From 64a37f600ab822cd7c86c3e5530faa1bfbfdcf07 Mon Sep 17 00:00:00 2001
From: Brent Baccala <cosine@freesoft.org>
Date: Mon, 4 Feb 2019 15:45:52 -0500
Subject: [PATCH] Trac #27220: allow different implementations to have their
 own differential classes

---
 src/sage/rings/function_field/differential.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/sage/rings/function_field/differential.py b/src/sage/rings/function_field/differential.py
index 06bbf0d9dae..8bbbbf4f22c 100644
--- a/src/sage/rings/function_field/differential.py
+++ b/src/sage/rings/function_field/differential.py
@@ -94,7 +94,7 @@ def differential(field, f, t=None):
     if t is not None:
         t = field(t)
 
-    return FunctionFieldDifferential_global(field, f, t)
+    return field.space_of_differentials().element_class(field, f, t)
 
 class FunctionFieldDifferential(ModuleElement):
     """
@@ -501,7 +501,7 @@ def _call_(self, v):
 
         """
         field = self.codomain().function_field()
-        return FunctionFieldDifferential_global(field, field(v._f))
+        return differential(field, v._f)
 
 class DifferentialMultiplicationAction(Action):
     """
@@ -581,6 +581,8 @@ class DifferentialsSpace(Parent):
     """
     Space of differentials of a function field.
     """
+    Element = FunctionFieldDifferential_global
+
     def __init__(self, field):
         """
         Initialize the space of differentials of the function field.