Racket

Assorted primitives

(define CONSTANT "value") ; constant definition
 
(check-expect (aspect-ratio CONSTANT) true) ; like assert in Python
 
(define (aspect-ratio argument) ; function definition
	(if (> (image-height img) (image-width img)) ; operators and if/else
		"tall"
		(if (= (image-height img) (image-width img))
		"square"
		"wide)))

Using cond to avopid nested if/else. More like if/elseif.

(define (aspect-ratio img)
	(cond [(> (image-height img) (image-width img)) "tall"] ; note that in Racket () and [] are equivalent
		  [(= (image-height img) (image-width img) "square"]
		  [else "wide"])) ; "else" is optional, it can be another condition.

Data definitions