feat: Support hist/hist division if view supports it (#393)

* feat: Support hist/hist division if view supports it

* doc: changelog

CHANGELOG.md

@@ -15,6 +15,8 @@ on Boost.Histogram's C++ tools for actions like cropping.
 * Slicing an AxesTuple now keeps the type [#384][]
 * `ndim` replaces `rank` for NumPy compatibility [#385][]
 * Any array-like supported in fill [#391][], any iterable can be used for Categories [#392][]
+* Added Boolean axes, from Boost.Histogram 1.74 [#390][]
+* Division between histograms is supported [#393][]
 * More deprecated functionality removed
 
 #### Bug fixes
@@ -25,7 +27,7 @@ on Boost.Histogram's C++ tools for actions like cropping.
 
 #### Developer changes
 
-* Update Boost to 1.73 [#359][], PyBind11 to 2.5.0 [#351][]
+* Update Boost to 1.73 [#359][], PyBind11 to 2.5.0 [#351][], Boost.Histogram to pre-1.74 [#388][]
 * Cropping no longer uses workaround [#373][]
 * Many more checks added to [`pre-commit`][] [#366][]
 * Deprecating `cpp` interface [#391][]
@@ -50,8 +52,11 @@ on Boost.Histogram's C++ tools for actions like cropping.
 [#384]: https://github.com/scikit-hep/boost-histogram/pull/384
 [#385]: https://github.com/scikit-hep/boost-histogram/pull/385
 [#386]: https://github.com/scikit-hep/boost-histogram/pull/386
+[#388]: https://github.com/scikit-hep/boost-histogram/pull/388
+[#390]: https://github.com/scikit-hep/boost-histogram/pull/390
 [#391]: https://github.com/scikit-hep/boost-histogram/pull/391
 [#392]: https://github.com/scikit-hep/boost-histogram/pull/392
+[#393]: https://github.com/scikit-hep/boost-histogram/pull/393
 
 
 ## Version 0.7.0

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)