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kflak's questions

Martin Hope
kflak
Asked: 2024-12-29 02:13:31 +0800 CST
  • 5

给定一个类定义，是否可以根据另一个插槽来定义一个插槽，类似于我如何做的let*？

例如，我希望能够做这样的事情（显然不起作用）：

(defclass foo ()
  ((x :initform 1 :accessor x)
   (y :initform (+ 1 x) :accessor y)))
common-lisp
Martin Hope
kflak
Asked: 2024-11-19 13:24:43 +0800 CST
  • 6

我正在尝试编写一个时间线生成器，它采用包含要执行的时间和函数的 plist：

(defun run-timeline (timeline)
  "Timeline is a plist with alternating timecodes and code to execute"
  (alexandria:doplist (time form timeline)
    (sb-ext:schedule-timer
     (sb-ext:make-timer form
                        :thread t)
     time)))

(run-timeline '(0 (print "first")
                    2 (print "second")))

然而，这给了我这个错误：

The value
  (PRINT "first")
is not of type
  (OR FUNCTION SYMBOL)
   [Condition of type TYPE-ERROR]

Restarts:
 0: [USE-VALUE] Use specified value.
 1: [ABORT] abort thread (#<THREAD tid=203285 "Timer NIL" RUNNING {1001179523}>)

Backtrace:
 0: (SB-VM::CALL-SYMBOL)
 1: ((FLET SB-THREAD::WITH-RECURSIVE-LOCK-THUNK :IN SB-IMPL::MAKE-CANCELLABLE-INTERRUPTOR))
 2: ((FLET "WITHOUT-INTERRUPTS-BODY-" :IN SB-THREAD::CALL-WITH-RECURSIVE-LOCK))
 3: ((FLET "WITHOUT-INTERRUPTS-BODY-1" :IN SB-IMPL::MAKE-CANCELLABLE-INTERRUPTOR))
 4: ((LAMBDA NIL :IN SB-IMPL::MAKE-CANCELLABLE-INTERRUPTOR))
 5: ((FLET SB-UNIX::BODY :IN SB-THREAD::RUN))
 6: ((FLET "WITHOUT-INTERRUPTS-BODY-" :IN SB-THREAD::RUN))
 7: ((FLET SB-UNIX::BODY :IN SB-THREAD::RUN))
 8: ((FLET "WITHOUT-INTERRUPTS-BODY-" :IN SB-THREAD::RUN))
 9: (SB-THREAD::RUN)
10: ("foreign function: call_into_lisp_")

当对 lambda 表达式进行硬编码时，我没有收到任何错误，并且它按预期工作：

(defun run-timeline (timeline)
  "Timeline is a plist with alternating timecodes and code to execute"
  (alexandria:doplist (time form timeline)
    (sb-ext:schedule-timer
     (sb-ext:make-timer (lambda ()
                          (print "hi")
                          (force-output))
                        :thread t)
     time)))

我在这里遗漏了什么？

common-lisp