- implementation of <var> <op> = <expr> type statements such as `x +=

5` - implementation of logical and shift operations in parser and codegen. - implementation of sizeof keyword as unary operator in progress (non functional) - implementation of prefix and postfix inc/dec operators - array access by index (implemented, untested as arrays aren't implemented yet). essentially just a pointer write with offset. - struct/member access (parsing implemented, untested.)
2026-02-09 00:10:37 +00:00
parent e2be83414b
commit 22241a5633
3 changed files with 457 additions and 109 deletions
@@ -9,8 +9,8 @@ use crate::backend::dsa::registers::Register;
 use crate::{block, comment, dsa};

 use crate::model::{
-    BinaryOperator, Call, CompilerError, ConstExpr, Declaration, Dependency, Expression,
-    Program, Statement, TypeId, UnaryOperator, Variable,
+    AssignmentOperator, BinaryOperator, Call, CompilerError, ConstExpr, Declaration,
+    Dependency, Expression, Program, Statement, TypeId, UnaryOperator, Variable,
 };

 pub struct CodeGenerator {
@@ -271,24 +271,106 @@ impl CodeGenerator {
                self.allocator.free_temp(ptr_reg);
            }

-            Statement::Assign { varname, value } => {
+            Statement::Assign {
+                varname,
+                value,
+                operator,
+            } => {
                // Evaluate expression
                let (result_reg, expr_code) =
                    self.generate_expression(value, true, func_body)?;
                code.extend(expr_code);

+                if *operator == AssignmentOperator::Assign {
+                    // Check if this is a global variable
+                    if self.is_global(varname) {
+                        // Store to global label
+                        code.push(format!("\tstw {}, {}", result_reg, varname));
+                    } else {
+                        // Store result in local variable
+                        let store_code = self.allocator.store_var(varname, &result_reg);
+                        code.extend(store_code);
+                    }
+
+                    // Free temporary register
+                    self.allocator.free_temp(result_reg);
+
+                    return Ok(code);
+                }
+
+                // for more complex assignment cases we need an intermediate register.
+                let (temp_reg, temp_code) = self.allocator.alloc_temp()?;
+                code.extend(temp_code);
+
+                // fetch the value of the variable
+                let (var_reg, var_code) = if self.is_global(varname) {
+                    (temp_reg, vec![format!("\tldw {}, {}", varname, temp_reg)])
+                } else {
+                    self.allocator.load_var(varname)?
+                };
+                code.extend(var_code);
+
+                let assign_code = match operator {
+                    AssignmentOperator::Assign => {
+                        unreachable!("assignment was already checked earlier.")
+                    }
+                    AssignmentOperator::AddAssign => {
+                        format!("\tadd {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::SubAssign => {
+                        format!("\tsub {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::MulAssign => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "TODO: implement multiplication for assignment"
+                        )));
+                    }
+                    AssignmentOperator::DivAssign => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "TODO: write proper div function for DSA"
+                        )));
+                    }
+                    AssignmentOperator::ModAssign => {
+                        format!("\tmod {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::AndAssign => {
+                        format!("\tand {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::OrAssign => {
+                        format!("\tor {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::XorAssign => {
+                        format!("\txor {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::LeftShiftAssign => {
+                        // this is only useful if we optimise out the register allocation
+                        // inside value. if let Expression::Number
+                        // { value, .. } = *value {     format!("\
+                        // tshl {var_reg}, {value}, {temp_reg}") }
+                        format!("\tshl {var_reg}, {result_reg}, 0, {temp_reg}")
+                    }
+                    AssignmentOperator::RightShiftAssign => {
+                        // this is only useful if we optimise out the register allocation
+                        // if let Expression::Number { value, .. } = *value {
+                        //     format!("\tshr {var_reg}, {value}, {temp_reg}")
+                        // }
+                        format!("\tshr {var_reg}, {result_reg}, 0, {temp_reg}")
+                    }
+                };
+                code.push(assign_code);
+
                // Check if this is a global variable
                if self.is_global(varname) {
                    // Store to global label
-                    code.push(format!("\tstw {}, {}", result_reg, varname));
+                    code.push(format!("\tstw {}, {}", temp_reg, varname));
                } else {
                    // Store result in local variable
-                    let store_code = self.allocator.store_var(varname, &result_reg);
+                    let store_code = self.allocator.store_var(varname, &temp_reg);
                    code.extend(store_code);
                }

