5 files changed, 22 insertions, 9 deletions
diff --git a/include/ast.h b/include/ast.h
index 0c34d0b..c45d4aa 100644
--- a/include/ast.h
+++ b/include/ast.h
@@ -132,6 +132,12 @@ struct Scope {
     FunctionSignature *function_signature; /* Borrowed from FunctionDecl. Only used if the scope belongs to FunctionDecl */
 };
 
+typedef enum {
+    VARIABLE_TYPE_FLAG_NONE      = 0,
+    VARIABLE_TYPE_FLAG_OPTIONAL  = 1 << 0,
+    VARIABLE_TYPE_FLAG_BORROW    = 1 << 1
+} VariableTypeFlag;
+
 typedef struct {
     enum {
         VARIABLE_TYPE_NONE,
@@ -143,6 +149,7 @@ typedef struct {
         Variable *variable;
         FunctionSignature *signature;
     } value;
+    VariableTypeFlag variable_type_flags;
 } VariableType;
 
 struct FileScopeReference {
diff --git a/include/bytecode/bytecode.h b/include/bytecode/bytecode.h
index 8f786a2..23bc4cf 100644
--- a/include/bytecode/bytecode.h
+++ b/include/bytecode/bytecode.h
@@ -77,7 +77,8 @@ typedef enum {
 
 typedef enum {
     FUNC_FLAG_NONE       = 0,
-    FUNC_FLAG_EXPORTED   = 1 << 0
+    FUNC_FLAG_EXPORTED   = 1 << 0,
+    FUNC_FLAG_VARARGS    = 1 << 1
 } amal_func_flag;
 
 typedef u8 AmalOpcodeType;
@@ -110,10 +111,13 @@ typedef struct {
 #pragma pack(push, 1)
 typedef struct {
     u8 num_params;
+    u8 num_return_types;
+    u8 name_len;
+    u8 flags;
+
     u32 params_num_pointers;
     u32 params_fixed_size;
 
-    u8 num_return_types;
     u32 return_types_num_pointers;
     u32 return_types_fixed_size;
 } BytecodeHeaderExternFunction;
diff --git a/include/compiler.h b/include/compiler.h
index f6599a1..164cf4e 100644
--- a/include/compiler.h
+++ b/include/compiler.h
@@ -15,7 +15,7 @@
 #define AMAL_COMPILER_ERR -1
 #define AMAL_COMPILER_WORK_FAIL_ABORT -2
 
-#define NUM_ARITHMETIC_TYPES 10
+#define NUM_ARITHMETIC_TYPES 14
 
 typedef struct {
     LhsExpr lhs_expr;
@@ -42,6 +42,7 @@ typedef struct {
     amal_default_type *c_int;
     amal_default_type *c_long;
     amal_default_type *c_void;
+    amal_default_type *c_varargs;
 
     amal_default_type *str;
 
diff --git a/include/program.h b/include/program.h
index aa318d9..dc65cb7 100644
--- a/include/program.h
+++ b/include/program.h
@@ -38,13 +38,11 @@
 #define AMAL_PROGRAM_INVALID_IMPORTS -26
 #define AMAL_PROGRAM_SECTION_ERROR -27
 
-#define AMAL_PROGRAM_ARGS_SIZE_VARARGS -1
-
 #define AMAL_PROGRAM_MAX_RETURN_VALUES 128
 
 typedef struct {
     void *func;
-    int args_byte_size; /* -1 if varargs (AMAL_PROGRAM_ARGS_SIZE_VARARGS) */
+    u32 args_byte_size;
 } ProgramExternFunc;
 
 typedef struct {
@@ -81,9 +79,10 @@ void amal_program_deinit(amal_program *self);
 
 /*
     returns @AMAL_PROGRAM_EXTERN_FUNC_ALREADY_EXISTS if a function with the name @name already exists
-    in the program
+    in the program.
+    If the function has a vararg parameter, then @args_byte_size should be the minimum parameters size excluding the varargs.
 */
-CHECK_RESULT int amal_program_register_extern_func(amal_program *self, BufferView name, void *func_ptr, int args_byte_size);
+CHECK_RESULT int amal_program_register_extern_func(amal_program *self, BufferView name, void *func_ptr, u32 args_byte_size);
 
 CHECK_RESULT int amal_program_append_bytecode(amal_program *self, Bytecode *bytecode);
 CHECK_RESULT int amal_program_run(amal_program *self);
diff --git a/include/tokenizer.h b/include/tokenizer.h
index b6b401b..53351a4 100644
--- a/include/tokenizer.h
+++ b/include/tokenizer.h
@@ -40,7 +40,9 @@ typedef enum {
     TOK_WHILE,
     TOK_EXTERN,
     TOK_EXPORT,
-    TOK_RETURN
+    TOK_RETURN,
+    TOK_QUESTION_MARK,
+    TOK_C_VARARGS
 } Token;
 
 struct Tokenizer {