id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	difficulty
940	Cannot unset read syntax	megane		"This error only shows up with the interpreter.

I've attached a patch.

{{{
(set-read-syntax!
 #\!
 (lambda (port) 
   (read-string 3 port)))

(print (string? !foo))

(set-read-syntax! #\! #f) ; <- try to unset
(print ""here"")
(print (string? !foo))

;; ; loading bug.scm ...
;; #t
;; here

;; Error: call of non-procedure: #f

;; 	Call history:

;; 	parley.scm:587: set-port-name!	  
;; 	<syntax>	  (set-read-syntax! #\! (lambda (port) (read-string 3 port)))
;; 	<syntax>	  (lambda (port) (read-string 3 port))
;; 	<syntax>	  (##core#lambda (port) (read-string 3 port))
;; 	<syntax>	  (##core#begin (read-string 3 port))
;; 	<syntax>	  (read-string 3 port)
;; 	<eval>	  (set-read-syntax! #\! (lambda (port) (read-string 3 port)))
;; 	<eval>	  (read-string 3 port)
;; 	<syntax>	  (print (string? ""foo""))
;; 	<syntax>	  (string? ""foo"")
;; 	<eval>	  (print (string? ""foo""))
;; 	<eval>	  (string? ""foo"")
;; 	<syntax>	  (set-read-syntax! #\! #f)
;; 	<eval>	  (set-read-syntax! #\! #f)
;; 	<syntax>	  (print ""here"")
;; 	<eval>	  (print ""here"")	<--
}}}
"	defect	closed	minor	someday	unknown	4.8.x	fixed