feat: Support hist/hist division if view supports it

src/boost_histogram/_internal/hist.py

@@ -172,17 +172,35 @@ def __imul__(self, other):
         return self
 
     def __truediv__(self, other):
-        return self.__class__(self._hist.__truediv__(_hist_or_val(other)))
+        if isinstance(other, BaseHistogram):
+            result = self.copy()
+            result.__itruediv__(other)
+            return result
+        else:
+            return self.__class__(self._hist.__truediv__(_hist_or_val(other)))
 
     def __div__(self, other):
-        return self.__class__(self._hist.__div__(_hist_or_val(other)))
+        if isinstance(other, BaseHistogram):
+            result = self.copy()
+            result.__idiv__(other)
+            return result
+        else:
+            return self.__class__(self._hist.__div__(_hist_or_val(other)))
 
     def __itruediv__(self, other):
-        self._hist.__itruediv__(_hist_or_val(other))
+        if isinstance(other, BaseHistogram):
+            view = self.view(flow=True)
+            view.__itruediv__(other.view(flow=True))
+        else:
+            self._hist.__itruediv__(_hist_or_val(other))
         return self
 
     def __idiv__(self, other):
-        self._hist.__idiv__(_hist_or_val(other))
+        if isinstance(other, BaseHistogram):
+            view = self.view(flow=True)
+            view.__idiv__(other.view(flow=True))
+        else:
+            self._hist.__idiv__(_hist_or_val(other))
         return self
 
     def __copy__(self):

tests/test_histogram.py

@@ -473,6 +473,24 @@ def test_operators():
         h + h2
 
 
+def test_hist_hist_div():
+    h1 = bh.Histogram(bh.axis.Boolean())
+    h2 = bh.Histogram(bh.axis.Boolean())
+
+    h1[:] = (8, 6)
+    h2[:] = (2, 3)
+
+    h3 = h1 / h2
+
+    assert h3[False] == 4
+    assert h3[True] == 2
+
+    h1 /= h2
+
+    assert h1[False] == 4
+    assert h1[True] == 2
+
+
 def test_project():
     h = bh.Histogram(bh.axis.Integer(0, 2), bh.axis.Integer(1, 4))
     h.fill(0, 1)