diff --git a/pdf.c b/pdf.c
index 08ca4d5ade8514b46faccbbe353aa540491f9d7c..200dddf8071b24b77b06404b36c73bfecacc93e0 100644
--- a/pdf.c
+++ b/pdf.c
@@ -956,8 +956,10 @@ init_parser(struct Env *aux)
 				VIOL(h_optional(KW("endobj")), "Missing endobj token (severity=1)"))));
 	H_RULE(body,	h_many(objdef));
 
-	/* for object streams */
-	//H_RULE(osidx,	h_sepBy(npair, SEQ(wel,ws)));
+	/* for object streams XXX -> p_objstm__m(...) */
+	// sepBy_n(p, sep,n) = SEQ(p, REP(SEQ(sep, p), n-1))
+	//H_RULE(osidx,	sepBy_n(npair, SEQ(wel,ws), N))
+	//H_RULE(objstm,	SEQ(ws, osidx, elemr, ws)); -- elemr from array
 
 	/* cross-reference section */
 	H_RULE(xreol,	CHX(SEQ(sp, cr), SEQ(sp, lf), crlf));