Support braces in addition to parentheses in rational expressions.

* src/ltlparse/ltlparse.yy (rationalexp): Allow bracedrationalexp.
* src/ltltest/consterm.test, src/tgbatest/ltl2tgba.test: Add more
tests.

src/ltlparse/ltlparse.yy

@@ -234,6 +234,8 @@ booleanatom: ATOMIC_PROP
 rationalexp: booleanatom
 	    | CONST_EMPTYWORD
 	      { $$ = constant::empty_word_instance(); }
+            | bracedrationalexp
+	      { $$ = $1; }
 	    | PAR_OPEN rationalexp PAR_CLOSE
 	      { $$ = $2; }
 	    | PAR_OPEN error PAR_CLOSE

src/ltltest/consterm.test

@@ -37,6 +37,7 @@ run 1 ../consterm '((a ; b) + #e)'
 run 0 ../consterm '((a ; b) + #e) & e'
 run 1 ../consterm '((a ; b) + #e) & #e'
 run 1 ../consterm '((a ; b) + #e) & (a* + b)'
+run 1 ../consterm '{{a ; b} + {#e}} & {a* + b}'  # test braces
 run 1 ../consterm '(a + #e);(b + #e);(c + #e)'
 run 0 ../consterm '(a + #e);(b + e);(c + #e)'
 run 1 ../consterm '(a + #e);(b + e)*;(c + #e)'

src/tgbatest/ltl2tgba.test

@@ -66,7 +66,7 @@ check_psl '{((a*;b;c)*)&((b*;a;c)*)}<>->x'
 check_psl '{(g;y;r)*}<>->x'
 check_psl 'G({(g;y;r)*}<>->x)'
 check_psl 'G({(a;b)*}<>->x)&G({(c;d)*}<>->y)'
-check_psl 'G({(a;b)*}<>->x)&G({(c;d)*}<>->y)'
+check_psl 'G({{a;b}*}[]->x)&G({{c;d}*}[]->y)' # try sub-braces
 check_psl '{(#e + a):c*:(#e + b)}<>->d'
 check_psl '{a;e;f:(g*);h}<>->d'
 check_psl '{(a:b)* & (c*:d)}<>->e'