feat: support conversion, AxesTuple subclass, get/setattr

docs/CHANGELOG.md

@@ -5,18 +5,21 @@
 
 #### User changes
 
-* Arbitrary items can be set on an axis or histogram. [#450][]
+* Arbitrary items can be set on an axis or histogram. [#450][], [#456][]
+* Subclasses can customize the conversion procedure. [#456][]
 
 #### Bug fixes
 
 * Fixed reading pickles from boost-histogram 0.6-0.8 [#445][]
 * Minor correctness fix [#446][]
 * Accidental install of typing on Python 3.5+ fixed
+* Scalar ND fill fixed [#453][]
 
 #### Developer changes
 * Updated to Boost 1.74 [#442][]
 * CMake installs version.py now too [#449][]
 * Updated setuptools infrastructure no longer requires NumPy [#451][]
+* Some basic clang-tidy checks are now being run [#455][]
 
 
 [#442]: https://github.com/scikit-hep/boost-histogram/pull/442
@@ -25,6 +28,9 @@
 [#449]: https://github.com/scikit-hep/boost-histogram/pull/449
 [#450]: https://github.com/scikit-hep/boost-histogram/pull/450
 [#451]: https://github.com/scikit-hep/boost-histogram/pull/451
+[#453]: https://github.com/scikit-hep/boost-histogram/pull/453
+[#455]: https://github.com/scikit-hep/boost-histogram/pull/455
+[#456]: https://github.com/scikit-hep/boost-histogram/pull/456
 
 
 ## Version 0.10

src/boost_histogram/_internal/axistuple.py → src/boost_histogram/_internal/axestuple.py

@@ -49,15 +49,6 @@ class AxesTuple(tuple):
     def size(self):
         return tuple(s.size for s in self)
 
-    @property
-    def metadata(self):
-        return tuple(s.metadata for s in self)
-
-    @metadata.setter
-    def metadata(self, values):
-        for s, v in zip(self, values):
-            s.metadata = v
-
     @property
     def extent(self):
         return tuple(s.extent for s in self)
@@ -102,6 +93,12 @@ def __getitem__(self, item):
         result = super(AxesTuple, self).__getitem__(item)
         return self.__class__(result) if isinstance(result, tuple) else result
 
+    def __getattr__(self, attr):
+        return self.__class__(s.__getattr__(attr) for s in self)
+
+    def __setattr__(self, attr, values):
+        return self.__class__(s.__setattr__(attr, v) for s, v in zip(self, values))
+
     # Python 2 support - remove after 1.0
     def __getslice__(self, start, stop):
         result = super(AxesTuple, self).__getslice__(start, stop)

src/boost_histogram/_internal/axis.py

@@ -45,16 +45,16 @@ def __getattr__(self, item):
         elif item == "metadata":
             return None
         else:
-            raise AttributeError(
-                "'{}' object has no attribute '{}'".format(type(self).__name__, item)
+            msg = "'{}' object has no attribute '{}' in {}".format(
+                type(self).__name__, item, set(self._ax.metadata)
             )
+            raise AttributeError(msg)
 
     def __setattr__(self, item, value):
         if item == "_ax":
             Axis.__dict__[item].__set__(self, value)
-            return
-
-        self._ax.metadata[item] = value
+        else:
+            self._ax.metadata[item] = value
 
     def __dir__(self):
         metadata = list(self._ax.metadata)

src/boost_histogram/_internal/hist.py

@@ -10,7 +10,7 @@
 
 from .. import _core
 from .axis import Axis
-from .axistuple import AxesTuple
+from .axestuple import AxesTuple
 from .kwargs import KWArgs
 from .sig_tools import inject_signature
 from .six import string_types
@@ -112,10 +112,11 @@ def __init__(self, *axes, **kwargs):
             self.axes = self._generate_axes_()
             return
 
