+(export 'parse-empty)
+(defun parse-empty (&optional value)
+ "Return a parser which parses nothing, successfully.
+
+ The parser returns VALUE and consumes nothing."
+ (lambda () (values value t nil)))
+
+(export 'parse-fail)
+(defun parse-fail (indicator &optional consumedp)
+ "Return a parser which fails.
+
+ The parser reports the INDICATOR and (falsely) claims to have consumed
+ input if CONSUMEDP is true."
+ (lambda () (values indicator nil consumedp)))
+