my range reversible example

python-temel/myrange.reversible.py

@@ -0,0 +1,52 @@
+class myrange:
+    def __init__(self, start, stop = None, step = 1):
+        if stop == None:
+            self._start = 0
+            self._stop = start
+        else:
+            self._start = start
+            self._stop = stop
+        self._step = step
+
+    def __iter__(self):
+        return myrange_iterator(self)
+
+    def __reversed__(self):
+        return myrange_reverse_iterator(self)
+
+class myrange_iterator:
+    def __init__(self, mr):
+        self._mr = mr
+        self._i = mr._start
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self._i >= self._mr._stop:
+            raise StopIteration
+        self._i += self._mr._step
+
+        return self._i - self._mr._step
+
+class myrange_reverse_iterator:
+    def __init__(self, mr):
+        self._mr = mr
+        self._i = mr._stop
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self._i <= self._mr._start:
+            raise StopIteration
+        self._i -= self._mr._step
+        return self._i
+
+for i in myrange(10):
+    print(i, end = ' ')
+print()
+
+for i in reversed(range(10)):
+    print(i, end = ' ')
+print()