add support for the weak property

This fixes #119.

* doc/org/tut21.org, doc/org/hoa.org, NEWS: Document it.
* src/twa/twa.hh: Support it in automata.
* src/twaalgos/hoa.cc, src/parseaut/parseaut.yy: Add I/O support.
* src/twaalgos/minimize.cc, src/twaalgos/totgba.cc: Set weak
automata on output.
* src/tests/complement.test, src/tests/parseaut.test,
src/tests/readsave.test, src/tests/remfin.test, src/tests/sccsimpl.test,
src/tests/wdba2.test, wrap/python/tests/automata-io.ipynb: Adjust.

NEWS

@@ -22,12 +22,16 @@ New in spot 1.99.5a (not yet released)
     Boolean argument.  This argument used to be optionnal (defaulting
     to True), but it no longer is.
 
+  * Automata now support the "weak" property in addition to the
+    previously supported "inherently-weak".
+
   * By default the HOA printer tries to not bloat the output with
     properties that are probably useless.  The HOA printer now has a
     new option "v" (use "-Hv" from the command line) to output more
     verbose "properties:".  This currently includes outputing
-    "no-univ-branch", and outputting "unambiguous" even for automata
+    "no-univ-branch", outputting "unambiguous" even for automata
-    already tagged as "deterministic".
+    already tagged as "deterministic", and "inherently-weak" even
+    for automata tagged as "weak".
 
   Python:
   * Add bindings for is_unambiguous().

doc/org/hoa.org

@@ -527,7 +527,7 @@ is parsed; this is for instance the case of =deterministic=,
 body of the file, and then return and error if what has been declared
 does not correspond to the reality.
 
-Some supported properties (like =inherently-weak=, =unambiguous=, or
+Some supported properties (like =weak=, =unambiguous=, or
 =stutter-invariant=) are not double-checked, because that would
 require too much additional operations.  Command-line tools that read
 HOA files all take a =--trust-hoa=no= option to ignore properties that
@@ -591,7 +591,8 @@ particular:
 | =unambiguous=       | trusted | yes    | as stored if (=-Hv= or not =deterministic=) | can be re-checked with =--check=unambiguous=           |
 | =stutter-invariant= | trusted | yes    | as stored                                   | can be re-checked with =--check=stuttering=            |
 | =stutter-sensitive= | trusted | yes    | as stored                                   | can be re-checked with =--check=stuttering=            |
-| =inherently-weak=   | trusted | yes    | as stored                                   |                                                        |
+| =weak=              | trusted | yes    | as stored                                   |                                                        |
+| =inherently-weak=   | trusted | yes    | as stored if (=-Hv= or not =weak=)          |                                                        |
 | =colored=           | ignored | no     | checked                                     |                                                        |
 
 ** Named properties

doc/org/tut21.org

@@ -85,7 +85,7 @@ corresponding BDD variable number, and then use for instance
 
   void custom_print(std::ostream& out, spot::twa_graph_ptr& aut)
   {
-    // We need the dictionary to print the BDD that labels the edge
+    // We need the dictionary to print the BDDs that label the edges
     const auto& dict = aut->get_dict();
 
     // Some meta-data...
@@ -119,6 +119,8 @@ corresponding BDD variable number, and then use for instance
         << (aut->prop_unambiguous() ? "yes\n" : "maybe\n");
     out << "State-Based Acc: "
         << (aut->prop_state_acc() ? "yes\n" : "maybe\n");
+    out << "Weak: "
+        << (aut->prop_weak() ? "yes\n" : "maybe\n");
     out << "Inherently Weak: "
         << (aut->prop_inherently_weak() ? "yes\n" : "maybe\n");
     out << "Stutter Invariant: "
@@ -158,6 +160,7 @@ Name: Fa | G(Fb & Fc)
 Deterministic: maybe
 Unambiguous: yes
 State-Based Acc: maybe
+Weak: maybe
 Inherently Weak: maybe
 Stutter Invariant: yes
 State 0:

src/parseaut/parseaut.yy

@@ -436,8 +436,10 @@ header: format-version header-items
 	      res.h->aut->prop_stutter_sensitive(ss);
 	      bool iw = res.props.find("inherently-weak") != e;
 	      res.h->aut->prop_inherently_weak(iw);
-	      bool iu = res.props.find("unambiguous") != e;
+	      bool wk = res.props.find("weak") != e;
-	      res.h->aut->prop_unambiguous(iu);
+	      res.h->aut->prop_weak(wk);
+	      bool un = res.props.find("unambiguous") != e;
+	      res.h->aut->prop_unambiguous(un);
 	    }
 	}
 

