some implementations

Signed-off-by: ale <ale@manalejandro.com>

src/codegen.rs

@@ -1,4 +1,4 @@
-use crate::parser::{Program, Function, Expression, Statement, Type};
+use crate::parser::{Program, Function, Expression, Statement, Type, BinaryOperator};
 use crate::targets::Target;
 use crate::error::{AleccError, Result};
 use std::collections::HashMap;
@@ -8,6 +8,7 @@ pub struct CodeGenerator {
     output: String,
     label_counter: usize,
     string_literals: HashMap<String, String>,
+    current_function_params: Vec<(String, i32)>, // (name, stack_offset)
 }
 
 impl CodeGenerator {
@@ -17,6 +18,7 @@ impl CodeGenerator {
             output: String::new(),
             label_counter: 0,
             string_literals: HashMap::new(),
+            current_function_params: Vec::new(),
         }
     }
 
@@ -49,9 +51,35 @@ impl CodeGenerator {
             self.generate_function(function)?;
         }
 
+        // Generate _start entry point
+        self.generate_start_function()?;
+
         Ok(self.output.clone())
     }
 
+    fn generate_start_function(&mut self) -> Result<()> {
+        self.emit_line("");
+        self.emit_line(".globl _start");
+        self.emit_line("_start:");
+        
+        // Set up stack and call main
+        self.emit_line("    push rbp");
+        self.emit_line("    mov rbp, rsp");
+        
+        // Reserve space for temporary operations (prevents stack corruption)
+        self.emit_line("    sub rsp, 128");
+        
+        // Call main function
+        self.emit_line("    call main");
+        
+        // Exit syscall with main's return value
+        self.emit_line("    mov rdi, rax");  // exit status = main's return value
+        self.emit_line("    mov rax, 60");   // sys_exit syscall number
+        self.emit_line("    syscall");       // invoke syscall
+        
+        Ok(())
+    }
+
     fn emit_header(&mut self) {
         match self.target {
             Target::I386 => {
@@ -59,7 +87,6 @@ impl CodeGenerator {
                 self.emit_line(".intel_syntax noprefix");
             }
             Target::Amd64 => {
-                self.emit_line(".arch x86_64");
                 self.emit_line(".intel_syntax noprefix");
             }
             Target::Arm64 => {
@@ -73,6 +100,9 @@ impl CodeGenerator {
         self.emit_line(&format!(".globl {}", function.name));
         self.emit_line(&format!("{}:", function.name));
         
+        // Set up parameter tracking
+        self.current_function_params.clear();
+        
         // Function prologue
         self.emit_function_prologue(&function.parameters)?;
         
@@ -92,28 +122,63 @@ impl CodeGenerator {
                 self.emit_line("    push ebp");
                 self.emit_line("    mov ebp, esp");
                 
-                // Reserve space for local variables (simplified)
-                let stack_space = parameters.len() * 4; // Simplified calculation
-                if stack_space > 0 {
-                    self.emit_line(&format!("    sub esp, {}", stack_space));
+                // Reserve space for parameters + 128 bytes for temporaries
+                let stack_space = parameters.len() * 4 + 128;
+                self.emit_line(&format!("    sub esp, {}", stack_space));
+                
+                // Store parameters from stack (i386 calling convention)
+                for (i, (name, _)) in parameters.iter().enumerate() {
+                    let param_offset = -(i as i32 + 1) * 4;
+                    let stack_offset = 8 + i as i32 * 4; // ebp + 8 + offset
+                    self.emit_line(&format!("    mov eax, DWORD PTR [ebp + {}]", stack_offset));
+                    self.emit_line(&format!("    mov DWORD PTR [ebp + {}], eax", param_offset));
+                    self.current_function_params.push((name.clone(), param_offset));
                 }
             }
             Target::Amd64 => {
                 self.emit_line("    push rbp");
                 self.emit_line("    mov rbp, rsp");
                 
