Simplify {b && {r1:...:rn}} as {b && r1 && ... && rn}.

* src/ltlvisit/simplify.cc (simplify_visitor): Do it.
* src/ltltest/reduccmp.test: Add a test.
* doc/tl/tl.tex: Document it.
* src/ltlast/multop.cc: Fix the computation of is.accepting_eword
for Fusion.  The Fusion operator never accepts [*0].

doc/tl/tl.tex

@@ -1267,7 +1267,9 @@ in the OR arguments:
 
 \subsubsection{Basic Simplifications for SERE Operators}
 
-% Cite Symbolic computation of PSL.
+\spottodo[inline]{These rules, mostly taken from ``Symbolic
+  computation of PSL'' (Cimatti, Roveri, and Tonetta) are not complete
+  yet.}
 
 The following simplification rules are used for the $n$-ary operators
 $\ANDALT$, $\AND$, and $\OR$, and are of course commutative.
@@ -1288,6 +1290,7 @@ $\ANDALT$, $\AND$, and $\OR$, and are of course commutative.
     b \ANDALT r &\text{if~} i\le 1\le j\\
     \0 &\text{else}\\
   \end{cases}\\
+  b \ANDALT \ratgroup{r_1 \FUSION \ldots \FUSION r_n}& \equiv b \ANDALT r_1 \ANDALT \ldots \ANDALT r_n \\
 \end{align*}
 
 \subsection{Simplifications for Eventual and Universal Formul\ae}

src/ltlast/multop.cc

@@ -43,8 +43,9 @@ namespace spot
 
       switch (op)
 	{
-	case Concat:
 	case Fusion:
+	  is.accepting_eword = false;
+	case Concat:
 	case AndNLM:
 	  // Note: AndNLM(p1,p2) is a Boolean formula, but it is
 	  // actually rewritten as And(p1,p2) by trivial identities

src/ltltest/reduccmp.test

@@ -210,6 +210,7 @@ for x in ../reduccmp ../reductaustr; do
      run 0 $x '{a && b && d[=2]} <>-> d' '0'
      run 0 $x '{a && b && d[->2..4]} <>-> d' '0'
      run 0 $x '{a && b && d[*2..]} <>-> d' '0'
+     run 0 $x '{a && { c* : b* : (g|h)*}} <>-> d' 'a & c & b & (g | h) & d'
      ;;
   esac
 

src/ltlvisit/simplify.cc

@@ -1944,7 +1944,28 @@ namespace spot
 				  *i = 0;
 				  break;
 				}
+			      case formula::MultOp:
+				{
+				  multop* r = down_cast<multop*>(*i);
+				  switch (r->op())
+				    {
+				    case multop::Fusion:
+				      {
+					//b && {r1:..:rn} = b && r1 && .. && rn
+					unsigned rs = r->size();
+					for (unsigned j = 0; j < rs; ++j)
+					  ares->push_back(r->nth(j)->clone());
+					r->destroy();
+					*i = 0;
+					break;
+				      }
 				    default:
+				      goto common;
+				    }
+				  break;
+				}
+			      default:
+			      common:
 				ares->push_back(*i);
 				*i = 0;
 				break;