src/tests/complement.test

@@ -78,7 +78,7 @@ AP: 1 "a"
 acc-name: co-Buchi
 Acceptance: 1 Fin(0)
 properties: trans-labels explicit-labels state-acc complete
-properties: deterministic inherently-weak
+properties: deterministic weak
 --BODY--
 State: 0
 [0] 2

src/tests/parseaut.test

@@ -1189,8 +1189,7 @@ run 2 ../ikwiad -XH foob 2>output.err
 grep 'foob:1.1: Cannot open file foob' output.err
 
 # Make sure we can read multiple automata from stdin
-../../bin/ltl2tgba 'a U b' 'GFa' --hoa | grep -v '^name:' |
+../../bin/ltl2tgba 'a U b' 'GFa' --hoa | grep -v '^name:' > input
-    sed 's/ stutter-invariant//;s/ inherently-weak//;/properties:$/d' > input
 ../../bin/autfilt --hoa < input | ../../bin/autfilt --hoa > output
 diff input output
 

src/tests/readsave.test

@@ -726,8 +726,7 @@ Start: 1
 AP: 2 "a" "b"
 acc-name: Buchi
 Acceptance: 1 Inf(0)
-properties: trans-labels explicit-labels state-acc deterministic
+properties: trans-labels explicit-labels state-acc deterministic weak
-properties: inherently-weak
 --BODY--
 State: 0
 [1] 2
@@ -752,7 +751,7 @@ AP: 2 "a" "b"
 acc-name: Buchi
 Acceptance: 1 Inf(0)
 properties: no-univ-branch trans-labels explicit-labels state-acc
-properties: deterministic unambiguous inherently-weak
+properties: deterministic unambiguous weak inherently-weak
 --BODY--
 State: 0
 [1] 2

src/tests/remfin.test

@@ -602,7 +602,7 @@ AP: 0
 acc-name: all
 Acceptance: 0 t
 properties: trans-labels explicit-labels state-acc deterministic
-properties: stutter-invariant inherently-weak
+properties: stutter-invariant weak
 --BODY--
 State: 0
 --END--

src/tests/sccsimpl.test

@@ -316,7 +316,7 @@ AP: 1 "p0"
 acc-name: Buchi
 Acceptance: 1 Inf(0)
 properties: trans-labels explicit-labels state-acc complete
-properties: deterministic inherently-weak
+properties: deterministic weak
 --BODY--
 State: 0 {0}
 [t] 0
@@ -331,7 +331,7 @@ AP: 1 "p0"
 acc-name: Buchi
 Acceptance: 1 Inf(0)
 properties: trans-labels explicit-labels state-acc complete
-properties: deterministic inherently-weak
+properties: deterministic weak
 --BODY--
 State: 0 {0}
 [t] 0

src/tests/wdba2.test

@@ -67,8 +67,7 @@ Start: 2
 AP: 1 "p1"
 acc-name: Buchi
 Acceptance: 1 Inf(0)
-properties: implicit-labels state-acc complete deterministic
+properties: implicit-labels state-acc complete deterministic weak
-properties: inherently-weak
 --BODY--
 State: 0 {0}
 0 0

src/twa/twa.hh

@@ -755,7 +755,8 @@ namespace spot
     struct bprop
     {
       bool state_based_acc:1;	// State-based acceptance.
-      bool inherently_weak:1;	// Weak automaton.
+      bool inherently_weak:1;	// Inherently Weak automaton.
+      bool weak:1;		// Weak automaton.
       bool deterministic:1;	// Deterministic automaton.
       bool unambiguous:1;	// Unambiguous automaton.
       bool stutter_invariant:1;	// Stutter invariant language.
@@ -830,6 +831,19 @@ namespace spot
       is.inherently_weak = val;
     }
 
