Remove final _to_ function

Author: henryiii

boost_histogram/_internal/axis.py

@@ -8,7 +8,7 @@
 
 from .kwargs import KWArgs
 from .sig_tools import inject_signature
-from .axis_transform import AxisTransform, _to_transform
+from .axis_transform import AxisTransform
 from .utils import cast, register
 
 
@@ -183,7 +183,7 @@ def _repr_kwargs(self):
     @property
     def transform(self):
         if hasattr(self._ax, "transform"):
-            return _to_transform(self._ax.transform)
+            return cast(self._ax.transform, AxisTransform)
         return None
 
     @inject_signature(

boost_histogram/_internal/axis_transform.py

@@ -4,6 +4,8 @@
 
 from .._core import axis as ca
 
+from .utils import register
+
 
 class AxisTransform(object):
     __slots__ = ()
@@ -15,27 +17,23 @@ def _produce(self, bins, start, stop, metadata):
         return self.__class__._type(bins, start, stop, metadata)
 
 
+@register(ca.transform.log)
 class Log(ca.transform.log, AxisTransform):
     __slots__ = ()
     _type = ca.regular_log
 
 
+@register(ca.transform.sqrt)
 class Sqrt(ca.transform.sqrt, AxisTransform):
     __slots__ = ()
     _type = ca.regular_sqrt
 
 
+@register(ca.transform.pow)
 class Pow(ca.transform.pow, AxisTransform):
     __slots__ = ()
     _type = ca.regular_pow
 
     # This one does need to be a normal method
     def _produce(self, bins, start, stop, metadata):
         return self.__class__._type(bins, start, stop, self.power, metadata)
-
-
-def _to_transform(trans):
-    for trans_class in AxisTransform.__subclasses__():
-        if isinstance(trans, trans_class.__bases__):
-            return trans_class(trans)
-    raise TypeError("Cannot find transform")