-                // Free temporary register
                self.allocator.free_temp(result_reg);
+                self.allocator.free_temp(temp_reg);
            }

            Statement::Return(expr) => {
@@ -414,16 +496,17 @@ impl CodeGenerator {
        let mut code = Vec::new();

        match expr {
-            Expression::StringLiteral(value) => {
+            Expression::Empty => Ok((Register::Null, code)),
+
+            Expression::Number { value, .. } => {
                let (reg, alloc_code) = self.allocator.alloc_temp()?;
                code.extend(alloc_code);

-                // write string into memory
-                let uuid = self.get_unique_label();
-                func_body.insert(0, format!("db str_{uuid}: \"{value}\""));
-
-                // Load pointer to string
-                code.push(format!("\tlwi str_{uuid}, {reg}"));
+                // Load immediate value
+                code.push(format!("\tlli {}, {}", value & 0xFFFF, reg));
+                if *value > 0xFFFF || *value < 0 {
+                    code.push(format!("\tlui {}, {}", (value >> 16) & 0xFFFF, reg));
+                }

                Ok((reg, code))
            }
@@ -438,19 +521,22 @@ impl CodeGenerator {
                Ok((reg, code))
            }

-            Expression::Number { value, .. } => {
+            Expression::StringLiteral(value) => {
                let (reg, alloc_code) = self.allocator.alloc_temp()?;
                code.extend(alloc_code);

-                // Load immediate value
-                code.push(format!("\tlli {}, {}", value & 0xFFFF, reg));
-                if *value > 0xFFFF || *value < 0 {
-                    code.push(format!("\tlui {}, {}", (value >> 16) & 0xFFFF, reg));
-                }
+                // write string into memory
+                let uuid = self.get_unique_label();
+                func_body.insert(0, format!("db str_{uuid}: \"{value}\""));
+
+                // Load pointer to string
+                code.push(format!("\tlwi str_{uuid}, {reg}"));