-                let stack_space = parameters.len() * 8;
-                if stack_space > 0 {
-                    self.emit_line(&format!("    sub rsp, {}", stack_space));
+                // Reserve space for parameters + 128 bytes for temporaries
+                let stack_space = parameters.len() * 8 + 128;
+                self.emit_line(&format!("    sub rsp, {}", stack_space));
+                
+                // Store parameters from registers (x86_64 calling convention)
+                let param_registers = ["rdi", "rsi", "rdx", "rcx", "r8", "r9"];
+                for (i, (name, _)) in parameters.iter().enumerate() {
+                    let param_offset = -(i as i32 + 1) * 8;
+                    if i < param_registers.len() {
+                        // Parameter passed in register
+                        self.emit_line(&format!("    mov QWORD PTR [rbp + {}], {}", param_offset, param_registers[i]));
+                    } else {
+                        // Parameter passed on stack
+                        let stack_offset = 16 + (i - param_registers.len()) as i32 * 8;
+                        self.emit_line(&format!("    mov rax, QWORD PTR [rbp + {}]", stack_offset));
+                        self.emit_line(&format!("    mov QWORD PTR [rbp + {}], rax", param_offset));
+                    }
+                    self.current_function_params.push((name.clone(), param_offset));
                 }
             }
             Target::Arm64 => {
                 self.emit_line("    stp x29, x30, [sp, #-16]!");
                 self.emit_line("    mov x29, sp");
                 
-                let stack_space = (parameters.len() * 8 + 15) & !15; // 16-byte aligned
-                if stack_space > 0 {
-                    self.emit_line(&format!("    sub sp, sp, #{}", stack_space));
+                let stack_space = (parameters.len() * 8 + 128 + 15) & !15; // 16-byte aligned
+                self.emit_line(&format!("    sub sp, sp, #{}", stack_space));
+                
+                // Store parameters from registers (ARM64 calling convention)
+                for (i, (name, _)) in parameters.iter().enumerate() {
+                    let param_offset = -(i as i32 + 1) * 8;
+                    if i < 8 {
+                        // Parameter passed in register x0-x7
+                        self.emit_line(&format!("    str x{}, [x29, #{}]", i, param_offset));
+                    } else {
+                        // Parameter passed on stack
+                        let stack_offset = 16 + (i - 8) as i32 * 8;
+                        self.emit_line(&format!("    ldr x9, [x29, #{}]", stack_offset));
+                        self.emit_line(&format!("    str x9, [x29, #{}]", param_offset));
+                    }
+                    self.current_function_params.push((name.clone(), param_offset));
                 }
             }
         }
@@ -240,26 +305,77 @@ impl CodeGenerator {
                 }
             }
             Expression::Identifier(name) => {
-                // Load variable (simplified - assumes it's a parameter or global)
-                match self.target {
-                    Target::I386 => {
-                        self.emit_line(&format!("    mov eax, DWORD PTR [{}]", name));
+                // Check if it's a function parameter first
+                if let Some((_, offset)) = self.current_function_params.iter().find(|(param_name, _)| param_name == name) {
+                    // Load parameter from stack
+                    match self.target {
+                        Target::I386 => {
+                            self.emit_line(&format!("    mov eax, DWORD PTR [ebp + {}]", offset));
+                        }
+                        Target::Amd64 => {
+                            self.emit_line(&format!("    mov rax, QWORD PTR [rbp + {}]", offset));
+                        }
+                        Target::Arm64 => {
+                            self.emit_line(&format!("    ldr x0, [x29, #{}]", offset));
+                        }
                     }
-                    Target::Amd64 => {
-                        self.emit_line(&format!("    mov rax, QWORD PTR [{}]", name));
-                    }
-                    Target::Arm64 => {
-                        self.emit_line(&format!("    adrp x1, {}", name));
-                        self.emit_line(&format!("    add x1, x1, :lo12:{}", name));
-                        self.emit_line("    ldr x0, [x1]");
+                } else {
+                    // Load global variable
+                    match self.target {
+                        Target::I386 => {
+                            self.emit_line(&format!("    mov eax, DWORD PTR [{}]", name));
+                        }
+                        Target::Amd64 => {
+                            self.emit_line(&format!("    mov rax, QWORD PTR [{}]", name));
+                        }
+                        Target::Arm64 => {
+                            self.emit_line(&format!("    adrp x1, {}", name));
+                            self.emit_line(&format!("    add x1, x1, :lo12:{}", name));
+                            self.emit_line("    ldr x0, [x1]");
+                        }
                     }
                 }
             }
             Expression::Call { function, arguments } => {
-                // Generate arguments in reverse order
-                for (i, arg) in arguments.iter().enumerate().rev() {
-                    self.generate_expression(arg)?;
-                    self.push_argument(i)?;
+                // Generate arguments and place in calling convention registers/stack
+                match self.target {
+                    Target::I386 => {
+                        // i386: push arguments in reverse order
+                        for arg in arguments.iter().rev() {
+                            self.generate_expression(arg)?;
+                            self.emit_line("    push eax");
+                        }
+                    }
+                    Target::Amd64 => {
+                        // x86_64: first 6 args in registers, rest on stack
+                        let param_registers = ["rdi", "rsi", "rdx", "rcx", "r8", "r9"];
+                        
+                        // Generate arguments and store in registers/stack
+                        for (i, arg) in arguments.iter().enumerate() {
+                            self.generate_expression(arg)?;
+                            if i < param_registers.len() {
+                                // Move to parameter register
+                                self.emit_line(&format!("    mov {}, rax", param_registers[i]));
+                            } else {
+                                // Push to stack (reverse order for stack args)
+                                self.emit_line("    push rax");
+                            }
+                        }
+                    }
+                    Target::Arm64 => {
+                        // ARM64: first 8 args in x0-x7, rest on stack
+                        for (i, arg) in arguments.iter().enumerate() {
+                            self.generate_expression(arg)?;
+                            if i < 8 {
+                                if i > 0 {
+                                    self.emit_line(&format!("    mov x{}, x0", i));
+                                }
+                                // x0 already has the result for first argument
+                            } else {
+                                self.emit_line("    str x0, [sp, #-16]!");
+                            }
+                        }
+                    }
                 }
                 
