example.flashit

;;caculate distance
(begin
	(define square_sum 
		(lambda (x y)
			(+ (* x x) (* y y))))
	(define distance
		(lambda (x y)
			(sqrt 
				(square_sum 
					(- (px x) (px y)) 
					(- (py x) (py y))))))
	(print 
		(distance 
			(p 1 1)
			(p 0 0)))
)

;;recursive
(begin
	(define fact-sum
		(lambda (x)
			(if (= x 1)
				1
				(+ (self (- x 1))
					((lambda (y)
						(if (= y 1)
							1
							(* y (self (- y 1))))) x)))))
	(print
		(fact-sum 5))
)

;;list
(begin
	(define foo
		(list 1 2))
	(print (++ foo foo 3))
)

;;looper
(define loop
	(lambda (n f)
		(if (= n 0)
			1
			(begin
				(f)
				(self (- n 1) f))))
)

;;static drawing
(begin 
	(place
		(arc
			(p 10 10)
			15
			0
			PI)
		(p 25 25))
	(place 
		(line
			(p 10 10)
			(p 60 60))
		(p 10 10))
	(place
		(circle
			(p 10 10)
			15)
		(p 5 5))
	(draw)
)

;;anime
(begin 
	(define loop
		(lambda (n f)
			(if (= n 0)
				1
				(begin
					(f)
					(self (- n 1) f)))))
	(define futiao
		(g 
			(line (p 10 10) (p 80 80))
			(line (p 10 80) (p 80 10))))
	(define kuang
		(circle (p 45 45) 50))
	(define lunzi
		(g futiao kuang))
	(place lunzi (p 10 10))
	(loop 60
		(lambda ()
			(begin
				(rotate futiao (* PI 0.02))
				(shift lunzi (p 2 0))
				(draw))))
)

;;another example
(begin 
	(define loop
		(lambda (n f)
			(if (= n 0)
				1
				(begin
					(f)
					(self (- n 1) f)))))
	(define x
		(g 
			(line (p 10 10) (p 80 80))
			(line (p 10 80) (p 80 10))))
	(place x (p 10 10))
	(loop 60
		(lambda ()
			(begin
				(rotate x (* PI 0.02) (p 10 10))
				(draw))))
)

;;one more
(begin
	(define rectangle
		(lambda (a b x y)
			(g
				(line (p x y)
					(p (+ x a) y))
				(line (p x (+ y b))
					(p (+ x a) (+ y b)))
				(line (p x y)
					(p x (+ y b)))
				(line (p (+ x a) y)
					(p (+ x a) (+ y b))))))
	(define loop
		(lambda (n f)
			(if (= n 0)
				1
				(begin
					(f)
					(self (- n 1) f)))))
	(define left
		(rectangle 20 20 20 20))
	(define right
		(rectangle 20 20 50 20))
	(define both
		(g left right))
	(place both (p 0 0))
	(draw)
	(loop 20
		(lambda ()
			(begin
				(shift left (p 0 1))
				(shift right (p 1 0))
				(draw))))
	(erase both)
	(draw)
)

;;a cross shifting
(begin
	(define cross 
		(g
			(line (p 0 0)
				(p 50 50))
			(line (p 50 0)
				(p 0 50))
			(circle (p 25 25) (* 25 (sqrt 2)))))
	(define loop
		(lambda (n f)
			(if (= n 0)
				1
				(begin
					(f)
					(draw)
					(self (- n 1) f)))))
 	(place cross (p 0 0))
 	(loop 100 (lambda () (shift cross (p 1 1))))
 	(erase cross)
 	(draw)
)