define-exception declares an exception type that can be constructed and signaled with throw.

Syntax

(define-exception ⟨name⟩
  ⟨constructor⟩...)

;; ⟨constructor⟩ := ⟨constructor-name⟩
;;                | (⟨constructor-name⟩ ⟨arg-type⟩ ...)

Semantics

  • define-exception is a toplevel definition form.
  • Its constructor syntax matches define-type closely, including optional docstrings on the type and constructors.
  • Exception types do not accept type variables.
  • Exception constructors are ordinary constructors and can be created outside throw.

Example

(define-exception BadEgg
  (UnCracked Egg)
  (DeadlyEgg Egg))