                 if let Expression::Identifier(func_name) = function.as_ref() {
@@ -270,18 +386,128 @@ impl CodeGenerator {
                     });
                 }
                 
-                // Clean up stack
-                let stack_cleanup = arguments.len() * self.target.pointer_size();
-                if stack_cleanup > 0 {
-                    match self.target {
-                        Target::I386 => {
+                // Clean up stack for arguments that were pushed
+                match self.target {
+                    Target::I386 => {
+                        let stack_cleanup = arguments.len() * 4;
+                        if stack_cleanup > 0 {
                             self.emit_line(&format!("    add esp, {}", stack_cleanup));
                         }
-                        Target::Amd64 => {
-                            // Arguments passed in registers, no cleanup needed
+                    }
+                    Target::Amd64 => {
+                        // Clean up stack arguments (if any)
+                        let stack_args = if arguments.len() > 6 { arguments.len() - 6 } else { 0 };
+                        if stack_args > 0 {
+                            self.emit_line(&format!("    add rsp, {}", stack_args * 8));
                         }
-                        Target::Arm64 => {
-                            // Arguments passed in registers, no cleanup needed
+                    }
+                    Target::Arm64 => {
+                        // Clean up stack arguments (if any)
+                        let stack_args = if arguments.len() > 8 { arguments.len() - 8 } else { 0 };
+                        if stack_args > 0 {
+                            self.emit_line(&format!("    add sp, sp, #{}", stack_args * 16));
+                        }
+                    }
+                }
+            }
+            Expression::Binary { left, operator, right } => {
+                // Generate binary operations
+                // First generate right operand and save it
+                self.generate_expression(right)?;
+                match self.target {
+                    Target::I386 => {
+                        self.emit_line("    push eax");  // Save right operand
+                    }
+                    Target::Amd64 => {
+                        self.emit_line("    push rax");  // Save right operand
+                    }
+                    Target::Arm64 => {
+                        self.emit_line("    str x0, [sp, #-16]!");  // Save right operand
+                    }
+                }
+                
+                // Generate left operand
+                self.generate_expression(left)?;
+                
+                // Pop right operand and perform operation
+                match self.target {
+                    Target::I386 => {
+                        self.emit_line("    pop ebx");   // Right operand in ebx
+                        match operator {
+                            BinaryOperator::Add => self.emit_line("    add eax, ebx"),
+                            BinaryOperator::Subtract => self.emit_line("    sub eax, ebx"),
+                            BinaryOperator::Multiply => self.emit_line("    imul eax, ebx"),
+                            BinaryOperator::Divide => {
+                                self.emit_line("    cdq");  // Sign extend eax to edx:eax
+                                self.emit_line("    idiv ebx");
+                            }
+                            _ => {
+                                return Err(AleccError::CodegenError {
+                                    message: format!("Binary operator {:?} not implemented for i386", operator),
+                                });
+                            }
+                        }
+                    }
+                    Target::Amd64 => {
+                        self.emit_line("    pop rbx");   // Right operand in rbx
+                        match operator {
+                            BinaryOperator::Add => self.emit_line("    add rax, rbx"),
+                            BinaryOperator::Subtract => self.emit_line("    sub rax, rbx"),
+                            BinaryOperator::Multiply => self.emit_line("    imul rax, rbx"),
+                            BinaryOperator::Divide => {
+                                self.emit_line("    cqo");  // Sign extend rax to rdx:rax
+                                self.emit_line("    idiv rbx");
+                            }
+                            // Comparison operators
+                            BinaryOperator::Equal => {
+                                self.emit_line("    cmp rax, rbx");
+                                self.emit_line("    sete al");
+                                self.emit_line("    movzx rax, al");
+                            }
+                            BinaryOperator::NotEqual => {
+                                self.emit_line("    cmp rax, rbx");
+                                self.emit_line("    setne al");
+                                self.emit_line("    movzx rax, al");
+                            }
+                            BinaryOperator::Less => {
+                                self.emit_line("    cmp rax, rbx");
+                                self.emit_line("    setl al");
+                                self.emit_line("    movzx rax, al");
+                            }
+                            BinaryOperator::Greater => {
+                                self.emit_line("    cmp rax, rbx");
+                                self.emit_line("    setg al");
+                                self.emit_line("    movzx rax, al");
+                            }
+                            BinaryOperator::LessEqual => {
+                                self.emit_line("    cmp rax, rbx");
+                                self.emit_line("    setle al");
+                                self.emit_line("    movzx rax, al");
+                            }
+                            BinaryOperator::GreaterEqual => {
+                                self.emit_line("    cmp rax, rbx");
+                                self.emit_line("    setge al");
+                                self.emit_line("    movzx rax, al");
+                            }
+                            _ => {
+                                return Err(AleccError::CodegenError {
+                                    message: format!("Binary operator {:?} not implemented for amd64", operator),
+                                });
+                            }
+                        }
+                    }
+                    Target::Arm64 => {
+                        self.emit_line("    ldr x1, [sp], #16");  // Right operand in x1
+                        match operator {
+                            BinaryOperator::Add => self.emit_line("    add x0, x0, x1"),
+                            BinaryOperator::Subtract => self.emit_line("    sub x0, x0, x1"),
+                            BinaryOperator::Multiply => self.emit_line("    mul x0, x0, x1"),
+                            BinaryOperator::Divide => self.emit_line("    sdiv x0, x0, x1"),
+                            _ => {
+                                return Err(AleccError::CodegenError {
+                                    message: format!("Binary operator {:?} not implemented for arm64", operator),
+                                });
+                            }
                         }
                     }
                 }

