                            Instruction::Pop(Operand::Register(var_reg)),
+                            Some(names[idx].span),
+                        )?;
+                    }
+                }
+            }
+            Expression::Tuple(tuple_expr) => {
+                // Direct tuple literal: (value1, value2, ...)
+                let tuple_elements = &tuple_expr.node;
+
+                // Validate tuple size matches names
+                if tuple_elements.len() != names.len() {
+                    return Err(Error::Unknown(
+                        format!(
+                            "Tuple size mismatch: expected {} elements, got {}",
+                            names.len(),
+                            tuple_elements.len()
+                        ),
+                        Some(value.span),
+                    ));
+                }
+
+                // Compile each element and assign to corresponding variable
+                for (_index, (name_spanned, element)) in
+                    names.iter().zip(tuple_elements.iter()).enumerate()
+                {
+                    // Skip underscores
+                    if name_spanned.node.as_ref() == "_" {
+                        continue;
+                    }
+
+                    // Add variable to scope
+                    let var_location = scope.add_variable(
+                        name_spanned.node.clone(),
+                        LocationRequest::Persist,
+                        Some(name_spanned.span),
+                    )?;
+
+                    // Compile the element expression - handle common cases directly
+                    match &element.node {
+                        Expression::Literal(lit) => {
+                            let value_operand = extract_literal(lit.node.clone(), false)?;
+                            self.emit_variable_assignment(&var_location, value_operand)?;
+                        }
+                        Expression::Variable(var) => {
+                            let var_loc = match scope.get_location_of(&var.node, Some(var.span)) {
+                                Ok(l) => l,
+                                Err(_) => {
+                                    self.errors
+                                        .push(Error::UnknownIdentifier(var.node.clone(), var.span));
+                                    VariableLocation::Temporary(0)
+                                }
+                            };
+
+                            let value_operand = match &var_loc {
+                                VariableLocation::Temporary(reg)
+                                | VariableLocation::Persistant(reg) => Operand::Register(*reg),
+                                VariableLocation::Constant(lit) => {
+                                    extract_literal(lit.clone(), false)?
+                                }
+                                VariableLocation::Stack(offset) => {
+                                    self.write_instruction(
+                                        Instruction::Sub(
+                                            Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                            Operand::StackPointer,
+                                            Operand::Number((*offset).into()),
+                                        ),
+                                        Some(var.span),
+                                    )?;
+
+                                    self.write_instruction(
+                                        Instruction::Get(
+                                            Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                            Operand::Device(Cow::from("db")),
+                                            Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                        ),
+                                        Some(var.span),
+                                    )?;
+
+                                    Operand::Register(VariableScope::TEMP_STACK_REGISTER)
+                                }
+                                VariableLocation::Device(_) => {
+                                    return Err(Error::Unknown(
+                                        "Device values not supported in tuple literals".into(),
+                                        Some(var.span),
+                                    ));
+                                }
+                            };
+
+                            self.emit_variable_assignment(&var_location, value_operand)?;
+                        }
+                        _ => {
+                            return Err(Error::Unknown(
+                                "Complex expressions in tuple literals not yet supported".into(),
+                                Some(element.span),
+                            ));
+                        }
+                    }
+                }
+            }
+            _ => {
+                return Err(Error::Unknown(
+                    "Tuple declaration only supports function invocations or tuple literals as RHS"
+                        .into(),
+                    Some(value.span),
+                ));
+            }
+        }
+
+        Ok(())
+    }
+
+    fn expression_tuple_assignment(
+        &mut self,
+        tuple_assign: TupleAssignmentExpression<'a>,
+        scope: &mut VariableScope<'a, '_>,
+    ) -> Result<(), Error<'a>> {
+        let TupleAssignmentExpression { names, value } = tuple_assign;
+
+        // Similar to tuple declaration, but variables must already exist
+        match &value.node {
+            Expression::Invocation(invoke_expr) => {
+                // Execute the function call
+                // Tuple values are on the stack, sp points after the last pushed value
+                // Pop them in reverse order (from end to beginning)
+                self.expression_function_invocation_with_invocation(invoke_expr, scope)?;
+
+                // First pass: look up variable locations
+                let mut var_locs = Vec::new();
+                for name_spanned in names.iter() {
+                    // Skip underscores
+                    if name_spanned.node.as_ref() == "_" {
+                        var_locs.push(None);
+                        continue;
+                    }
+
+                    // Get the existing variable location
+                    let var_location =
+                        match scope.get_location_of(&name_spanned.node, Some(name_spanned.span)) {
