fix(bytes): make bytes object iterable - fixes #450

include/pocketpy/interpreter/vm.h

@@ -133,6 +133,7 @@ void pk_number__register();
 py_Type pk_str__register();
 py_Type pk_str_iterator__register();
 py_Type pk_bytes__register();
+py_Type pk_bytes_iterator__register();
 py_Type pk_dict__register();
 py_Type pk_dict_items__register();
 py_Type pk_list__register();

include/pocketpy/pocketpy.h

@@ -840,6 +840,7 @@ enum py_PredefinedType {
     tp_BaseException,
     tp_Exception,
     tp_bytes,
+    tp_bytes_iterator,
     tp_namedict,
     tp_locals,
     tp_code,

src/bindings/py_str.c

@@ -674,6 +674,33 @@ py_Type pk_str_iterator__register() {
     return type;
 }
 
+static bool bytes__iter__(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(1);
+    int* ud = py_newobject(py_retval(), tp_bytes_iterator, 1, sizeof(int));
+    *ud = 0;
+    py_setslot(py_retval(), 0, argv);  // keep a reference to the bytes object
+    return true;
+}
+
+bool bytes_iterator__next__(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(1);
+    int* ud = py_touserdata(&argv[0]);
+    int size;
+    unsigned char* data = py_tobytes(py_getslot(argv, 0), &size);
+    if(*ud == size) return StopIteration();
+    py_newint(py_retval(), data[*ud]);  // return the byte value as an integer (0-255)
+    *ud += 1;
+    return true;
+}
+
+py_Type pk_bytes_iterator__register() {
+    py_Type type = pk_newtype("bytes_iterator", tp_object, NULL, NULL, false, true);
+
+    py_bindmagic(type, __iter__, pk_wrapper__self);
+    py_bindmagic(type, __next__, bytes_iterator__next__);
+    return type;
+}
+
 static bool bytes__new__(int argc, py_Ref argv) {
     if(argc == 1) {
         py_newbytes(py_retval(), 0);
@@ -808,6 +835,7 @@ py_Type pk_bytes__register() {
     py_bindmagic(tp_bytes, __add__, bytes__add__);
     py_bindmagic(tp_bytes, __hash__, bytes__hash__);
     py_bindmagic(tp_bytes, __len__, bytes__len__);
+    py_bindmagic(tp_bytes, __iter__, bytes__iter__);
 
     py_bindmethod(tp_bytes, "decode", bytes_decode);
     return type;

src/interpreter/vm.c

@@ -156,6 +156,7 @@ void VM__ctor(VM* self) {
     validate(tp_BaseException, pk_BaseException__register());
     validate(tp_Exception, pk_Exception__register());
     validate(tp_bytes, pk_bytes__register());
+    validate(tp_bytes_iterator, pk_bytes_iterator__register());
     validate(tp_namedict, pk_namedict__register());
     validate(tp_locals, pk_newtype("locals", tp_object, NULL, NULL, false, true));
     validate(tp_code, pk_code__register());

test_bytes_iter.py

@@ -0,0 +1,76 @@
+#!/usr/bin/env python3
+# Test script for bytes iteration fix (issue #450)
+
+print("Testing bytes iteration...")
+print()
+
+# Test 1: Basic bytes creation and representation
+text = "Hello"
+byte_data = text.encode()
+print("Test 1: Basic bytes creation and representation")
+print(f"Text: {text}")
+print(f"Bytes: {byte_data}")
+print()
+
+# Test 2: list(bytes)
+print("Test 2: list(byte_data):")
+try:
+    result = list(byte_data)
+    print(f"Result: {result}")
+    expected = [72, 101, 108, 108, 111]
+    assert result == expected, f"Expected {expected}, got {result}"
+    print("✓ PASS")
+except Exception as e:
+    print(f"✗ FAIL: {e}")
+print()
+
+# Test 3: for loop iteration
+print("Test 3: for loop iteration")
+try:
+    result = []
+    for x in byte_data:
+        result.append(x)
+    print(f"Result: {result}")
+    expected = [72, 101, 108, 108, 111]
+    assert result == expected, f"Expected {expected}, got {result}"
+    print("✓ PASS")
+except Exception as e:
+    print(f"✗ FAIL: {e}")
+print()
+
+# Test 4: bytes indexing (should still work)
+print("Test 4: bytes indexing")
+try:
+    result = byte_data[0]
+    print(f"byte_data[0] = {result}")
+    assert result == 72, f"Expected 72, got {result}"
+    print("✓ PASS")
+except Exception as e:
+    print(f"✗ FAIL: {e}")
+print()
+
+# Test 5: len(bytes)
+print("Test 5: len(byte_data)")
+try:
+    result = len(byte_data)
+    print(f"len(byte_data) = {result}")
+    assert result == 5, f"Expected 5, got {result}"
+    print("✓ PASS")
+except Exception as e:
+    print(f"✗ FAIL: {e}")
+print()
+
+# Test 6: bytes slicing
+print("Test 6: bytes slicing")
+try:
+    result = byte_data[1:3]
+    result_list = list(result)
+    print(f"list(byte_data[1:3]) = {result_list}")
+    expected = [101, 108]
+    assert result_list == expected, f"Expected {expected}, got {result_list}"
+    print("✓ PASS")
+except Exception as e:
+    print(f"✗ FAIL: {e}")
+print()
+
+print("All tests completed!")