Add back the '*' syntax for And.

This somehow revert changes from 2010-01-30 which killed this use of
star to make room for the Kleen star.  Here we only allow '*' in the
temporal formula, so that it can still be the Kleen star in SERE.  The
motivation for '*' available as And is better compatibility with Wring
and VIS.

* src/ltlparse/ltlscan.ll: Distinguish * from [*].
* src/ltlparse/ltlparse.yy: Allows * to be used as AND between
temporal formulae.
* src/ltltest/equals.test, src/ltltest/parse.test: Add a few
tests.
* doc/tl/tl.tex: Document it.

doc/tl/tl.tex

@@ -83,6 +83,7 @@
 \newcommand{\1}{\texttt{1}}
 \newcommand{\STAR}[1]{\texttt{[*#1]}}
 \newcommand{\STARALT}{\texttt{*}}
+\newcommand{\STARBIN}{\mathbin{\texttt{*}}}
 \newcommand{\EQUAL}[1]{\texttt{[=#1]}}
 \newcommand{\GOTO}[1]{\texttt{[->#1]}}
 \newcommand{\PLUS}{\texttt{[+]}}
@@ -361,12 +362,17 @@ following Boolean operators:
   \cmidrule(r){1-5} \cmidrule(l){6-7}
   negation    & $\NOT f$      & $\NOTALT f$      &                   &               & $\lnot$ \uni{00AC}  \\
   disjunction & $f\OR g$      & $f\ORALT g$      & $f\ORALTT g$      & $f\ORALTTT g$ & $\lor$ \uni{2228} & $\cup$ \uni{222A}\\
-  conjunction & $f\AND g$     & $f\ANDALT g$     & $f\ANDALTT g$     &               & $\land$ \uni{2227} & $\cap$ \uni{2229}\\
+  conjunction & $f\AND g$     & $f\ANDALT g$     & $f\ANDALTT g$     & $f\STARBIN g$\rlap{\footnotemark} & $\land$ \uni{2227} & $\cap$ \uni{2229}\\
   implication & $f\IMPLIES g$ & $f\IMPLIESALT g$ & $f\IMPLIESALTT g$ &               & $\limplies$ \uni{2192} & $\rightarrow$ \uni{27F6}, $\Rightarrow$ \uni{21D2} \uni{27F9} \\
   exclusion   & $f\XOR g$     & $f\XORALT g$     &                   &               & $\oplus$ \uni{2295} \\
   equivalence & $f\EQUIV g$   & $f\EQUIVALT g$   & $f\EQUIVALTT g$   &               & $\liff$ \uni{2194} & $\Leftrightarrow$ \uni{21D4}\\
 \end{tabular}
 \end{center}
+\footnotetext{The $\STARALT$-form of the conjunction operator
+  (allowing better compatibility with Wring and VIS) may only used in
+  temporal formul\ae.  Boolean expressions that occur inside SERE (see
+  Section~\ref{sec:sere}) may not use this form because the $\STARALT$
+  symbol is used as the Kleen star.}
 
 Additionally, an atomic proposition $a$ can be negated using the
 syntax \samp{$a$=0}, which is equivalent to \samp{$\NOT a$}.  Also
@@ -558,7 +564,7 @@ Among all the possible rewritings (see Appendix~\ref{sec:ltl-equiv})
 those two were chosen because they are easier to translate in a
 tableau construction~\cite[Fig.~11]{duret.11.vecos}.
 
-\section{SERE Operators}
+\section{SERE Operators}\label{sec:sere}
 
 The ``SERE'' acronym will be translated to different word depending on
 the source.  It can mean either ``\textit{Sequential Extended Regular

src/ltlparse/ltlparse.yy

@@ -104,7 +104,8 @@ using namespace spot::ltl;
 %token OP_U "until operator" OP_R "release operator"
 %token OP_W "weak until operator" OP_M "strong release operator"
 %token OP_F "sometimes operator" OP_G "always operator"
-%token OP_X "next operator" OP_NOT "not operator" OP_STAR "star operator"
+%token OP_X "next operator" OP_NOT "not operator"
+%token OP_STAR "star operator" OP_BSTAR "bracket star operator"
 %token OP_PLUS "plus operator"
 %token OP_STAR_OPEN "opening bracket for star operator"
 %token OP_EQUAL_OPEN "opening bracket for equal operator"
@@ -137,13 +138,19 @@ using namespace spot::ltl;
 %left OP_XOR
 %left OP_AND OP_SHORT_AND
 
+/* OP_STAR can be used as an AND when occurring in some LTL formula in
+   Wring's syntax (so it has to be close to OP_AND), and as a Kleen
+   Star in SERE (so it has to be close to OP_BSTAR -- luckily
+   U/R/M/W/F/G/X are not used in SERE). */
+%left OP_STAR
+
 /* LTL operators.  */
 %right OP_U OP_R OP_M OP_W
 %nonassoc OP_F OP_G
 %nonassoc OP_X
 
