Make path instances hashable

jsonpath_ng/jsonpath.py

@@ -220,6 +220,9 @@ def __repr__(self):
     def __eq__(self, other):
         return isinstance(other, Root)
 
+    def __hash__(self):
+        return hash('$')
+
 
 class This(JSONPath):
     """
@@ -244,6 +247,9 @@ def __repr__(self):
     def __eq__(self, other):
         return isinstance(other, This)
 
+    def __hash__(self):
+        return hash('this')
+
 
 class Child(JSONPath):
     """
@@ -302,6 +308,9 @@ def __str__(self):
     def __repr__(self):
         return '%s(%r, %r)' % (self.__class__.__name__, self.left, self.right)
 
+    def __hash__(self):
+        return hash((self.left, self.right))
+
 
 class Parent(JSONPath):
     """
@@ -323,6 +332,9 @@ def __str__(self):
     def __repr__(self):
         return 'Parent()'
 
+    def __hash__(self):
+        return hash('parent')
+
 
 class Where(JSONPath):
     """
@@ -357,6 +369,9 @@ def __str__(self):
     def __eq__(self, other):
         return isinstance(other, Where) and other.left == self.left and other.right == self.right
 
+    def __hash__(self):
+        return hash((self.left, self.right))
+
 class Descendants(JSONPath):
     """
     JSONPath that matches first the left expression then any descendant
@@ -469,6 +484,9 @@ def __eq__(self, other):
     def __repr__(self):
         return '%s(%r, %r)' % (self.__class__.__name__, self.left, self.right)
 
+    def __hash__(self):
+        return hash((self.left, self.right))
+
 
 class Union(JSONPath):
     """
@@ -490,6 +508,12 @@ def is_singular(self):
     def find(self, data):
         return self.left.find(data) + self.right.find(data)
 
+    def __eq__(self, other):
+        return isinstance(other, Union) and self.left == other.left and self.right == other.right
+
+    def __hash__(self):
+        return hash((self.left, self.right))
+
 class Intersect(JSONPath):
     """
     JSONPath for bits that match *both* patterns.
@@ -511,6 +535,12 @@ def is_singular(self):
     def find(self, data):
         raise NotImplementedError()
 
+    def __eq__(self, other):
+        return isinstance(other, Intersect) and self.left == other.left and self.right == other.right
+
+    def __hash__(self):
+        return hash((self.left, self.right))
+
 
 class Fields(JSONPath):
     """
@@ -596,6 +626,9 @@ def __repr__(self):
     def __eq__(self, other):
         return isinstance(other, Fields) and tuple(self.fields) == tuple(other.fields)
 
+    def __hash__(self):
+        return hash(tuple(self.fields))
+
 
 class Index(JSONPath):
     """
@@ -662,6 +695,9 @@ def _pad_value(self, value):
             pad = self.index - len(value) + 1
             value += [{} for __ in range(pad)]
 
+    def __hash__(self):
+        return hash(self.index)
+
 
 class Slice(JSONPath):
     """
@@ -741,6 +777,9 @@ def __repr__(self):
     def __eq__(self, other):
         return isinstance(other, Slice) and other.start == self.start and self.end == other.end and other.step == self.step
 
+    def __hash__(self):
+        return hash((self.start, self.end, self.step))
+
 
 def _create_list_key(dict_):
     """

tests/test_jsonpath.py

@@ -183,6 +183,7 @@ def check_paths(self, test_cases):
 
         for string, data, target in test_cases:
             print('parse("%s").find(%s).paths =?= %s' % (string, data, target))
+            assert hash(parse(string)) == hash(parse(string))
             result = parse(string).find(data)
             if isinstance(target, list):
                 assert [str(r.full_path) for r in result] == target