+                            Ok(l) => l,
+                            Err(_) => {
+                                self.errors.push(Error::UnknownIdentifier(
+                                    name_spanned.node.clone(),
+                                    name_spanned.span,
+                                ));
+                                VariableLocation::Temporary(0)
+                            }
+                        };
+                    var_locs.push(Some(var_location));
+                }
+
+                // Second pass: pop in reverse order and assign
+                for (idx, var_loc_opt) in var_locs.iter().enumerate().rev() {
+                    if let Some(var_location) = var_loc_opt {
+                        // Pop from stack and assign to variable
+                        match var_location {
+                            VariableLocation::Temporary(reg)
+                            | VariableLocation::Persistant(reg) => {
+                                // Pop directly into the variable's register
+                                self.write_instruction(
+                                    Instruction::Pop(Operand::Register(*reg)),
+                                    Some(names[idx].span),
+                                )?;
+                            }
+                            VariableLocation::Stack(offset) => {
+                                // Pop into temp register, then write to variable stack
+                                self.write_instruction(
+                                    Instruction::Pop(Operand::Register(
+                                        VariableScope::TEMP_STACK_REGISTER,
+                                    )),
+                                    Some(names[idx].span),
+                                )?;
+
+                                // Write to variable stack location
+                                self.write_instruction(
+                                    Instruction::Sub(
+                                        Operand::Register(0),
+                                        Operand::StackPointer,
+                                        Operand::Number((*offset).into()),
+                                    ),
+                                    Some(names[idx].span),
+                                )?;
+
+                                self.write_instruction(
+                                    Instruction::Put(
+                                        Operand::Device(Cow::from("db")),
+                                        Operand::Register(0),
+                                        Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                    ),
+                                    Some(names[idx].span),
+                                )?;
+                            }
+                            VariableLocation::Constant(_) => {
+                                return Err(Error::ConstAssignment(
+                                    names[idx].node.clone(),
+                                    names[idx].span,
+                                ));
+                            }
+                            VariableLocation::Device(_) => {
+                                return Err(Error::DeviceAssignment(
+                                    names[idx].node.clone(),
+                                    names[idx].span,
+                                ));
+                            }
+                        }
+                    }
+                }
+            }
+            Expression::Tuple(tuple_expr) => {
+                // Direct tuple literal: (value1, value2, ...)
+                let tuple_elements = &tuple_expr.node;
+
+                // Validate tuple size matches names
+                if tuple_elements.len() != names.len() {
+                    return Err(Error::Unknown(
+                        format!(
+                            "Tuple size mismatch: expected {} elements, got {}",
+                            names.len(),
+                            tuple_elements.len()
+                        ),
+                        Some(value.span),
+                    ));
+                }
+
+                // Compile each element and assign to corresponding variable
+                for (_index, (name_spanned, element)) in
+                    names.iter().zip(tuple_elements.iter()).enumerate()
+                {
+                    // Skip underscores
+                    if name_spanned.node.as_ref() == "_" {
+                        continue;
+                    }
+
+                    // Get the existing variable location
+                    let var_location =
+                        match scope.get_location_of(&name_spanned.node, Some(name_spanned.span)) {
+                            Ok(l) => l,
+                            Err(_) => {
+                                self.errors.push(Error::UnknownIdentifier(
+                                    name_spanned.node.clone(),
+                                    name_spanned.span,
+                                ));
+                                VariableLocation::Temporary(0)
+                            }
+                        };
+
+                    // Compile the element expression - handle common cases directly
+                    match &element.node {
+                        Expression::Literal(lit) => {
+                            let value_operand = extract_literal(lit.node.clone(), false)?;
+                            match &var_location {
+                                VariableLocation::Temporary(reg)
+                                | VariableLocation::Persistant(reg) => {
+                                    self.write_instruction(
+                                        Instruction::Move(Operand::Register(*reg), value_operand),
+                                        Some(name_spanned.span),
+                                    )?;
+                                }
+                                VariableLocation::Stack(offset) => {
+                                    self.write_instruction(
+                                        Instruction::Sub(
+                                            Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                            Operand::StackPointer,
+                                            Operand::Number((*offset).into()),
+                                        ),
+                                        Some(name_spanned.span),
+                                    )?;
