when

when conditionally runs its body when the test is True.

Syntax

(when ⟨test⟩
  ⟨expr⟩...)

Semantics

• when is a convenience form for one-sided conditional code for effect.
• Expressions in the body are sequenced as an implicit progn, and the result must unify to Void.
• Use unless for the negated form.

Example

(when verbose?
  (show "starting"))