adds FiniteEnumeratedSet

[nthiery]

This patch adds sage.sets.finite_enumerated_set.FiniteEnumeratedSet?

depends on #5891

[nthiery]

Apply only this one (ignore the next one)

[hivert]

Since it's not yet integrated, I take the chance to solve this stupid bug:

sage: FiniteEnumeratedSet([1])
{1,}

I'm re-uploading a patch with the following folded in

diff --git a/sage/sets/finite_enumerated_set.py b/sage/sets/finite_enumerated_set.py
--- a/sage/sets/finite_enumerated_set.py
+++ b/sage/sets/finite_enumerated_set.py
@@ -123,8 +123,13 @@ class FiniteEnumeratedSet(UniqueRepresen
             sage: S = FiniteEnumeratedSet([1,2,3])
             sage: repr(S)
             '{1, 2, 3}'
+            sage: S = FiniteEnumeratedSet([1])
+            sage: repr(S)
+            '{1}'
         """
-        return "{"+str(self._elements)[1:-1] + '}'
+        if len(self._elements) == 1: # avoid printing '{1,}'
+            return "{" + str(self._elements[0]) + '}'
+        return "{" + str(self._elements)[1:-1] + '}'
 
     def __contains__(self, x):
         """

Florent

[hivert]

Please Nicolas (or anyone else re-view the small change.

Only trac_7403-finite-enumeratedsets-fh.3.patch should be applied on top of #5891

Cheers,

Florent