+
+                                    self.write_instruction(
+                                        Instruction::Put(
+                                            Operand::Device(Cow::from("db")),
+                                            Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                            value_operand,
+                                        ),
+                                        Some(name_spanned.span),
+                                    )?;
+                                }
+                                VariableLocation::Constant(_) => {
+                                    return Err(Error::ConstAssignment(
+                                        name_spanned.node.clone(),
+                                        name_spanned.span,
+                                    ));
+                                }
+                                VariableLocation::Device(_) => {
+                                    return Err(Error::DeviceAssignment(
+                                        name_spanned.node.clone(),
+                                        name_spanned.span,
+                                    ));
+                                }
+                            }
+                        }
+                        Expression::Variable(var) => {
+                            let var_loc = match scope.get_location_of(&var.node, Some(var.span)) {
+                                Ok(l) => l,
+                                Err(_) => {
+                                    self.errors
+                                        .push(Error::UnknownIdentifier(var.node.clone(), var.span));
+                                    VariableLocation::Temporary(0)
+                                }
+                            };
+
+                            let value_operand = match &var_loc {
+                                VariableLocation::Temporary(reg)
+                                | VariableLocation::Persistant(reg) => Operand::Register(*reg),
+                                VariableLocation::Constant(lit) => {
+                                    extract_literal(lit.clone(), false)?
+                                }
+                                VariableLocation::Stack(offset) => {
+                                    self.write_instruction(
+                                        Instruction::Sub(
+                                            Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                            Operand::StackPointer,
+                                            Operand::Number((*offset).into()),
+                                        ),
+                                        Some(var.span),
+                                    )?;
+
+                                    self.write_instruction(
+                                        Instruction::Get(
+                                            Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                            Operand::Device(Cow::from("db")),
+                                            Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                        ),
+                                        Some(var.span),
+                                    )?;
+
+                                    Operand::Register(VariableScope::TEMP_STACK_REGISTER)
+                                }
+                                VariableLocation::Device(_) => {
+                                    return Err(Error::Unknown(
+                                        "Device values not supported in tuple literals".into(),
+                                        Some(var.span),
+                                    ));
+                                }
+                            };
+
+                            match &var_location {
+                                VariableLocation::Temporary(reg)
+                                | VariableLocation::Persistant(reg) => {
+                                    self.write_instruction(
+                                        Instruction::Move(Operand::Register(*reg), value_operand),
+                                        Some(name_spanned.span),
+                                    )?;
+                                }
+                                VariableLocation::Stack(offset) => {
+                                    self.write_instruction(
+                                        Instruction::Sub(
+                                            Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                            Operand::StackPointer,
+                                            Operand::Number((*offset).into()),
+                                        ),
+                                        Some(name_spanned.span),
+                                    )?;
+
+                                    self.write_instruction(
+                                        Instruction::Put(
+                                            Operand::Device(Cow::from("db")),
+                                            Operand::Register(VariableScope::TEMP_STACK_REGISTER),
+                                            value_operand,
+                                        ),
+                                        Some(name_spanned.span),
+                                    )?;
+                                }
+                                VariableLocation::Constant(_) => {
+                                    return Err(Error::ConstAssignment(
+                                        name_spanned.node.clone(),
+                                        name_spanned.span,
+                                    ));
+                                }
+                                VariableLocation::Device(_) => {
+                                    return Err(Error::DeviceAssignment(
+                                        name_spanned.node.clone(),
+                                        name_spanned.span,
+                                    ));
+                                }
+                            }
+                        }
+                        _ => {
+                            return Err(Error::Unknown(
+                                "Complex expressions in tuple literals not yet supported".into(),
+                                Some(element.span),
+                            ));
+                        }
+                    }
+                }
+            }
+            _ => {
