Minor editorial changes, mainly to documentation.

Also, adding a __repr__ method to regtap.Interface that returns a
constructor call literal.

This is in response to
astropy#289 (review)

docs/registry/index.rst

@@ -43,7 +43,8 @@ keyword arguments.  The following constraints are available:
   freetext words, mached in the title, description or subject of the
   resource.
 * :py:class:`pyvo.registry.Servicetype` (``servicetype``): constrain to
-  one of tap, ssa, sia, conesearch.  This is the constraint you want
+  one of tap, ssa, sia, conesearch (or full ivoids for other service
+  types).  This is the constraint you want
   to use for service discovery.
 * :py:class:`pyvo.registry.UCD` (``ucd``): constrain by one or more UCD
   patterns; resources match when they serve columns having a matching

pyvo/registry/regtap.py

@@ -272,6 +272,10 @@ def __init__(self, access_url, standard_id, intf_type, intf_role):
         self.role = intf_role or None
         self.is_standard = self.role=="std"
 
+    def __repr__(self):
+        return (f"Interface({self.access_url!r}, {self.standard_id!r},"
+            f" {self.type!r}, {self.role!r})")
+
     def to_service(self):
         if self.type=="vr:webbrowser":
             return _BrowserService(self.access_url)

pyvo/registry/rtcons.py

@@ -494,16 +494,19 @@ class Spatial(Constraint):
 
         >>> registry.Spatial([23, -40, 26, -39, 25, -43])
 
-    To find resources claiming to cover a MOC, pass an ASCII MOC::
+    To find resources claiming to cover a MOC_, pass an ASCII MOC::
 
         >>> registry.Spatial("0/1-3 3/")
 
+    .. _MOC: https://www.ivoa.net/documents/MOC/
+
     When you already have an astropy SkyCoord::
 
         >>> from astropy.coordinates import SkyCoord
         >>> registry.Spatial(SkyCoord("23d +3d"))
 
-    SkyCoords also work as circle centers::
+    SkyCoords also work as circle centers (plain floats for the radius
+    are interpreted in degrees)::
 
         >>> registry.Spatial((SkyCoord("23d +3d"), 3))
     """
@@ -609,6 +612,7 @@ def __init__(self, spec):
             a frequency, or an energy, or a pair of such quantities,
             in which case the argument is interpreted as an interval.
             All resources *overlapping* the interval are returned.
+            Plain floats are interpreted as messenger energy in Joule.
         """
         if isinstance(spec, tuple):
             self._fillers = {

pyvo/registry/tests/test_regtap.py

@@ -208,6 +208,16 @@ def test_basic(self):
         assert intf.is_standard == False
         assert not intf.is_vosi
 
+    def test_repr(self):
+        intf = regtap.Interface("http://example.org", "ivo://gavo/std/a",
+            "vs:paramhttp", "std")
+        assert (repr(intf) == "Interface('http://example.org',"
+            " 'ivo://gavo/std/a', 'vs:paramhttp', 'std')")
+        intf = regtap.Interface("http://example.org", "ivo://gavo/std/a",
+            None, None)
+        assert repr(intf) == ("Interface('http://example.org',"
+            " 'ivo://gavo/std/a', None, None)")
+
     def test_unknown_standard(self):
         intf = regtap.Interface("http://example.org", "ivo://gavo/std/a",
             "vs:paramhttp", "std")