Make relations test more feature complete.

src/test/jastadd/relations/Relations.relast

@@ -41,3 +41,22 @@ rel A <- Root.AaLeft?;
 rel B <- A.Di1Left ;
 rel B <- A.Di2Left?;
 rel B <- A.Di3Left*;
+
+// empty productions
+C ;
+
+// production with nonterminals of different kinds
+D ::= SingleA:A ListOfA:A* [OptionalA:A] /NTAA:A/ ;
+
+// production with tokens, nonterminal-tokens, multi-line
+E ::= <T1> <T2:String> <T3:boolean> <T4:int> <T5:float> <T6:double> <T7:long>
+      /<NT2:String>/ /<NT3:boolean>/ /<NT4:int>/ /<NT5:float>/ /<NT6:double>/ /<NT7:long>/ ;
+
+// inheritance and empty
+F : A ;
+
+// inheritance and more on RHS
+G : C ::= [D] ;
+
+// line comment with special symbols like |, *, ->, <-, <->, [A], B ::= C, :, \n, \r, ~, #, /A/
+/* block comment with special symbols like |, *, ->, <-, <->, [A], B ::= C, :, \n, \r, ~, #, /A/ */