Hi, I wrote lexer return (values (intern "{") (intern "{")) but when using LR parser, the following error occurs. I have red the code expanded by macro, and found that the second argument is evaluated, which should be (intern "{"). If the lexer return (values '{ '{), it works. So is there any way to use string to symbol function in lexer? Thanks, Haiwei Unknown terminal { [Condition of type SIMPLE-ERROR] Restarts: 0: [ABORT] Return to SLIME's top level. 1: [TERMINATE-THREAD] Terminate this thread (#<THREAD "new-repl-thread" {AEFFD89}>) Backtrace: 0: ((LAMBDA (#:G203 #:G205 #:G206)) 6 #<unavailable argument> (0 #<CLOSURE # {AEE11B5}> #<FUNCTION # {AED86B5}> #2A((# # #S(FUCC::ERROR-ACTION) #S(FUCC::ERROR-ACTION) #S(FUCC::ERROR-ACTION) #S(FUCC::ERROR-ACTION) #S(FUCC::ERROR-ACTION) # #S(FUCC::ERROR-ACTION) # ...) (#S(FUCC::ERROR-ACTION) # # # # # # #S(FUCC::ERROR-ACTION) #S(FUCC::ERROR-ACTION) # ...) (#S(FUCC::ACCEPT-ACTION) #S(FUCC::ERROR-ACTION) ..)))) Locals: SB-DEBUG::ARG-0 = 6 SB-DEBUG::ARG-1 = :<NOT-AVAILABLE> SB-DEBUG::ARG-2 = (0 #<CLOSURE (LAMBDA #) {AEE11B5}> #<FUNCTION (LAMBDA #) {AED86B5}>