+                return Err(Error::Unknown(
+                    "Tuple assignment only supports function invocations or tuple literals as RHS"
+                        .into(),
+                    Some(value.span),
+                ));
+            }
+        }
+
+        Ok(())
+    }
+
     fn expression_function_invocation(
         &mut self,
         invoke_expr: Spanned<InvocationExpression<'a>>,
@@ -1946,6 +2540,110 @@ impl<'a> Compiler<'a> {
                         }
                     }
                 }
+                Expression::Tuple(tuple_expr) => {
+                    let span = expr.span;
+                    let tuple_elements = &tuple_expr.node;
+
+                    // Record the stack offset where the tuple will start
+                    let tuple_start_offset = scope.stack_offset();
+
+                    // Allocate space on the stack for each tuple element
+                    for element in tuple_elements.iter() {
+                        match &element.node {
+                            Expression::Literal(lit) => {
+                                let value_operand = extract_literal(lit.node.clone(), false)?;
+                                self.write_instruction(
+                                    Instruction::Push(value_operand),
+                                    Some(span),
+                                )?;
+                            }
+                            Expression::Variable(var) => {
+                                let var_loc = match scope.get_location_of(&var.node, Some(var.span))
+                                {
+                                    Ok(l) => l,
+                                    Err(_) => {
+                                        self.errors.push(Error::UnknownIdentifier(
+                                            var.node.clone(),
+                                            var.span,
+                                        ));
+                                        VariableLocation::Temporary(0)
+                                    }
+                                };
+
+                                match &var_loc {
+                                    VariableLocation::Temporary(reg)
+                                    | VariableLocation::Persistant(reg) => {
+                                        self.write_instruction(
+                                            Instruction::Push(Operand::Register(*reg)),
+                                            Some(span),
+                                        )?;
+                                    }
+                                    VariableLocation::Constant(lit) => {
+                                        let value_operand = extract_literal(lit.clone(), false)?;
+                                        self.write_instruction(
+                                            Instruction::Push(value_operand),
+                                            Some(span),
+                                        )?;
+                                    }
+                                    VariableLocation::Stack(offset) => {
+                                        self.write_instruction(
+                                            Instruction::Sub(
+                                                Operand::Register(
+                                                    VariableScope::TEMP_STACK_REGISTER,
+                                                ),
+                                                Operand::StackPointer,
+                                                Operand::Number((*offset).into()),
+                                            ),
+                                            Some(span),
+                                        )?;
+                                        self.write_instruction(
+                                            Instruction::Get(
+                                                Operand::Register(
+                                                    VariableScope::TEMP_STACK_REGISTER,
+                                                ),
+                                                Operand::Device(Cow::from("db")),
+                                                Operand::Register(
+                                                    VariableScope::TEMP_STACK_REGISTER,
+                                                ),
+                                            ),
+                                            Some(span),
+                                        )?;
+                                        self.write_instruction(
+                                            Instruction::Push(Operand::Register(
+                                                VariableScope::TEMP_STACK_REGISTER,
+                                            )),
+                                            Some(span),
+                                        )?;
+                                    }
+                                    VariableLocation::Device(_) => {
+                                        return Err(Error::Unknown(
+                                            "You can not return a device from a function.".into(),
+                                            Some(var.span),
+                                        ));
+                                    }
+                                }
+                            }
+                            _ => {
+                                // For complex expressions, just push 0 for now
+                                self.write_instruction(
+                                    Instruction::Push(Operand::Number(
+                                        Number::Integer(0, Unit::None).into(),
+                                    )),
+                                    Some(span),
+                                )?;
+                            }
+                        }
+                    }
+
+                    // Store the pointer to the tuple (stack offset) in r15
+                    self.write_instruction(
+                        Instruction::Move(
+                            Operand::Register(VariableScope::RETURN_REGISTER),
+                            Operand::Number(tuple_start_offset.into()),
+                        ),
+                        Some(span),
+                    )?;
+                }
                 _ => {
                     return Err(Error::Unknown(
                         format!("Unsupported `return` statement: {:?}", expr),

