b2/: make "again" include the match; make "break" pop the stack

b2/SUBST

@@ -2,6 +2,16 @@ FN=DNP { ignore }
 
 FN=X(*) { $=$1 }
 
+/* iteration demo */
+FOO=abcde
+BAR=x	/* BAR= wouldn't be syntactically correct. We need a non-empty value */
+FOO=(*)(?) {
+	BAR=$BAR$2
+	FOO=$1
+	again FOO
+}
+BAR=x(*) { $=$1 }	/* remove the "x" */
+
 REF=R[0-9]* {
 	T=R
 	VAL=(#R) { R=$1 }