compile/if

Syntax: (if COND THEN ELSE), (if COND then: THEN else: ELSE), or (if COND THEN), whose else arm is None.

Behaviour: Expands to (cond [COND THEN] [else: ELSE]). The layout form if ...: with elif and else peers reads directly to cond through layout/if, so a multi-line if never passes through this macro.

Examples:

(if (< n 0) "negative" "non-negative")
(if ready then: (go) else: (wait))
(if ready (go))                  ;; None when not ready

>>> (macroexpand-1 '(if a then: b else: c))
(cond [a b] [else: c])

See also: cond, when, ?.

Also: layout handler if.