From 93f8c04ce620a43ea5bcd5abb635f8efa029086e Mon Sep 17 00:00:00 2001
From: Alter Ego <0x7c48@gmail.com>
Date: Thu, 22 Feb 2024 20:27:23 +0100
Subject: [PATCH] Python BaseUniqueSortedEnum

---
 README.md       | 79 +++++++++++++++++++++++++++++++++++++++++++++++++
 python/enums.py | 71 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 150 insertions(+)
 create mode 100644 python/enums.py

diff --git a/README.md b/README.md
index 4ce3b00..a981c1b 100644
--- a/README.md
+++ b/README.md
@@ -2145,6 +2145,85 @@ and [Helping Modular Humanize AI Through Brand](https://www.metalab.com/blog/hel
 * [Apache TVM](https://tvm.apache.org)
 
 
+## Python hints
+
+Python problem with PostgreSQL Enum type.
+We need names and values as strings, and we need to maintain their order.
+
+```Python
+import enum
+from functools import total_ordering
+
+
+@total_ordering
+@enum.unique
+class BaseUniqueSortedEnum(enum.Enum):
+    """Base unique enum class with ordering."""
+
+    def __new__(cls, *args, **kwargs):
+        obj = object.__new__(cls)
+        obj.index = len(cls.__members__) + 1
+        return obj
+
+    def __hash__(self) -> int:
+        return hash(
+          f"{self.__module__}_{self.__class__.__name__}_{self.name}_{self.value}"
+        )
+
+    def __eq__(self, other) -> bool:
+        self._check_type(other)
+        return super().__eq__(other)
+
+    def __lt__(self, other) -> bool:
+        self._check_type(other)
+        return self.index < other.index
+
+    def _check_type(self, other) -> None:
+        if type(self) != type(other):
+            raise TypeError(f"Different types of Enum: {self} != {other}")
+
+
+class Dog(BaseUniqueSortedEnum):
+    BLOODHOUND = "BLOODHOUND"
+    WEIMARANER = "WEIMARANER"
+    SAME = "SAME"
+
+
+class Cat(BaseUniqueSortedEnum):
+    BRITISH = "BRITISH"
+    SCOTTISH = "SCOTTISH"
+    SAME = "SAME"
+
+
+assert Dog.BLOODHOUND < Dog.WEIMARANER
+assert Dog.BLOODHOUND <= Dog.WEIMARANER
+assert Dog.BLOODHOUND != Dog.WEIMARANER
+assert Dog.BLOODHOUND == Dog.BLOODHOUND
+assert Dog.WEIMARANER == Dog.WEIMARANER
+assert Dog.WEIMARANER > Dog.BLOODHOUND
+assert Dog.WEIMARANER >= Dog.BLOODHOUND
+
+assert Cat.BRITISH < Cat.SCOTTISH
+assert Cat.BRITISH <= Cat.SCOTTISH
+assert Cat.BRITISH != Cat.SCOTTISH
+assert Cat.BRITISH == Cat.BRITISH
+assert Cat.SCOTTISH == Cat.SCOTTISH
+assert Cat.SCOTTISH > Cat.BRITISH
+assert Cat.SCOTTISH >= Cat.BRITISH
+
+assert hash(Dog.BLOODHOUND) == hash(Dog.BLOODHOUND)
+assert hash(Dog.WEIMARANER) == hash(Dog.WEIMARANER)
+assert hash(Dog.BLOODHOUND) != hash(Dog.WEIMARANER)
+assert hash(Dog.SAME) != hash(Cat.SAME)
+
+# raise TypeError
+Dog.SAME <= Cat.SAME
+Dog.SAME < Cat.SAME
+Dog.SAME > Cat.SAME
+Dog.SAME >= Cat.SAME
+Dog.SAME != Cat.SAME
+```
+
 # Contributing
 
 * Your contributions are always welcome!
diff --git a/python/enums.py b/python/enums.py
new file mode 100644
index 0000000..a53dc88
--- /dev/null
+++ b/python/enums.py
@@ -0,0 +1,71 @@
+import enum
+from functools import total_ordering
+
+
+@total_ordering
+@enum.unique
+class BaseUniqueSortedEnum(enum.Enum):
+    """Base unique enum class with ordering."""
+
+    def __new__(cls, *args, **kwargs):
+        obj = object.__new__(cls)
+        obj.index = len(cls.__members__) + 1
+        return obj
+
+    def __hash__(self) -> int:
+        return hash(
+          f"{self.__module__}_{self.__class__.__name__}_{self.name}_{self.value}"
+        )
+
+    def __eq__(self, other) -> bool:
+        self._check_type(other)
+        return super().__eq__(other)
+
+    def __lt__(self, other) -> bool:
+        self._check_type(other)
+        return self.index < other.index
+
+    def _check_type(self, other) -> None:
+        if type(self) != type(other):
+            raise TypeError(f"Different types of Enum: {self} != {other}")
+
+
+class Dog(BaseUniqueSortedEnum):
+    BLOODHOUND = "BLOODHOUND"
+    WEIMARANER = "WEIMARANER"
+    SAME = "SAME"
+
+
+class Cat(BaseUniqueSortedEnum):
+    BRITISH = "BRITISH"
+    SCOTTISH = "SCOTTISH"
+    SAME = "SAME"
+
+
+assert Dog.BLOODHOUND < Dog.WEIMARANER
+assert Dog.BLOODHOUND <= Dog.WEIMARANER
+assert Dog.BLOODHOUND != Dog.WEIMARANER
+assert Dog.BLOODHOUND == Dog.BLOODHOUND
+assert Dog.WEIMARANER == Dog.WEIMARANER
+assert Dog.WEIMARANER > Dog.BLOODHOUND
+assert Dog.WEIMARANER >= Dog.BLOODHOUND
+
+assert Cat.BRITISH < Cat.SCOTTISH
+assert Cat.BRITISH <= Cat.SCOTTISH
+assert Cat.BRITISH != Cat.SCOTTISH
+assert Cat.BRITISH == Cat.BRITISH
+assert Cat.SCOTTISH == Cat.SCOTTISH
+assert Cat.SCOTTISH > Cat.BRITISH
+assert Cat.SCOTTISH >= Cat.BRITISH
+
+assert hash(Dog.BLOODHOUND) == hash(Dog.BLOODHOUND)
+assert hash(Dog.WEIMARANER) == hash(Dog.WEIMARANER)
+assert hash(Dog.BLOODHOUND) != hash(Dog.WEIMARANER)
+assert hash(Dog.SAME) != hash(Cat.SAME)
+
+# raise TypeError
+Dog.SAME <= Cat.SAME
+Dog.SAME < Cat.SAME
+Dog.SAME > Cat.SAME
+Dog.SAME >= Cat.SAME
+Dog.SAME != Cat.SAME