src/linker.rs

@@ -210,40 +210,20 @@ impl Linker {
             command.push(lib.clone());
         }
 
-        // Standard libraries
+        // Standard libraries - skip for now to avoid conflicts
+        // Our programs use custom runtime with syscalls
+        /*
         if !self.static_link {
             command.push("-lc".to_string());
         }
+        */
 
         Ok(command)
     }
 
     fn add_standard_startup_files(&self, command: &mut Vec<String>) -> Result<()> {
-        let lib_path = match self.target {
-            Target::I386 => "/usr/lib/i386-linux-gnu",
-            Target::Amd64 => "/usr/lib/x86_64-linux-gnu",
-            Target::Arm64 => "/usr/lib/aarch64-linux-gnu",
-        };
-
-        // Add crt1.o, crti.o, crtbegin.o
-        let startup_files = if self.pie {
-            vec!["Scrt1.o", "crti.o"]
-        } else {
-            vec!["crt1.o", "crti.o"]
-        };
-
-        for file in startup_files {
-            command.push(format!("{}/{}", lib_path, file));
-        }
-
-        // Add GCC's crtbegin.o
-        let gcc_lib = self.get_gcc_lib_path()?;
-        if self.shared {
-            command.push(format!("{}/crtbeginS.o", gcc_lib));
-        } else {
-            command.push(format!("{}/crtbegin.o", gcc_lib));
-        }
-
+        // Skip startup files when we have our own _start
+        // This prevents conflicts with our custom _start implementation
         Ok(())
     }
 

src/parser.rs

@@ -169,7 +169,9 @@ pub struct Parser {
 
 impl Parser {
     pub fn new(tokens: Vec<Token>) -> Self {
-        Self { tokens, current: 0 }
+        let mut parser = Self { tokens, current: 0 };
+        parser.skip_newlines(); // Skip initial newlines
+        parser
     }
 
     pub fn parse(&mut self) -> Result<Program> {
@@ -384,9 +386,24 @@ impl Parser {
         if !self.is_at_end() {
             self.current += 1;
         }
+        self.skip_newlines();
         self.previous()
     }
 
