How to express try catch block in Lisp then ? In all programming language, compo...

tmtvl · on Feb 2, 2023

A try-catch block?

  (handler-case (/ 1 0)
     (division-by-zero (condition)
       (format nil "We caught ~S." condition))
     ((or file-error parse-error type-error) (condition)
      (format nil "We should never catch ~S" condition))
     (:no-error (result)
       (declare (ignore result))
       "We should never get here."))

That's an example of how it can be done in CL, in Scheme you've got guard.

  (guard (con
          ((warning? con)
           "We should never get this.")
          ((assertion-violation? con)
           "We should get this."))
    (/ 1 0))

lispm · on Feb 2, 2023

Common Lisp has a bunch of that stuff. For example HANDLER-CASE

http://www.lispworks.com/documentation/HyperSpec/Body/m_hand...