-        # If we construct with another Histogram, support that too
+        # If we construct with another Histogram as the only positional argument,
+        # support that too
         if len(axes) == 1 and isinstance(axes[0], Histogram):
             self.__init__(axes[0]._hist)
-            self.metadata = axes[0].metadata
+            self._from_histogram_object(axes[0])
             return
 
         # Keyword only trick (change when Python2 is dropped)
@@ -151,6 +152,31 @@ def __init__(self, *axes, **kwargs):
 
         raise TypeError("Unsupported storage")
 
+    def _from_histogram_object(self, h):
+        self.__dict__ = copy.copy(h.__dict__)
+        self.axes = self._generate_axes_()
+        for ax in self.axes:
+            ax._ax.metadata = copy.copy(ax._ax.metadata)
+
+        # Allow custom behavior on either "from" or "to"
+        h._export_bh_(self)
+        self._import_bh_()
+
+    def _import_bh_(self):
+        """
+        If any post-processing is needed to pass a histogram between libraries, a
+        subclass can implement it here. self is the new instance in the current
+        (converted-to) class.
+        """
+
+    @classmethod
+    def _export_bh_(cls, self):
+        """
+        If any preparation is needed to pass a histogram between libraries, a subclass can
+        implement it here. cls is the current class being converted from, and self is the
+        instance in the class being converted to.
+        """
+
     def _generate_axes_(self):
         """
         This is called to fill in the axes. Subclasses can override it if they need

src/boost_histogram/axis/__init__.py

@@ -10,7 +10,7 @@
     StrCategory,
     Boolean,
 )
-from .._internal.axistuple import ArrayTuple, AxesTuple
+from .._internal.axestuple import ArrayTuple, AxesTuple
 from .._core.axis import options
 from . import transform
 

tests/test_histogram_indexing.py

@@ -331,7 +331,7 @@ def test_pick_int_category():
 
 def test_axes_tuple():
     h = bh.Histogram(bh.axis.Regular(10, 0, 1))
-    assert isinstance(h.axes[:1], bh._internal.axistuple.AxesTuple)
+    assert isinstance(h.axes[:1], bh._internal.axestuple.AxesTuple)
     assert isinstance(h.axes[0], bh.axis.Regular)
 
     (before,) = h.axes.centers[:1]
@@ -344,7 +344,7 @@ def test_axes_tuple_Nd():
     h = bh.Histogram(
         bh.axis.Integer(0, 5), bh.axis.Integer(0, 4), bh.axis.Integer(0, 6)
     )
-    assert isinstance(h.axes[:2], bh._internal.axistuple.AxesTuple)
+    assert isinstance(h.axes[:2], bh._internal.axestuple.AxesTuple)
     assert isinstance(h.axes[1], bh.axis.Integer)
 
     b1, b2 = h.axes.centers[1:3]