+    fn skip_newlines(&mut self) {
+        while !self.is_at_end() {
+            if let Ok(token) = self.current_token() {
+                if token.token_type == TokenType::Newline {
+                    self.current += 1;
+                } else {
+                    break;
+                }
+            } else {
+                break;
+            }
+        }
+    }
+
     fn previous(&self) -> Result<&Token> {
         self.tokens.get(self.current - 1).ok_or_else(|| AleccError::ParseError {
             line: 0,
@@ -426,6 +443,16 @@ impl Parser {
         }
     }
 
+    fn match_tokens(&mut self, token_types: &[TokenType]) -> bool {
+        for token_type in token_types {
+            if self.check(token_type) {
+                self.advance().unwrap();
+                return true;
+            }
+        }
+        false
+    }
+
     fn consume(&mut self, token_type: &TokenType, message: &str) -> Result<&Token> {
         if self.check(token_type) {
             self.advance()
@@ -495,6 +522,7 @@ impl Parser {
         self.consume(&TokenType::RightParen, "Expected ')' after parameters")?;
         
         let body = if self.check(&TokenType::LeftBrace) {
+            self.advance()?; // Consume the LeftBrace
             self.parse_block_statement()?
         } else {
             self.consume(&TokenType::Semicolon, "Expected ';' after function declaration")?;
@@ -535,8 +563,7 @@ impl Parser {
     }
 
     fn parse_block_statement(&mut self) -> Result<Statement> {
-        self.consume(&TokenType::LeftBrace, "Expected '{'")?;
-        
+        // Note: LeftBrace was already consumed by match_token in parse_statement
         let mut statements = Vec::new();
         while !self.check(&TokenType::RightBrace) && !self.is_at_end() {
             statements.push(self.parse_statement()?);
@@ -547,7 +574,7 @@ impl Parser {
     }
 
     fn parse_statement(&mut self) -> Result<Statement> {
-        // Simplified statement parsing
+        // Try to parse different types of statements
         if self.match_token(&TokenType::Return) {
             let expr = if !self.check(&TokenType::Semicolon) {
                 Some(self.parse_expression()?)
@@ -556,25 +583,306 @@ impl Parser {
             };
             self.consume(&TokenType::Semicolon, "Expected ';' after return")?;
             Ok(Statement::Return(expr))
+        } else if self.match_token(&TokenType::If) {
+            self.parse_if_statement()
+        } else if self.match_token(&TokenType::While) {
+            self.parse_while_statement()
+        } else if self.match_token(&TokenType::For) {
+            self.parse_for_statement()
+        } else if self.match_token(&TokenType::LeftBrace) {
+            self.parse_block_statement()
+        } else if self.is_type(&self.current_token()?.token_type) {
+            // Variable declaration - convert to Statement format
+            let var_type = self.parse_type()?;
+            let name = if let TokenType::Identifier(name) = &self.advance()?.token_type {
+                name.clone()
+            } else {
+                return Err(AleccError::ParseError {
+                    line: self.current_token()?.line,
+                    column: self.current_token()?.column,
+                    message: "Expected variable name".to_string(),
+                });
+            };
+
+            let initializer = if self.match_token(&TokenType::Assign) {
+                Some(self.parse_expression()?)
+            } else {
+                None
+            };
+
+            self.consume(&TokenType::Semicolon, "Expected ';' after variable declaration")?;
+            
+            Ok(Statement::Declaration {
+                name,
+                var_type,
+                initializer,
+            })
         } else {
+            // Expression statement
             let expr = self.parse_expression()?;
             self.consume(&TokenType::Semicolon, "Expected ';' after expression")?;
             Ok(Statement::Expression(expr))
         }
     }
 
