From a5fc1a648a4fcf768c3bf7a9432ce21bd63e47ff Mon Sep 17 00:00:00 2001
From: Tom Schierenbeck <tom_sch@uni-bremen.de>
Date: Tue, 11 Jun 2024 11:36:20 +0200
Subject: [PATCH] Added singleton checking methods. SimpleSet now inherits from
 int.

---
 src/random_events/__init__.py |  2 +-
 src/random_events/interval.py | 14 +++++++++++---
 src/random_events/set.py      |  7 ++++++-
 test/test_set.py              |  2 +-
 4 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/src/random_events/__init__.py b/src/random_events/__init__.py
index b7a5531..da4039b 100644
--- a/src/random_events/__init__.py
+++ b/src/random_events/__init__.py
@@ -1 +1 @@
-__version__ = '3.0.1'
+__version__ = '3.0.2'
diff --git a/src/random_events/interval.py b/src/random_events/interval.py
index cab0419..413d106 100644
--- a/src/random_events/interval.py
+++ b/src/random_events/interval.py
@@ -76,6 +76,12 @@ def is_empty(self) -> bool:
         return self.lower > self.upper or (
                 self.lower == self.upper and (self.left == Bound.OPEN or self.right == Bound.OPEN))
 
+    def is_singleton(self) -> bool:
+        """
+        :return: True if the interval is a singleton (contains only one value), False otherwise.
+        """
+        return self.lower == self.upper and self.left == Bound.CLOSED and self.right == Bound.CLOSED
+
     def intersection_with(self, other: Self) -> Self:
 
         # create new limits for the intersection
@@ -199,9 +205,11 @@ def new_empty_set(self) -> Self:
     def complement_if_empty(self) -> Self:
         return Interval([SimpleInterval(float('-inf'), float('inf'), Bound.OPEN, Bound.OPEN)])
 
-
-# Type definitions
-
+    def is_singleton(self):
+        """
+        :return: True if the interval is a singleton (contains only one value), False otherwise.
+        """
+        return len(self.simple_sets) == 1 and self.simple_sets[0].is_singleton()
 
 
 def open(left: float, right: float) -> Interval:
diff --git a/src/random_events/set.py b/src/random_events/set.py
index 5e902c5..791a220 100644
--- a/src/random_events/set.py
+++ b/src/random_events/set.py
@@ -7,16 +7,21 @@
 from .sigma_algebra import *
 
 
-class SetElement(AbstractSimpleSet, enum.Enum):
+class SetElement(AbstractSimpleSet, int, enum.Enum):
     """
     Base class for enums that are used as elements in a set.
 
     Classes that inherit from this class have to define an attribute called EMPTY_SET.
+    It is advisable to define EMPTY_SET as -1 to correctly work with indices.
+    The empty set of the class is used to access all other elements of the class.
     """
 
     @property
     @abstractmethod
     def EMPTY_SET(self):
+        """
+        :return: The empty set of the class.
+        """
         raise NotImplementedError("The EMPTY_SET attribute has to be defined.")
 
     @property
diff --git a/test/test_set.py b/test/test_set.py
index 421604a..a2073cf 100644
--- a/test/test_set.py
+++ b/test/test_set.py
@@ -6,7 +6,7 @@
 
 
 class TestEnum(SetElement):
-    EMPTY_SET = 0
+    EMPTY_SET = -1
     A = 1
     B = 2
     C = 4