+    bool prop_weak() const
+    {
+      return is.weak;
+    }
+
+    void prop_weak(bool val)
+    {
+      if (val)
+	is.inherently_weak = is.weak = true;
+      else
+	is.weak = false;
+    }
+
     bool prop_deterministic() const
     {
       return is.deterministic;
@@ -882,9 +896,9 @@ namespace spot
     struct prop_set
     {
       bool state_based;
-      bool inherently_weak;
+      bool inherently_weak;	// and weak
-      bool deterministic;
+      bool deterministic;	// and unambiguous
-      bool stutter_inv;
+      bool stutter_inv;		// and stutter_sensitive
 
       static prop_set all()
       {
@@ -899,7 +913,10 @@ namespace spot
       if (p.state_based)
 	prop_state_acc(other->prop_state_acc());
       if (p.inherently_weak)
-	prop_inherently_weak(other->prop_inherently_weak());
+	{
+	  prop_weak(other->prop_weak());
+	  prop_inherently_weak(other->prop_inherently_weak());
+	}
       if (p.deterministic)
 	{
 	  prop_deterministic(other->prop_deterministic());
@@ -917,7 +934,10 @@ namespace spot
       if (!p.state_based)
 	prop_state_acc(false);
       if (!p.inherently_weak)
-	prop_inherently_weak(false);
+	{
+	  prop_weak(false);
+	  prop_inherently_weak(false);
+	}
       if (!p.deterministic)
 	{
 	  prop_deterministic(false);

src/twaalgos/hoa.cc

@@ -425,7 +425,9 @@ namespace spot
       prop(" stutter-invariant");
     if (aut->prop_stutter_sensitive())
       prop(" stutter-sensitive");
-    if (aut->prop_inherently_weak())
+    if (aut->prop_weak())
+      prop(" weak");
+    if (aut->prop_inherently_weak() && (verbose || !aut->prop_weak()))
       prop(" inherently-weak");
     os << nl;
 

src/twaalgos/minimize.cc

@@ -482,7 +482,7 @@ namespace spot
     auto res = minimize_dfa(det_a, final, non_final);
     res->prop_copy(a, { false, false, false, true });
     res->prop_deterministic(true);
-    res->prop_inherently_weak(true);
+    res->prop_weak(true);
     res->prop_state_acc(true);
     return res;
   }
@@ -583,7 +583,7 @@ namespace spot
     auto res = minimize_dfa(det_a, final, non_final);
     res->prop_copy(a, { false, false, false, true });
     res->prop_deterministic(true);
-    res->prop_inherently_weak(true);
+    res->prop_weak(true);
     return res;
   }
 
@@ -605,7 +605,7 @@ namespace spot
 
     // If the input automaton was already weak and deterministic, the
     // output is necessary correct.
-    if (aut_f->prop_inherently_weak() && aut_f->prop_deterministic())
+    if (aut_f->prop_weak() && aut_f->prop_deterministic())
       return min_aut_f;
 
     // if f is a syntactic obligation formula, the WDBA minimization
@@ -654,7 +654,7 @@ namespace spot
     if (product(min_aut_f, aut_neg_f)->is_empty())
       {
 	// Complement the minimized WDBA.
-	assert(min_aut_f->prop_inherently_weak());
+	assert(min_aut_f->prop_weak());
 	auto neg_min_aut_f = remove_fin(dtwa_complement(min_aut_f));
 	if (product(aut_f, neg_min_aut_f)->is_empty())
 	  // Finally, we are now sure that it was safe

src/twaalgos/totgba.cc

@@ -335,7 +335,7 @@ namespace spot
 	res = make_twa_graph(aut->get_dict());
 	res->set_init_state(res->new_state());
 	res->prop_state_acc(true);
-	res->prop_inherently_weak(true);
+	res->prop_weak(true);
 	res->prop_deterministic(true);
 	res->prop_stutter_invariant(true);
 	return res;

wrap/python/tests/automata-io.ipynb

@@ -60,7 +60,7 @@
         "acc-name: Buchi\n",
         "Acceptance: 1 Inf(0)\n",
         "properties: trans-labels explicit-labels state-acc deterministic\n",
-        "properties: stutter-invariant inherently-weak\n",
+        "properties: stutter-invariant weak\n",
         "--BODY--\n",
         "State: 0 {0}\n",
         "[t] 0\n",
@@ -198,7 +198,7 @@
         "acc-name: Buchi\r\n",
         "Acceptance: 1 Inf(0)\r\n",
         "properties: trans-labels explicit-labels state-acc deterministic\r\n",
-        "properties: stutter-invariant inherently-weak\r\n",
+        "properties: stutter-invariant weak\r\n",
         "--BODY--\r\n",
         "State: 0 {0}\r\n",
         "[t] 0\r\n",
@@ -859,4 +859,4 @@
    "metadata": {}
   }
  ]
-}
+}