+    fn parse_if_statement(&mut self) -> Result<Statement> {
+        self.consume(&TokenType::LeftParen, "Expected '(' after 'if'")?;
+        let condition = self.parse_expression()?;
+        self.consume(&TokenType::RightParen, "Expected ')' after if condition")?;
+        
+        let then_stmt = Box::new(self.parse_statement()?);
+        let else_stmt = if self.match_token(&TokenType::Else) {
+            Some(Box::new(self.parse_statement()?))
+        } else {
+            None
+        };
+        
+        Ok(Statement::If {
+            condition,
+            then_stmt,
+            else_stmt,
+        })
+    }
+
+    fn parse_while_statement(&mut self) -> Result<Statement> {
+        self.consume(&TokenType::LeftParen, "Expected '(' after 'while'")?;
+        let condition = self.parse_expression()?;
+        self.consume(&TokenType::RightParen, "Expected ')' after while condition")?;
+        let body = Box::new(self.parse_statement()?);
+        
+        Ok(Statement::While { condition, body })
+    }
+
+    fn parse_for_statement(&mut self) -> Result<Statement> {
+        self.consume(&TokenType::LeftParen, "Expected '(' after 'for'")?;
+        
+        let init = if self.check(&TokenType::Semicolon) {
+            None
+        } else {
+            Some(Box::new(self.parse_statement()?))
+        };
+        
+        if init.is_none() {
+            self.advance()?; // consume semicolon
+        }
+        
+        let condition = if self.check(&TokenType::Semicolon) {
+            None
+        } else {
+            Some(self.parse_expression()?)
+        };
+        self.consume(&TokenType::Semicolon, "Expected ';' after for condition")?;
+        
+        let increment = if self.check(&TokenType::RightParen) {
+            None
+        } else {
+            Some(self.parse_expression()?)
+        };
+        self.consume(&TokenType::RightParen, "Expected ')' after for clauses")?;
+        
+        let body = Box::new(self.parse_statement()?);
+        
+        Ok(Statement::For {
+            init,
+            condition,
+            increment,
+            body,
+        })
+    }
+
+    fn is_type(&self, token_type: &TokenType) -> bool {
+        matches!(token_type, 
+            TokenType::Int | TokenType::Float | TokenType::Double | 
+            TokenType::Char | TokenType::Void | TokenType::Short | 
+            TokenType::Long | TokenType::Signed | TokenType::Unsigned)
+    }
+
     fn parse_expression(&mut self) -> Result<Expression> {
-        // Simplified expression parsing - just literals and identifiers for now
-        match &self.advance()?.token_type {
+        self.parse_logical_or()
+    }
+
+    fn parse_logical_or(&mut self) -> Result<Expression> {
+        let mut expr = self.parse_logical_and()?;
+        
+        while self.match_token(&TokenType::LogicalOr) {
+            let operator = BinaryOperator::LogicalOr;
+            let right = self.parse_logical_and()?;
+            expr = Expression::Binary {
+                left: Box::new(expr),
+                operator,
+                right: Box::new(right),
+            };
+        }
+        
+        Ok(expr)
+    }
+
+    fn parse_logical_and(&mut self) -> Result<Expression> {
+        let mut expr = self.parse_equality()?;
+        
+        while self.match_token(&TokenType::LogicalAnd) {
+            let operator = BinaryOperator::LogicalAnd;
+            let right = self.parse_equality()?;
+            expr = Expression::Binary {
+                left: Box::new(expr),
+                operator,
+                right: Box::new(right),
+            };
+        }
+        
+        Ok(expr)
+    }
+
+    fn parse_equality(&mut self) -> Result<Expression> {
+        let mut expr = self.parse_comparison()?;
+        
+        while self.match_tokens(&[TokenType::Equal, TokenType::NotEqual]) {
+            let operator = match self.previous()?.token_type {
+                TokenType::Equal => BinaryOperator::Equal,
+                TokenType::NotEqual => BinaryOperator::NotEqual,
+                _ => unreachable!(),
+            };
+            let right = self.parse_comparison()?;
+            expr = Expression::Binary {
+                left: Box::new(expr),
+                operator,
+                right: Box::new(right),
+            };
+        }
+        
+        Ok(expr)
+    }
+
+    fn parse_comparison(&mut self) -> Result<Expression> {
+        let mut expr = self.parse_term()?;
+        
+        while self.match_tokens(&[TokenType::Greater, TokenType::GreaterEqual, 
+                                  TokenType::Less, TokenType::LessEqual]) {
+            let operator = match self.previous()?.token_type {
+                TokenType::Greater => BinaryOperator::Greater,
