diff --git a/include/sexpr/sexp.h b/include/sexpr/sexp.h
index 2359af6..7f6a0fc 100644
--- a/include/sexpr/sexp.h
+++ b/include/sexpr/sexp.h
@@ -569,11 +569,11 @@ typedef struct sexp_iowrap {
 
 /* TODO: doxygen? more doxygen */
 typedef struct sexp_cstrwrap {
-  pcont_t *cc;
-  const char *seval;
+  pcont_t *cc; /* continuation used to parse */
+  const char *seval; /* pointer used to the original piece */
   size_t rl, cnt;
   size_t sln;
-  char buf[CSTRBUFSIZ];
+  char buf[CSTRBUFSIZ]; /* internal buffer */
 } sexp_cstrwrap_t;
 
 /*========*/