                Ok((reg, code))
            }

+            Expression::ArrayLiteral { elements, type_id } => todo!(),
+
            Expression::Variable { name, .. } => {
                if self.is_global(&name.name) {
                    // Allocate a temporary register for the global
@@ -489,16 +575,14 @@ impl CodeGenerator {
                // Generate operation
                match op {
                    BinaryOperator::Add => {
-                        code.push(format!(
-                            "\tadd {}, {}, {}",
-                            left_reg, right_reg, result_reg
-                        ));
+                        code.push(
+                            format!("\tadd {left_reg}, {right_reg}, {result_reg}",),
+                        );
                    }
                    BinaryOperator::Sub => {
-                        code.push(format!(
-                            "\tsub {}, {}, {}",
-                            left_reg, right_reg, result_reg
-                        ));
+                        code.push(
+                            format!("\tsub {left_reg}, {right_reg}, {result_reg}",),
+                        );
                    }
                    BinaryOperator::Mul => {
                        self.include("maths", "./lib/maths/core.dsa");
@@ -509,6 +593,53 @@ impl CodeGenerator {
                        code.push(format!("\tpop {}", result_reg));
                        code.push("\tpop zero".to_string());
                    }
+                    BinaryOperator::Div => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "TODO: write proper div function for DSA"
+                        )));
+                        // self.include("maths", "./lib/maths/core.dsa");
+                        // // Call divide function
+                        // code.push(format!("\tpush {}", right_reg));
+                        // code.push(format!("\tpush {}", left_reg));
+                        // code.push("\tcall maths::divide".to_string());
+                        // code.push(format!("\tpop {}", result_reg));
+                        // code.push("\tpop zero".to_string());
+                    }
+                    BinaryOperator::Mod => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "TODO: write proper mod function for DSA"
+                        )));
+                        // self.include("maths", "./lib/maths/core.dsa");
+                        // // Call modulo function
+                        // code.push(format!("\tpush {}", right_reg));
+                        // code.push(format!("\tpush {}", left_reg));
+                        // code.push("\tcall maths::modulo".to_string());
+                        // code.push(format!("\tpop {}", result_reg));
+                        // code.push("\tpop zero".to_string());
+                    }
+                    BinaryOperator::BitwiseAnd => {
+                        code.push(format!("\tand {left_reg}, {right_reg}, {result_reg}"));
+                    }
+                    BinaryOperator::BitwiseOr => {
+                        code.push(format!("\tor {left_reg}, {right_reg}, {result_reg}"));
+                    }
+                    BinaryOperator::BitwiseXor => {
+                        code.push(format!("\txor {left_reg}, {right_reg}, {result_reg}"));
+                    }
+                    BinaryOperator::LogicalAnd => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "assembler/ISA does not yet support logical and!"
+                        )));
+                    }
+                    BinaryOperator::LogicalOr => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "assembler/ISA does not yet support logical or!"
+                        )));
+                    }
+                    BinaryOperator::LeftShift => code
+                        .push(format!("\tshl {left_reg}, {right_reg}, 0, {result_reg}")),
+                    BinaryOperator::RightShift => code
+                        .push(format!("\tshr {left_reg}, {right_reg}, 0, {result_reg}")),
                    // Comparison operators - return 1 (true) or 0 (false)
                    BinaryOperator::Equal => {
                        code.push(format!("\tcmp {}, {}", left_reg, right_reg));
@@ -557,8 +688,7 @@ impl CodeGenerator {
                        code.push(format!("\tjge {}", end_label));
                        code.push(format!("\tlli 8, {}", result_reg));
                        code.push(format!("{}:", end_label));
-                    }
-                    _ => unimplemented!(),
+                    } // _ => unimplemented!(),
                }

                // Free operand registers (allocator will protect variables)
@@ -568,6 +698,105 @@ impl CodeGenerator {
                Ok((result_reg, code))
            }

+            Expression::UnaryPostfix { op, operand, .. } => {
+                let (operand_reg, operand_code) =
+                    self.generate_expression(operand, true, func_body)?;
+                code.extend(operand_code);
+
+                let (result_reg, result_alloc) = self.allocator.alloc_temp()?;
+                code.extend(result_alloc);
+
+                match op {
+                    UnaryOperator::Increment => {
+                        // prefix increment
+                        // code.push(format!("\taddi {}, 1, {}", operand_reg,
+                        // operand_reg));
+                        code.push(format!("\tmov {}, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::Decrement => {
+                        // prefix decrement
+                        // code.push(format!("\tsubi {}, 1, {}", operand_reg,
+                        // operand_reg));
+                        code.push(format!("\tmov {}, {}", operand_reg, result_reg));
+                    }
+                    _ => {
+                        return Err(CompilerError::Generic(format!(
+                            "{op} is prefix only!"
+                        )));
+                    }
+                }
+
+                self.allocator.free_temp(operand_reg);
+                Ok((result_reg, code))
+            }
+
+            Expression::Unary { op, operand, .. } => {
+                let (operand_reg, operand_code) =
+                    self.generate_expression(operand, true, func_body)?;
+                code.extend(operand_code);
+
+                let (result_reg, result_alloc) = self.allocator.alloc_temp()?;
+                code.extend(result_alloc);
+
+                match op {
+                    UnaryOperator::Minus => {
+                        // Negate: result = 0 - operand
+                        code.push(format!("\tsub zero, {}, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::Plus => {
+                        // Just move
+                        code.push(format!("\tmov {}, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::Dereference => {
+                        code.push(format!("\tldw {}, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::AddressOf => {
+                        // ensure the referenced variable is on the stack and return its
+                        // address.
+                        let (offset, alloc_code) =
+                            self.allocator.free_register(&operand_reg)?;
+                        code.extend(alloc_code);
+                        code.push(format!(
+                            "\taddi spr, {}, {}",
+                            offset - self.allocator.get_stack_offset(),
+                            result_reg
+                        ));
+                    }
+                    UnaryOperator::SizeOf => {
+                        if let Ok(id) = operand.type_id() {
+                            let size = id.size();
+                            code.push(format!("\tmov {}, {}", size, result_reg));
+                        }
+                    }
+                    UnaryOperator::Increment => {
+                        // prefix increment
+                        // code.push(format!("\tmov {}, {}", operand_reg, result_reg));
+                        code.push(format!("\taddi {}, 1, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::Decrement => {
+                        // prefix decrement
+                        // code.push(format!("\tmov {}, {}", operand_reg, result_reg));
+                        code.push(format!("\tsubi {}, 1, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::BitwiseNot => {
+                        code.push(format!("\tnot {}, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::LogicalNot => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "Assembler/ISA does not yet support logical not"
+                        )));
+                    }
+                    _ => {
+                        return Err(CompilerError::Generic(format!(
+                            "{op} is postfix only!"
+                        )));
+                    }
+                }
+
+                self.allocator.free_temp(operand_reg);
+                Ok((result_reg, code))
+            }
+
            Expression::Call {
                func: Call { name, args },
                ..
@@ -642,69 +871,52 @@ impl CodeGenerator {
                Ok((result_reg, code))
            }