+                TokenType::GreaterEqual => BinaryOperator::GreaterEqual,
+                TokenType::Less => BinaryOperator::Less,
+                TokenType::LessEqual => BinaryOperator::LessEqual,
+                _ => unreachable!(),
+            };
+            let right = self.parse_term()?;
+            expr = Expression::Binary {
+                left: Box::new(expr),
+                operator,
+                right: Box::new(right),
+            };
+        }
+        
+        Ok(expr)
+    }
+
+    fn parse_term(&mut self) -> Result<Expression> {
+        let mut expr = self.parse_factor()?;
+        
+        while self.match_tokens(&[TokenType::Minus, TokenType::Plus]) {
+            let operator = match self.previous()?.token_type {
+                TokenType::Minus => BinaryOperator::Subtract,
+                TokenType::Plus => BinaryOperator::Add,
+                _ => unreachable!(),
+            };
+            let right = self.parse_factor()?;
+            expr = Expression::Binary {
+                left: Box::new(expr),
+                operator,
+                right: Box::new(right),
+            };
+        }
+        
+        Ok(expr)
+    }
+
+    fn parse_factor(&mut self) -> Result<Expression> {
+        let mut expr = self.parse_unary()?;
+        
+        while self.match_tokens(&[TokenType::Divide, TokenType::Multiply, TokenType::Modulo]) {
+            let operator = match self.previous()?.token_type {
+                TokenType::Divide => BinaryOperator::Divide,
+                TokenType::Multiply => BinaryOperator::Multiply,
+                TokenType::Modulo => BinaryOperator::Modulo,
+                _ => unreachable!(),
+            };
+            let right = self.parse_unary()?;
+            expr = Expression::Binary {
+                left: Box::new(expr),
+                operator,
+                right: Box::new(right),
+            };
+        }
+        
+        Ok(expr)
+    }
+
+    fn parse_unary(&mut self) -> Result<Expression> {
+        if self.match_tokens(&[TokenType::LogicalNot, TokenType::Minus, TokenType::Plus]) {
+            let operator = match self.previous()?.token_type {
+                TokenType::LogicalNot => UnaryOperator::LogicalNot,
+                TokenType::Minus => UnaryOperator::Minus,
+                TokenType::Plus => UnaryOperator::Plus,
+                _ => unreachable!(),
+            };
+            let right = self.parse_unary()?;
+            return Ok(Expression::Unary {
+                operator,
+                operand: Box::new(right),
+            });
+        }
+        
+        self.parse_call()
+    }
+
+    fn parse_call(&mut self) -> Result<Expression> {
+        let mut expr = self.parse_primary()?;
+        
+        while self.match_token(&TokenType::LeftParen) {
+            expr = self.finish_call(expr)?;
+        }
+        
+        Ok(expr)
+    }
+
+    fn finish_call(&mut self, callee: Expression) -> Result<Expression> {
+        let mut arguments = Vec::new();
+        
+        if !self.check(&TokenType::RightParen) {
+            loop {
+                arguments.push(self.parse_expression()?);
+                if !self.match_token(&TokenType::Comma) {
+                    break;
+                }
+            }
+        }
+        
+        self.consume(&TokenType::RightParen, "Expected ')' after arguments")?;
+        
+        Ok(Expression::Call {
+            function: Box::new(callee),
+            arguments,
+        })
+    }
+
+    fn parse_primary(&mut self) -> Result<Expression> {
+        if self.match_token(&TokenType::LeftParen) {
+            let expr = self.parse_expression()?;
+            self.consume(&TokenType::RightParen, "Expected ')' after expression")?;
+            return Ok(expr);
+        }
+        
+        let token = self.advance()?;
+        match &token.token_type {
             TokenType::IntegerLiteral(value) => Ok(Expression::IntegerLiteral(*value)),
             TokenType::FloatLiteral(value) => Ok(Expression::FloatLiteral(*value)),
             TokenType::StringLiteral(value) => Ok(Expression::StringLiteral(value.clone())),
             TokenType::CharLiteral(value) => Ok(Expression::CharLiteral(*value)),
             TokenType::Identifier(name) => Ok(Expression::Identifier(name.clone())),
             _ => Err(AleccError::ParseError {
-                line: self.current_token()?.line,
-                column: self.current_token()?.column,
-                message: "Expected expression".to_string(),
+                line: token.line,
+                column: token.column,
+                message: format!("Expected expression, found {:?}", token.token_type),
             }),
         }
     }