added printing formats.

test/cdata.in

-intlist = null | cons( int first, intlist next );
-illist  = null | cons( intlist first, illist next );
-idtree  = null | leaf( char * id ) | node( idtree left, idtree right );
-
+intlist = null "null" | cons( int first, intlist next ) 1 " , " 2;
+illist  = null "null" | cons( intlist first, illist next ) "[ " 1 " ] , " 2;
+idtree  = leaf( string id ) "leaf '" 1 "'"
+	| node( idtree left, idtree right ) "( " 1 " , " 2 " )";