-            Expression::Unary { op, operand, .. } => {
-                let (operand_reg, operand_code) =
-                    self.generate_expression(operand, true, func_body)?;
-                code.extend(operand_code);
+            Expression::IndexAccess {
+                expr,
+                index,
+                type_id,
+            } => {
+                let (expr_reg, expr_alloc) =
+                    self.generate_expression(expr, true, func_body)?;
+                code.extend(expr_alloc);
+
+                let (index_reg, index_alloc) =
+                    self.generate_expression(index, true, func_body)?;
+                code.extend(index_alloc);

                let (result_reg, result_alloc) = self.allocator.alloc_temp()?;
                code.extend(result_alloc);

-                match op {
-                    UnaryOperator::Minus => {
-                        // Negate: result = 0 - operand
-                        code.push(format!("\tsub zero, {}, {}", operand_reg, result_reg));
-                    }
-                    UnaryOperator::Plus => {
-                        // Just move
-                        code.push(format!("\tmov {}, {}", operand_reg, result_reg));
-                    }
-                    UnaryOperator::Dereference => {
-                        code.push(format!("\tldw {}, {}", operand_reg, result_reg));
-                    }
-                    UnaryOperator::AddressOf => {
-                        // ensure the referenced variable is on the stack and return its
-                        // address.
-                        let (offset, alloc_code) =
-                            self.allocator.free_register(&operand_reg)?;
-                        code.extend(alloc_code);
-                        code.push(format!(
-                            "\taddi spr, {}, {}",
-                            offset - self.allocator.get_stack_offset(),
-                            result_reg
-                        ));
-                    }
-                    UnaryOperator::SizeOf => {
-                        if let Ok(id) = operand.type_id() {
-                            let size = id.size();
-                            code.push(format!("\tmov {}, {}", size, result_reg));
-                        }
-                    }
-                    UnaryOperator::CastAs => {} /* this should be removed once the */
-                    // semantic analyser can handle it!
-                    UnaryOperator::Increment => {
-                        // prefix increment
-                        code.push(format!("\tmov {}, {}", operand_reg, result_reg));
-                        code.push(format!("\taddi {}, {}, 1", operand_reg, operand_reg));
-                    }
-                    UnaryOperator::Decrement => {
-                        // prefix decrement
-                        code.push(format!("\tmov {}, {}", operand_reg, result_reg));
-                        code.push(format!("\tsubi {}, {}, 1", operand_reg, operand_reg));
-                    }
-                    UnaryOperator::BitwiseNot => {
-                        code.push(format!("\tnot {}, {}", operand_reg, result_reg));
-                    }
-                    UnaryOperator::LogicalNot => unimplemented!(),
-                }
+                // add the expr pointer to the index to get the final address.
+                code.push(format!("\tadd {expr_reg} {index_reg} {result_reg}"));
+                // load the value at the address.
+                code.push(format!("\tldw {result_reg} {result_reg}"));
+
+                self.allocator.free_temp(expr_reg);
+                self.allocator.free_temp(index_reg);