tests/test_minihist_title.py

@@ -0,0 +1,145 @@
+# -*- coding: utf-8 -*-
+# The point of this test is to make sure that the infrastructure for supporting
+# custom attributes, like title in Hist, is working.
+
+import pytest
+import boost_histogram as bh
+
+
+# First, make a new family to identify your library
+CUSTOM_FAMILY = object()
+
+
+# Add named axes
+class NamedAxesTuple(bh.axis.AxesTuple):
+    __slots__ = ()
+
+    def _get_index_by_name(self, name):
+        if isinstance(name, str):
+            for i, ax in enumerate(self):
+                if ax.name == name:
+                    return i
+            raise KeyError("{} not found in axes".format(name))
+        else:
+            return name
+
+    def __getitem__(self, item):
+        if isinstance(item, slice):
+            item = slice(
+                self._get_index_by_name(item.start),
+                self._get_index_by_name(item.stop),
+                self._get_index_by_name(item.step),
+            )
+        else:
+            item = self._get_index_by_name(item)
+
+        return super(NamedAxesTuple, self).__getitem__(item)
+
+    @property
+    def name(self):
+        """
+        The names of the axes. May be empty strings.
+        """
+        return tuple(ax.name for ax in self)
+
+
+# When you subclass Histogram or an Axes, you should register your family so
+# boost-histogram will know what to convert C++ objects into.
+
+
+class AxesMixin(object):
+    __slots__ = ()
+
+    @property
+    def name(self):
+        """
+        Get the name for the Regular axis
+        """
+        return self._ax.metadata.get("name", "")
+
+
+# The order of the mixin is important here - it must be first
+# to override bh.axis.Regular
+@bh.utils.set_family(CUSTOM_FAMILY)
+class Regular(bh.axis.Regular, AxesMixin):
+    __slots__ = ()
+
+    def __init__(
+        self, bins, start, stop, name,
+    ):
+
+        super(Regular, self).__init__(
+            bins, start, stop,
+        )
+
+        self._ax.metadata["name"] = name
+
+
+@bh.utils.set_family(CUSTOM_FAMILY)
+class CustomHist(bh.Histogram):
+    def _generate_axes_(self):
+        return NamedAxesTuple(self._axis(i) for i in range(self.ndim))
+
+    def __init__(self, *args, **kwargs):
+        super(CustomHist, self).__init__(*args, **kwargs)
+        valid_names = [ax.name for ax in self.axes if ax.name]
+        if len(valid_names) != len(set(valid_names)):
+            msg = "{} instance cannot contain axes with duplicated names".format(
+                self.__class__.__name__
+            )
+            raise KeyError(msg)
+
+
+def test_hist_creation():
+    hist_1 = CustomHist(Regular(10, 0, 1, name="a"), Regular(20, 0, 4, name="b"))
+    assert hist_1.axes[0].name == "a"
+    assert hist_1.axes[1].name == "b"
+
+    hist_2 = CustomHist(Regular(10, 0, 1, name=""), Regular(20, 0, 4, name=""))
+    assert hist_2.axes[0].name == ""
+    assert hist_2.axes[1].name == ""
+
+    with pytest.raises(KeyError):
+        CustomHist(Regular(10, 0, 1, name="a"), Regular(20, 0, 4, name="a"))
+
+
+def test_hist_index():
+    hist_1 = CustomHist(Regular(10, 0, 1, name="a"), Regular(20, 0, 4, name="b"))
+    assert hist_1.axes[0].name == "a"
+    assert hist_1.axes[1].name == "b"
+
+
+def test_hist_convert():
+    hist_1 = CustomHist(Regular(10, 0, 1, name="a"), Regular(20, 0, 4, name="b"))
+    hist_bh = bh.Histogram(hist_1)
+
+    assert type(hist_bh.axes[0]) == bh.axis.Regular
+    assert hist_bh.axes[0].name == "a"
+    assert hist_bh.axes[1].name == "b"
+
+    hist_2 = CustomHist(hist_bh)
+
+    assert type(hist_2.axes[0]) == Regular
+    assert hist_2.axes[0].name == "a"
+    assert hist_2.axes[1].name == "b"
+
+    # Just verify no-op status
+    hist_3 = CustomHist(hist_1)
+
+    assert type(hist_3.axes[0]) == Regular
+    assert hist_3.axes[0].name == "a"
+    assert hist_3.axes[1].name == "b"
+
+
+def test_access():
+    hist = CustomHist(Regular(10, 0, 1, name="a"), Regular(20, 0, 4, name="b"))
+
+    assert hist.axes["a"] == hist.axes[0]
+    assert hist.axes["b"] == hist.axes[1]
+
+    from_bh = bh.Histogram(bh.axis.Regular(10, 0, 1), bh.axis.Regular(20, 0, 4))
+    from_bh.axes.name = "a", "b"
+    hist_conv = CustomHist(from_bh)
+
+    assert hist_conv.axes["a"] == hist_conv.axes[0]
+    assert hist_conv.axes["b"] == hist_conv.axes[1]