CL-USER 1 > (defun add3 (x) (check-type x number) (+ x 3))

ADD3

 

CL-USER 2 > (add3 'seven)

 

Error: The value SEVEN of X is not of type NUMBER.

  1 (continue) Supply a new value of X.

  2 (abort) Return to level 0.

  3 Return to top loop level 0.

 

Type :b for backtrace or :c <option number> to proceed.

Type :bug-form "<subject>" for a bug report template or :? for other options.

 

CL-USER 3 : 1 > :c 1

 

Enter a form to be evaluated: 3

 

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