Minor list index improvements

Author: moomoohk

dpath/segments.py

@@ -4,7 +4,7 @@
 
 from dpath import options
 from dpath.exceptions import InvalidGlob, InvalidKeyName, PathNotFound
-from dpath.types import PathSegment, Creator, Hints, Glob, Path, SymmetricInt
+from dpath.types import PathSegment, Creator, Hints, Glob, Path, ListIndex
 
 
 def make_walkable(node) -> Iterator[Tuple[PathSegment, Any]]:
@@ -22,8 +22,8 @@ def make_walkable(node) -> Iterator[Tuple[PathSegment, Any]]:
     except AttributeError:
         try:
             indices = range(len(node))
-            # Convert all list indices to object so negative indexes are supported.
-            indices = map(lambda i: SymmetricInt(i, len(node)), indices)
+            # Convert all list indices to objects so negative indices are supported.
+            indices = map(lambda i: ListIndex(i, len(node)), indices)
             return zip(indices, node)
         except TypeError:
             # This can happen in cases where the node isn't leaf(node) == True,

dpath/types.py

@@ -2,32 +2,29 @@
 from typing import Union, Any, Callable, Sequence, Tuple, List, Optional, MutableMapping
 
 
-class SymmetricInt(int):
-    """Same as a normal int but mimicks the behavior of list indexes (can be compared to a negative number)."""
+class ListIndex(int):
+    """Same as a normal int but mimics the behavior of list indices (can be compared to a negative number)."""
 
-    def __new__(cls, value: int, max_value: int, *args, **kwargs):
-        if value >= max_value:
+    def __new__(cls, value: int, list_length: int, *args, **kwargs):
+        if value >= list_length:
             raise TypeError(
                 f"Tried to initiate a {cls.__name__} with a value ({value}) "
-                f"greater than the provided max value ({max_value})"
+                f"greater than the provided max value ({list_length})"
             )
 
         obj = super().__new__(cls, value)
-        obj.max_value = max_value
+        obj.list_length = list_length
 
         return obj
 
     def __eq__(self, other):
         if not isinstance(other, int):
             return False
 
-        if other >= self.max_value or other <= -self.max_value:
-            return False
-
-        return int(self) == (self.max_value + other) % self.max_value
+        return other == int(self) or self.list_length + other == int(self)
 
     def __repr__(self):
-        return f"<{self.__class__.__name__} {int(self)}%{self.max_value}>"
+        return f"<{self.__class__.__name__} {int(self)}/{self.list_length}>"
 
     def __str__(self):
         return str(int(self))