rust_compiler/libs/parser/src/lib.rs

@@ -441,7 +441,13 @@ impl<'a> Parser<'a> {
                 ));
             }
 
-            TokenType::Keyword(Keyword::Let) => Some(self.spanned(|p| p.declaration())?),
+            TokenType::Keyword(Keyword::Let) => {
+                if self_matches_peek!(self, TokenType::Symbol(Symbol::LParen)) {
+                    Some(self.spanned(|p| p.tuple_declaration())?)
+                } else {
+                    Some(self.spanned(|p| p.declaration())?)
+                }
+            }
 
             TokenType::Keyword(Keyword::Device) => {
                 let spanned_dev = self.spanned(|p| p.device())?;
@@ -561,9 +567,7 @@ impl<'a> Parser<'a> {
                 })
             }
 
-            TokenType::Symbol(Symbol::LParen) => {
+            TokenType::Symbol(Symbol::LParen) => self.parenthesized_or_tuple()?,
-                self.spanned(|p| p.priority())?.node.map(|node| *node)
-            }
 
             TokenType::Symbol(Symbol::Minus) => {
                 let start_span = self.current_span();
@@ -642,8 +646,8 @@ impl<'a> Parser<'a> {
                 }
             }
             TokenType::Symbol(Symbol::LParen) => *self
-                .spanned(|p| p.priority())?
+                .parenthesized_or_tuple()?
-                .node
+                .map(Box::new)
                 .ok_or(Error::UnexpectedEOF)?,
 
             TokenType::Identifier(ref id) if SysCall::is_syscall(id) => {
@@ -774,7 +778,8 @@ impl<'a> Parser<'a> {
             | Expression::Ternary(_)
             | Expression::Negation(_)
             | Expression::MemberAccess(_)
-            | Expression::MethodCall(_) => {}
+            | Expression::MethodCall(_)
+            | Expression::Tuple(_) => {}
             _ => {
                 return Err(Error::InvalidSyntax(
                     self.current_span(),
@@ -1081,17 +1086,43 @@ impl<'a> Parser<'a> {
                     end_col: right.span.end_col,
                 };
 
+                // Check if the left side is a tuple, and if so, create a TupleAssignment
+                let node = if let Expression::Tuple(tuple_expr) = &left.node {
+                    // Extract variable names from the tuple, handling underscores
+                    let mut names = Vec::new();
+                    for item in &tuple_expr.node {
+                        if let Expression::Variable(var) = &item.node {
+                            names.push(var.clone());
+                        } else {
+                            return Err(Error::InvalidSyntax(
+                                item.span,
+                                String::from("Tuple assignment can only contain variable names"),
+                            ));
+                        }
+                    }
+                    
+                    Expression::TupleAssignment(Spanned {
+                        span,
+                        node: TupleAssignmentExpression {
+                            names,
+                            value: boxed!(right),
+                        },
+                    })
+                } else {
+                    Expression::Assignment(Spanned {
+                        span,
+                        node: AssignmentExpression {
+                            assignee: boxed!(left),
+                            expression: boxed!(right),
+                        },
+                    })
+                };
+
                 expressions.insert(
                     i,
                     Spanned {
                         span,
-                        node: Expression::Assignment(Spanned {
+                        node,
-                            span,
-                            node: AssignmentExpression {
-                                assignee: boxed!(left),
-                                expression: boxed!(right),
-                            },
-                        }),
                     },
                 );
             }
@@ -1117,8 +1148,12 @@ impl<'a> Parser<'a> {
         expressions.pop().ok_or(Error::UnexpectedEOF)
     }
 