 /* High priority regex operator. */
-%nonassoc OP_STAR OP_STAR_OPEN OP_PLUS OP_EQUAL_OPEN OP_GOTO_OPEN
+%nonassoc OP_BSTAR OP_STAR_OPEN OP_PLUS OP_EQUAL_OPEN OP_GOTO_OPEN
 
 /* Not has the most important priority after Wring's `=0' and `=1'.  */
 %nonassoc OP_NOT
@@ -248,7 +255,9 @@ gotoargs: OP_GOTO_OPEN OP_SQBKT_NUM OP_SQBKT_SEP OP_SQBKT_NUM OP_SQBKT_CLOSE
                "missing closing bracket for goto operator"));
 	     $$.min = $$.max = 0U; }
 
-starargs: OP_STAR
+kleen_star: OP_STAR | OP_BSTAR
+
+starargs: kleen_star
             { $$.min = 0U; $$.max = bunop::unbounded; }
         | OP_PLUS
 	    { $$.min = 1U; $$.max = bunop::unbounded; }
@@ -606,6 +615,10 @@ subformula: booleanatom
 	      { $$ = multop::instance(multop::And, $1, $3); }
 	    | subformula OP_SHORT_AND error
               { missing_right_binop($$, $1, @2, "and operator"); }
+	    | subformula OP_STAR subformula
+	      { $$ = multop::instance(multop::And, $1, $3); }
+	    | subformula OP_STAR error
+              { missing_right_binop($$, $1, @2, "and operator"); }
 	    | subformula OP_OR subformula
 	      { $$ = multop::instance(multop::Or, $1, $3); }
 	    | subformula OP_OR error

src/ltlparse/ltlscan.ll

@@ -106,7 +106,8 @@ BOXDARROW {BOX}{DARROWL}|"|"{DARROWL}|"⤇"
 {DIAMOND}{DARROWL}		BEGIN(0); return token::OP_ECONCAT_NONO;
 ";"				BEGIN(0); return token::OP_CONCAT;
 ":"				BEGIN(0); return token::OP_FUSION;
-"*"|"[*]"			BEGIN(0); return token::OP_STAR;
+"*"				BEGIN(0); return token::OP_STAR;
+"[*]"				BEGIN(0); return token::OP_BSTAR;
 "[+]"				BEGIN(0); return token::OP_PLUS;
 "[*"				BEGIN(sqbracket); return token::OP_STAR_OPEN;
 "[="				BEGIN(sqbracket); return token::OP_EQUAL_OPEN;
@@ -141,7 +142,8 @@ BOXDARROW {BOX}{DARROWL}|"|"{DARROWL}|"⤇"
 
   /* & and | come from Spin.  && and || from LTL2BA.
      /\, \/, and xor are from LBTT.
-     --> and <--> come from Goal.  */
+     --> and <--> come from Goal.
+     +,*,^ are from Wring. */
 "||"|"|"|"+"|"\\/"|"∨"|"∪"	BEGIN(0); return token::OP_OR;
 "&&"|"/\\"|"∧"|"∩"		BEGIN(0); return token::OP_AND;
 "&"				BEGIN(0); return token::OP_SHORT_AND;

src/ltltest/equals.test

@@ -51,6 +51,7 @@ run 0 ../equals 'a & a & true' 'a'
 run 0 ../equals 'a & false & a' 'false'
 run 0 ../equals 'a | false | a' 'a'
 run 0 ../equals 'true | a | a' 'true'
+run 0 ../equals 'Ga=1*Gb=0' '(G(a)) & (G(!b))'
 
 # other formulae which are not
 run 1 ../equals 'a' 'b'

src/ltltest/parse.test

@@ -1,5 +1,5 @@
 #! /bin/sh
-# Copyright (C) 2009, 2010, 2011 Laboratoire de Recherche et Developpement
+# Copyright (C) 2009, 2010, 2011, 2012 Laboratoire de Recherche et Developpement
 # de l'Epita (LRDE).
 # Copyright (C) 2003, 2004 Laboratoire d'Informatique de Paris 6 (LIP6),
 # département Systèmes Répartis Coopératifs (SRC), Université Pierre
@@ -38,7 +38,7 @@ for f in \
   'p11011' \
   '(p11011)' \
   'a & b' \
-  'a & _b12' \
+  'a * _b12' \
   'a && .b.' \
   'a + b' \
   'a3214 | b' \
@@ -73,6 +73,8 @@ for f in \
   'a R ome V anille' \
   'p=0Uq=1' \
   '((p=1Rq=1)+p=0)UXq=0' \
+  '((p=1Rq=1)*p=0)UXq=0' \
+  '(Gq=1*Fp=0)UXq=0' \
   '((p=1Mq=1)Wx+p=0)RXq=0' \
   '((p=1Vq=1)Rx+p=0)WXq=0' \
   '((X(p2=0))U(X(p2=0)))+((Xp1=0)UFALSE)'