Assertions are a way of breaking out of code when there is an error or an unexpected input.

Some languages throw exceptions and some treat it as a break point.



Task

Show an assertion in your language by asserting that an integer variable is equal to 42.




 
(assert (integer? 42)) → #t ;; success returns true
 
;; error and return to top level if not true;
(assert (integer? 'quarante-deux))
⛔ error: assert : assertion failed : (#integer? 'quarante-deux)
 
;; assertion with message (optional)
(assert (integer? 'quarante-deux) "☝️ expression must evaluate to the integer 42")
💥 error: ☝️ expression must evaluate to the integer 42 : assertion failed : (#integer? 'quarante-deux)
 