-    fn priority(&mut self) -> Result<Option<Box<Spanned<Expression<'a>>>>, Error<'a>> {
+    fn parenthesized_or_tuple(
+        &mut self,
+    ) -> Result<Option<Spanned<tree_node::Expression<'a>>>, Error<'a>> {
+        let start_span = self.current_span();
         let current_token = self.current_token.as_ref().ok_or(Error::UnexpectedEOF)?;
+
         if !token_matches!(current_token, TokenType::Symbol(Symbol::LParen)) {
             return Err(Error::UnexpectedToken(
                 self.current_span(),
@@ -1127,17 +1162,113 @@ impl<'a> Parser<'a> {
         }
 
         self.assign_next()?;
-        let expression = self.expression()?.ok_or(Error::UnexpectedEOF)?;
 
-        let current_token = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+        // Handle empty tuple '()'
-        if !token_matches!(current_token, TokenType::Symbol(Symbol::RParen)) {
+        if self_matches_peek!(self, TokenType::Symbol(Symbol::RParen)) {
-            return Err(Error::UnexpectedToken(
+            self.assign_next()?;
-                Self::token_to_span(&current_token),
+            let end_span = self.current_span();
-                current_token,
+            let span = Span {
-            ));
+                start_line: start_span.start_line,
+                start_col: start_span.start_col,
+                end_line: end_span.end_line,
+                end_col: end_span.end_col,
+            };
+            return Ok(Some(Spanned {
+                span,
+                node: Expression::Tuple(Spanned { span, node: vec![] }),
+            }));
         }
 
-        Ok(Some(boxed!(expression)))
+        let first_expression = self.expression()?.ok_or(Error::UnexpectedEOF)?;
+
+        if self_matches_peek!(self, TokenType::Symbol(Symbol::Comma)) {
+            // It is a tuple
+            let mut items = vec![first_expression];
+            while self_matches_peek!(self, TokenType::Symbol(Symbol::Comma)) {
+                // Next toekn is a comma, we need to consume it and advance 1 more time.
+                self.assign_next()?;
+                self.assign_next()?;
+                println!("{:?}", self.current_token);
+                items.push(self.expression()?.ok_or(Error::UnexpectedEOF)?);
+            }
+
+            let next = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+            if !token_matches!(next, TokenType::Symbol(Symbol::RParen)) {
+                return Err(Error::UnexpectedToken(Self::token_to_span(&next), next));
+            }
+
+            let end_span = Self::token_to_span(&next);
+            let span = Span {
+                start_line: start_span.start_line,
+                start_col: start_span.start_col,
+                end_line: end_span.end_line,
+                end_col: end_span.end_col,
+            };
+
+            Ok(Some(Spanned {
+                span,
+                node: Expression::Tuple(Spanned { span, node: items }),
+            }))
+        } else {
+            // It is just priority
+            let next = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+            if !token_matches!(next, TokenType::Symbol(Symbol::RParen)) {
+                return Err(Error::UnexpectedToken(Self::token_to_span(&next), next));
+            }
+
+            Ok(Some(Spanned {
+                span: first_expression.span,
+                node: Expression::Priority(boxed!(first_expression)),
+            }))
+        }
+    }
+
+    fn tuple_declaration(&mut self) -> Result<Expression<'a>, Error<'a>> {
+        // 'let' is consumed before this call
+        // expect '('
+        let next = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+        if !token_matches!(next, TokenType::Symbol(Symbol::LParen)) {
+            return Err(Error::UnexpectedToken(Self::token_to_span(&next), next));
+        }
+
+        let mut names = Vec::new();
+        while !self_matches_peek!(self, TokenType::Symbol(Symbol::RParen)) {
+            let token = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+            let span = Self::token_to_span(&token);
+            if let TokenType::Identifier(id) = token.token_type {
+                names.push(Spanned { span, node: id });
+            } else {
+                return Err(Error::UnexpectedToken(span, token));
+            }
+
+            if self_matches_peek!(self, TokenType::Symbol(Symbol::Comma)) {
+                self.assign_next()?;
+            }
+        }
+        self.assign_next()?; // consume ')'
+
+        let assign = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+
+        if !token_matches!(assign, TokenType::Symbol(Symbol::Assign)) {
+            return Err(Error::UnexpectedToken(Self::token_to_span(&assign), assign));
+        }
+
+        self.assign_next()?; // Consume the `=`
+
+        let value = self.expression()?.ok_or(Error::UnexpectedEOF)?;
+
+        let semi = self.get_next()?.ok_or(Error::UnexpectedEOF)?;
+        if !token_matches!(semi, TokenType::Symbol(Symbol::Semicolon)) {
+            return Err(Error::UnexpectedToken(Self::token_to_span(&semi), semi));
+        }
+
+        Ok(Expression::TupleDeclaration(Spanned {
+            span: names.first().map(|n| n.span).unwrap_or(value.span),
+            node: TupleDeclarationExpression {
+                names,
+                value: boxed!(value),
+            },
+        }))
     }
 
