diff --git a/src/structs.h b/src/structs.h
index 884d6a9..aa93aae 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -979,9 +979,10 @@
 struct mapblock
 {
     mapblock_T	*m_next;	/* next mapblock in list */
-    char_u	*m_keys;	/* mapped from */
+    char_u	*m_keys;	/* mapped from, lhs */
     int		m_keylen;	/* strlen(m_keys) */
-    char_u	*m_str;		/* mapped to */
+    char_u	*m_str;		/* mapped to, rhs */
+    char_u	*m_orig_str;	/* rhs as entered by the user */
     int		m_mode;		/* valid mode */
     int		m_noremap;	/* if non-zero no re-mapping for m_str */
     char	m_silent;	/* <silent> used, don't echo commands */