sage.repl.ipython_kernel (widget_from_tuple, slider): Handle symbolic…

… subrings like SR

src/sage/repl/ipython_kernel/interact.py

@@ -41,7 +41,7 @@
 from .widgets import EvalText, SageColorPicker
 from .widgets_sagenb import input_grid
 from sage.structure.element import parent
-from sage.symbolic.ring import SR
+import sage.rings.abc
 from sage.plot.colors import Color
 from sage.structure.element import Matrix
 
@@ -209,6 +209,14 @@ def widget_from_tuple(cls, abbrev, *args, **kwds):
             Dropdown(index=1, options={'one': 1, 'two': 2, 'three': 3}, value=2)
             sage: sage_interactive.widget_from_tuple( (sqrt(2), pi) )
             FloatSlider(value=2.277903107981444, max=3.141592653589793, min=1.4142135623730951)
+
+        TESTS:
+
+        Symbolic subrings::
+
+            sage: SCR = SR.subring(no_variables=True)
+            sage: sage_interactive.widget_from_tuple( (SCR(sqrt(2)), SCR(pi)) )
+            FloatSlider(value=2.277903107981444, max=3.141592653589793, min=1.4142135623730951)
         """
         # Support (description, abbrev)
         if len(abbrev) == 2 and isinstance(abbrev[0], str):
@@ -223,7 +231,7 @@ def widget_from_tuple(cls, abbrev, *args, **kwds):
         # Numerically evaluate symbolic expressions
 
         def n(x):
-            if parent(x) is SR:
+            if isinstance(parent(x), sage.rings.abc.SymbolicRing):
                 return x.numerical_approx()
             else:
                 return x

src/sage/repl/ipython_kernel/widgets_sagenb.py

@@ -42,8 +42,7 @@
 from sage.structure.all import parent
 from sage.arith.srange import srange
 from sage.plot.colors import Color
-from sage.symbolic.ring import SR
-from sage.rings.all import RR
+import sage.rings.abc
 
 
 from .widgets import HTMLText as text_control
@@ -234,6 +233,14 @@ def slider(vmin, vmax=None, step_size=None, default=None, label=None, display_va
         True
         sage: slider(5, display_value=False).readout
         False
+
+    Symbolic subrings work like ``SR``::
+
+        sage: SCR = SR.subring(no_variables=True)
+        sage: w = slider(SCR(e), SCR(pi)); w
+        TransformFloatSlider(value=2.718281828459045, max=3.141592653589793, min=2.718281828459045)
+        sage: parent(w.get_interact_value())
+        Real Field with 53 bits of precision
     """
     kwds = {"readout": display_value}
     if label:
@@ -271,7 +278,8 @@ def err(v):
     p = parent(sum(x for x in (vmin, vmax, step_size) if x is not None))
 
     # Change SR to RR
-    if p is SR:
+    if isinstance(p, sage.rings.abc.SymbolicRing):
+        from sage.rings.real_mpfr import RR
         p = RR
 
     # Convert all inputs to the common parent