     fn invocation(&mut self) -> Result<InvocationExpression<'a>, Error<'a>> {

rust_compiler/libs/parser/src/test/mod.rs

@@ -112,7 +112,7 @@ fn test_function_invocation() -> Result<()> {
 #[test]
 fn test_priority_expression() -> Result<()> {
     let input = r#"
-            let x = (4);
+            let x = (4 + 3);
         "#;
 
     let tokenizer = Tokenizer::from(input);
@@ -120,7 +120,7 @@ fn test_priority_expression() -> Result<()> {
 
     let expression = parser.parse()?.unwrap();
 
-    assert_eq!("(let x = 4)", expression.to_string());
+    assert_eq!("(let x = ((4 + 3)))", expression.to_string());
 
     Ok(())
 }
@@ -137,7 +137,7 @@ fn test_binary_expression() -> Result<()> {
     assert_eq!("(((45 * 2) - (15 / 5)) + (5 ** 2))", expr.to_string());
 
     let expr = parser!("(5 - 2) * 10;").parse()?.unwrap();
-    assert_eq!("((5 - 2) * 10)", expr.to_string());
+    assert_eq!("(((5 - 2)) * 10)", expr.to_string());
 
     Ok(())
 }
@@ -170,7 +170,7 @@ fn test_ternary_expression() -> Result<()> {
 fn test_complex_binary_with_ternary() -> Result<()> {
     let expr = parser!("let i = (x ? 1 : 3) * 2;").parse()?.unwrap();
 
-    assert_eq!("(let i = ((x ? 1 : 3) * 2))", expr.to_string());
+    assert_eq!("(let i = (((x ? 1 : 3)) * 2))", expr.to_string());
 
