(if condition then else) condition: any form then: any form else: any form
S
Performs conditional evaluation.
First, the condition form is evaluated. If it evaluates to #f or #n, the else
form is evaluated; otherwise, the then form is evaluated.
This form is rarely used directly. cond, when and unless
are usually more readable.
if is sometimes useful when you want to express a very short conditional which fits on
a single line:
(= color (if (< hp 10) 'red 'green))