small variable-name change

local Variable is_python36 changed to is_fixed_wordsize_bytecode. This
clarifies *why* this distinction is importants. Also, add more annotations.

Author: rocky

xdis/bytecode.py

@@ -92,7 +92,7 @@ def get_const_info(const_index, const_list):
 _get_const_info = get_const_info
 
 
-def get_name_info(name_index, name_list):
+def get_name_info(name_index: int, name_list) -> tuple:
     """Helper to get optional details about named references
 
     Returns the dereferenced name as both value and repr if the name
@@ -189,7 +189,7 @@ def _parse_varint(iterator: Iterator[int]) -> int:
 )
 
 
-def parse_exception_table(exception_table: bytes):
+def parse_exception_table(exception_table: bytes) -> list:
     iterator = iter(exception_table)
     entries = []
     try:
@@ -248,15 +248,17 @@ def get_logical_instruction_at_offset(
         # PERFORMANCE FIX: Only add exception labels if we're building labels ourselves
         # When called from get_instructions_bytes, labels already includes exception targets
         if exception_entries is not None:
-            for start, end, target, _, _ in exception_entries:
+            for _start, _end, target, _, _ in exception_entries:
                 if target not in labels:
                     labels.append(target)
 
     # label_maps = get_jump_target_maps(bytecode, opc)
 
     # FIXME: We really need to distinguish 3.6.0a1 from 3.6.a3.
-    # See below FIXME
-    python_36 = True if opc.python_version >= (3, 6) else False
+    # See below FIXME.
+    # Python 3.6 starts fixed-length bytecode of 2 bytes per instruction.
+    # Before that and initially, bytecode was either 1 or 3 bytes.
+    is_fixed_wordsize_bytecode = True if opc.python_version >= (3, 6) else False
 
     starts_line = None
 
@@ -295,7 +297,7 @@ def get_logical_instruction_at_offset(
         argrepr = ""
         has_arg = op_has_argument(op, opc)
         if has_arg:
-            if python_36:
+            if is_fixed_wordsize_bytecode:
                 arg = code2num(bytecode, i) | extended_arg
                 extended_arg = (arg << 8) if opname == "EXTENDED_ARG" else 0
                 # FIXME: Python 3.6.0a1 is 2, for 3.6.a3 we have 1
@@ -392,15 +394,18 @@ def get_logical_instruction_at_offset(
                 argrepr = argval
             elif op in opc.NARGS_OPS:
                 opname = opname
-                if python_36 and opname in ("CALL_FUNCTION", "CALL_FUNCTION_EX"):
+                if is_fixed_wordsize_bytecode and opname in (
+                    "CALL_FUNCTION",
+                    "CALL_FUNCTION_EX",
+                ):
                     if opname == "CALL_FUNCTION":
                         argrepr = format_CALL_FUNCTION(code2num(bytecode, i - 1))
                     else:
                         assert opname == "CALL_FUNCTION_EX"
                         argrepr = format_CALL_FUNCTION_EX(code2num(bytecode, i - 1))
                 else:
                     if not (
-                        python_36
+                        is_fixed_wordsize_bytecode
                         or opname in ("RAISE_VARARGS", "DUP_TOPX", "MAKE_FUNCTION")
                     ):
                         argrepr = "%d positional, %d named" % (
@@ -410,7 +415,7 @@ def get_logical_instruction_at_offset(
             if hasattr(opc, "opcode_arg_fmt") and opname in opc.opcode_arg_fmt:
                 argrepr = opc.opcode_arg_fmt[opname](arg)
         else:
-            if python_36:
+            if is_fixed_wordsize_bytecode:
                 i += 1
             if hasattr(opc, "opcode_arg_fmt") and opname in opc.opcode_arg_fmt:
                 argrepr = opc.opcode_arg_fmt[opname](arg)