     Ok(())
 }
@@ -191,3 +191,65 @@ fn test_nested_ternary_right_associativity() -> Result<()> {
     assert_eq!("(let i = (a ? b : (c ? d : e)))", expr.to_string());
     Ok(())
 }
+
+#[test]
+fn test_tuple_declaration() -> Result<()> {
+    let expr = parser!("let (x, _) = (1, 2);").parse()?.unwrap();
+
+    assert_eq!("(let (x, _) = (1, 2))", expr.to_string());
+
+    Ok(())
+}
+#[test]
+fn test_tuple_assignment() -> Result<()> {
+    let expr = parser!("(x, y) = (1, 2);").parse()?.unwrap();
+
+    assert_eq!("((x, y) = (1, 2))", expr.to_string());
+
+    Ok(())
+}
+
+#[test]
+fn test_tuple_assignment_with_underscore() -> Result<()> {
+    let expr = parser!("(x, _) = (1, 2);").parse()?.unwrap();
+
+    assert_eq!("((x, _) = (1, 2))", expr.to_string());
+
+    Ok(())
+}
+
+#[test]
+fn test_tuple_declaration_with_function_call() -> Result<()> {
+    let expr = parser!("let (x, y) = doSomething();").parse()?.unwrap();
+
+    assert_eq!("(let (x, y) = doSomething())", expr.to_string());
+
+    Ok(())
+}
+
+#[test]
+fn test_tuple_declaration_with_function_call_with_underscore() -> Result<()> {
+    let expr = parser!("let (x, _) = doSomething();").parse()?.unwrap();
+
+    assert_eq!("(let (x, _) = doSomething())", expr.to_string());
+
+    Ok(())
+}
+
+#[test]
+fn test_tuple_assignment_with_function_call() -> Result<()> {
+    let expr = parser!("(x, y) = doSomething();").parse()?.unwrap();
+
+    assert_eq!("((x, y) = doSomething())", expr.to_string());
+
+    Ok(())
+}
+
+#[test]
+fn test_tuple_assignment_with_function_call_with_underscore() -> Result<()> {
+    let expr = parser!("(x, _) = doSomething();").parse()?.unwrap();
+
+    assert_eq!("((x, _) = doSomething())", expr.to_string());
+
+    Ok(())
+}

rust_compiler/libs/parser/src/tree_node.rs

@@ -245,6 +245,42 @@ impl<'a> std::fmt::Display for DeviceDeclarationExpression<'a> {
     }
 }
 
+#[derive(Debug, PartialEq, Eq)]
+pub struct TupleDeclarationExpression<'a> {
+    pub names: Vec<Spanned<Cow<'a, str>>>,
+    pub value: Box<Spanned<Expression<'a>>>,
+}
+
+impl<'a> std::fmt::Display for TupleDeclarationExpression<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let names = self
+            .names
+            .iter()
+            .map(|n| n.node.to_string())
+            .collect::<Vec<_>>()
+            .join(", ");
+        write!(f, "(let ({}) = {})", names, self.value)
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct TupleAssignmentExpression<'a> {
+    pub names: Vec<Spanned<Cow<'a, str>>>,
+    pub value: Box<Spanned<Expression<'a>>>,
+}
+
+impl<'a> std::fmt::Display for TupleAssignmentExpression<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let names = self
+            .names
+            .iter()
+            .map(|n| n.node.to_string())
+            .collect::<Vec<_>>()
+            .join(", ");
+        write!(f, "(({}) = {})", names, self.value)
+    }
+}
+
 #[derive(Debug, PartialEq, Eq)]
 pub struct IfExpression<'a> {
     pub condition: Box<Spanned<Expression<'a>>>,
@@ -348,6 +384,9 @@ pub enum Expression<'a> {
     Return(Option<Box<Spanned<Expression<'a>>>>),
     Syscall(Spanned<SysCall<'a>>),
     Ternary(Spanned<TernaryExpression<'a>>),
+    Tuple(Spanned<Vec<Spanned<Expression<'a>>>>),
+    TupleAssignment(Spanned<TupleAssignmentExpression<'a>>),
+    TupleDeclaration(Spanned<TupleDeclarationExpression<'a>>),
     Variable(Spanned<Cow<'a, str>>),
     While(Spanned<WhileExpression<'a>>),
 }
@@ -384,8 +423,20 @@ impl<'a> std::fmt::Display for Expression<'a> {
             ),
             Expression::Syscall(e) => write!(f, "{}", e),
             Expression::Ternary(e) => write!(f, "{}", e),
+            Expression::Tuple(e) => {
+                let items = e
+                    .node
+                    .iter()
+                    .map(|x| x.to_string())
+                    .collect::<Vec<_>>()
+                    .join(", ");
+                write!(f, "({})", items)
+            }
+            Expression::TupleAssignment(e) => write!(f, "{}", e),
+            Expression::TupleDeclaration(e) => write!(f, "{}", e),
             Expression::Variable(id) => write!(f, "{}", id),
             Expression::While(e) => write!(f, "{}", e),
         }
     }
 }
+