-                self.allocator.free_temp(operand_reg);
                Ok((result_reg, code))
            }
+            Expression::MemberAccess {
+                expr,
+                field_name,
+                type_id,
+            } => Err(CompilerError::Unimplemented(format!(
+                "Structs are not yet implemented!"
+            ))),

-            Expression::Empty => Ok((Register::Null, code)),
+            Expression::TypeCast {
+                expr,
+                target_type,
+                type_id,
+            } => {
+                let (expr_reg, expr_code) =
+                    self.generate_expression(expr, true, func_body)?;

-            _ => unimplemented!(),
+                // not sure if we actually need to do anything here.
+                // for now we just return the previous expression.
+                Ok((expr_reg, expr_code))
+            }
        }
    }

@@ -1,7 +1,8 @@
 use super::lexer::Token;
 use crate::model::{
-    BinaryOperator, Block, Call, CompilerError, ConstExpr, Declaration, Dependency,
-    Expression, Program, Statement, TypeId, UnaryOperator, Variable,
+    AssignmentOperator, BinaryOperator, Block, Call, CompilerError, ConstExpr,
+    Declaration, Dependency, Expression, Program, Statement, TypeId, UnaryOperator,
+    Variable,
 };
 use crate::{expect_tt, expect_value};
 use std::ops::{ControlFlow, FromResidual, Try};
@@ -328,7 +329,26 @@ impl Parser {
            }

            self.next()?;
-            let _ = expect_tt!(self.next()?, Assign)?;
+            let operator = match self.peek_next()? {
+                Token::Assign => AssignmentOperator::Assign,
+                Token::PlusEqual => AssignmentOperator::AddAssign,
+                Token::MinusEqual => AssignmentOperator::SubAssign,
+                Token::StarEqual => AssignmentOperator::MulAssign,
+                Token::SlashEqual => AssignmentOperator::DivAssign,
+                Token::PercentEqual => AssignmentOperator::ModAssign,
+                Token::AndEqual => AssignmentOperator::AndAssign,
+                Token::OrEqual => AssignmentOperator::OrAssign,
+                Token::XorEqual => AssignmentOperator::XorAssign,
+                Token::ShlEqual => AssignmentOperator::LeftShiftAssign,
+                Token::ShrEqual => AssignmentOperator::RightShiftAssign,
+                _ => {
+                    return ParseResult::Reject(CompilerError::UnexpectedToken(
+                        self.peek_next()?.tt().to_string(),
+                    ));
+                }
+            };
+
+            self.next()?;

            let value = self.parse_expression()?;

@@ -336,6 +356,7 @@ impl Parser {

            return ParseResult::Accept(Statement::Assign {
                varname: varname.name,
+                operator,
                value,
            });
        }
@@ -346,32 +367,132 @@ impl Parser {
    }

    fn parse_expression(&mut self) -> ParseResult<Expression, CompilerError> {
-        self.parse_comparison()
+        self.parse_logical_or()
+    }
+
+    fn parse_logical_or(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_logical_and()?;
+
+        let op = match self.peek_next()? {
+            Token::Ampersand => BinaryOperator::LogicalOr,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_logical_or()?),
+            type_id: Some(TypeId::U32),
+        })
+    }
+
+    fn parse_logical_and(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_bitwise_or()?;
+
+        let op = match self.peek_next()? {
+            Token::Ampersand => BinaryOperator::LogicalAnd,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_logical_and()?),
+            type_id: Some(TypeId::U32),
+        })
+    }
+
+    fn parse_bitwise_or(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_bitwise_xor()?;
+
+        let op = match self.peek_next()? {
+            Token::Ampersand => BinaryOperator::BitwiseOr,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_bitwise_or()?),
+            type_id: Some(TypeId::U32),
+        })
+    }
+
+    fn parse_bitwise_xor(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_bitwise_and()?;
+
+        let op = match self.peek_next()? {
+            Token::Ampersand => BinaryOperator::BitwiseXor,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_bitwise_xor()?),
+            type_id: Some(TypeId::U32),
+        })
+    }
+
+    fn parse_bitwise_and(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_comparison()?;
+
+        let op = match self.peek_next()? {
+            Token::Ampersand => BinaryOperator::BitwiseAnd,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_bitwise_and()?),
+            type_id: Some(TypeId::U32),
+        })
    }

