diff --git a/lex.dd b/lex.dd
index ea2d8b7e7f..1c56647765 100644
--- a/lex.dd
+++ b/lex.dd
@@ -60,10 +60,13 @@ $(H3 Source Text)
 	technique, i.e., the
 	lexical analyzer tries to make the longest token it can. For example
 	$(D >>) is a right shift token,
-	not two greater than tokens. An exception to this rule is that a $(D ..)
-	embedded inside what looks like two floating point literals, as in
-	$(D 1..2), is interpreted as if the $(D ..) was separated by a space from the
-	first integer.
+	not two greater than tokens. There are two exceptions to this rule:
+	$(UL
+		$(LI A $(D ..) embedded inside what looks like two floating point
+		literals, as in $(D 1..2), is interpreted as if the $(D ..) was
+		separated by a space from the first integer.)
+		$(LI A $(D 1.a) is interpreted as the three tokens $(D 1), $(D .), and $(D a),
+		while $(D 1. a) is interpreted as the two tokens $(D 1.) and $(D a))
 	)
 
 $(H3 Character Set)