python: add __repr__ for rs_pair

* spot/twa/acc.hh: Hide default constructors, so that we can have
keyword arguments on the main constructor.
* python/spot/impl.i: Add __repr__.
* tests/python/setacc.py: Test it.

python/spot/impl.i

@@ -670,6 +670,29 @@ def state_is_accepting(self, src) -> "bool":
 %include <spot/taalgos/minimize.hh>
 
 
+%extend spot::acc_cond::rs_pair {
+  std::string __repr__()
+  {
+    std::ostringstream os;
+    os << "spot.rs_pair(fin=[";
+    char* sep = "";
+    for (unsigned s: self->fin.sets())
+      {
+        os << sep << s;
+        sep = ", ";
+      }
+    os << "], inf=[";
+    sep = "";
+    for (unsigned s: self->inf.sets())
+      {
+        os << sep << s;
+        sep = ", ";
+      }
+    os << "])";
+    return os.str();
+  }
+}
+
 %extend spot::trival {
   std::string __repr__()
   {

spot/twa/acc.hh

@@ -1135,8 +1135,10 @@ namespace spot
     /// false in Streett, and true in Rabin.
     struct SPOT_API rs_pair
     {
+#ifndef SWIG
       rs_pair() = default;
       rs_pair(const rs_pair&) = default;
+#endif
 
       rs_pair(acc_cond::mark_t fin, acc_cond::mark_t inf):
         fin(fin),

tests/python/setacc.py

@@ -50,8 +50,7 @@ assert b == False
 assert len(v) == 0
 (b, v) = spot.acc_cond("(Fin(0)|Inf(1))&(Fin(2)|Inf(0))").is_streett_like()
 assert b == True
-assert len(v) == 2
-assert v[0].fin == [0]
-assert v[0].inf == [1]
-assert v[1].fin == [2]
-assert v[1].inf == [0]
+assert repr(v) == \
+  '(spot.rs_pair(fin=[0], inf=[1]), spot.rs_pair(fin=[2], inf=[0]))'
+v2 = (spot.rs_pair(fin=[0], inf=[1]), spot.rs_pair(fin=[2], inf=[0]))
+assert v == v2