    fn parse_comparison(&mut self) -> ParseResult<Expression, CompilerError> {
-        let mut expr = self.parse_additive()?;
+        let left = self.parse_shift()?;

-        while let Some(op) = match self.peek_next()? {
-            Token::EqualEqual => Some(BinaryOperator::Equal),
-            Token::BangEqual => Some(BinaryOperator::NotEqual),
-            Token::Less => Some(BinaryOperator::LessThan),
-            Token::Greater => Some(BinaryOperator::GreaterThan),
-            Token::LessEqual => Some(BinaryOperator::LessOrEqual),
-            Token::GreaterEqual => Some(BinaryOperator::GreaterOrEqual),
-            _ => None,
-        } {
-            self.next()?;
-            let right = Box::new(self.parse_additive()?);
-            expr = Expression::Binary {
-                op,
-                left: Box::new(expr),
-                right,
-                type_id: Some(TypeId::Bool),
-            };
-        }
+        let op = match self.peek_next()? {
+            Token::EqualEqual => BinaryOperator::Equal,
+            Token::BangEqual => BinaryOperator::NotEqual,
+            Token::Less => BinaryOperator::LessThan,
+            Token::Greater => BinaryOperator::GreaterThan,
+            Token::LessEqual => BinaryOperator::LessOrEqual,
+            Token::GreaterEqual => BinaryOperator::GreaterOrEqual,
+            _ => return ParseResult::Accept(left),
+        };

-        ParseResult::Accept(expr)
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_comparison()?),
+            type_id: Some(TypeId::Bool),
+        })
+    }
+
+    fn parse_shift(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_additive()?;
+
+        let op = match self.peek_next()? {
+            Token::LeftShift => BinaryOperator::LeftShift,
+            Token::RightShift => BinaryOperator::RightShift,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_shift()?),
+            type_id: Some(TypeId::U32),
+        })
    }

    fn parse_additive(&mut self) -> ParseResult<Expression, CompilerError> {
@@ -11,6 +11,7 @@ pub enum CompilerError {
    Generic(String),
    UnknownType,
    TypeMismatch(TypeId, TypeId),
+    Unimplemented(String),
 }

 #[derive(Debug, PartialEq, Eq, Clone)]
@@ -130,6 +131,7 @@ pub enum Statement {
    },
    Assign {
        varname: String,
+        operator: AssignmentOperator,
        value: Expression,
    },
    PtrWrite {
@@ -308,6 +310,21 @@ impl Expression {
    }
 }

+#[derive(Debug, Clone, PartialEq)]
+pub enum AssignmentOperator {
+    Assign,
+    AddAssign,
+    SubAssign,
+    MulAssign,
+    DivAssign,
+    ModAssign,
+    AndAssign,
+    OrAssign,
+    XorAssign,
+    LeftShiftAssign,
+    RightShiftAssign,
+}
+
 #[allow(unused)]
 #[derive(Debug, Clone, PartialEq)]
 pub enum BinaryOperator {
@@ -371,7 +388,6 @@ pub enum UnaryOperator {
    Minus,
    AddressOf,
    Dereference,
-    CastAs,
    BitwiseNot,
    LogicalNot,
    Increment,
@@ -388,7 +404,6 @@ impl fmt::Display for UnaryOperator {
            Self::Minus => write!(f, "-"),
            Self::Dereference => write!(f, "*"),
            Self::AddressOf => write!(f, "&"),
-            Self::CastAs => write!(f, "as"),
            Self::BitwiseNot => write!(f, "~"),
            Self::LogicalNot => write!(f, "!"),
            Self::SizeOf => write!(f, "sizeof"),