inside the original alist by using dots inside the symbol, as
displayed in the example above.
+To refer to a non-`let-alist' variable starting with a dot in BODY, use
+two dots instead of one. For example, in the following form `..foo'
+refers to the variable `.foo' bound outside of the `let-alist':
+
+ (let ((.foo 42)) (let-alist \\='((foo . nil)) ..foo))
+
Note that there is no way to differentiate the case where a key
is missing from when it is present, but its value is nil. Thus,
the following form evaluates to nil: