turtle

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turtle


Definition:

run "geomland

make [domain] "turtle

to turtle
	local  "pos  "ang  "pen  "col  "showit  "shape

	to home
		make "pos point 0 0
		make "ang 90
		make "pen "true
		make "col :black
		make "showit "true
		image
	end

	to image
		if :showit
		[
			make "shape triangle :pos :ang
		]
	end

	to forward :dist

		make local "newpos :pos + (point :dist 0) ° :ang
		if :pen 
		[
			make "turtle_seg segment :pos :newpos
			make "turtle_seg.color :col
			traced "turtle_seg
			repaint
			delete "turtle_seg
		]
		make "pos :newpos
		image
	end

	to fd :dist
		forward :dist 
	end

	to back :dist
		forward (-:dist)
	end

	to bk :dist
		back :dist
	end

	to left :a
		make "ang :ang+:a
		image
	end

	to lt :a
		left :a
	end

	to right :a
		make "ang :ang-:a
		image
	end

	to rt :a
		right :a
	end

	to show
		make "showit "true
		image
		repaint
	end

	to hide
		delete "shape
		make "showit "false
		image
		repaint
	end

	to color :x
		make "col :x
		image
	end

	to penup
		make "pen "false
	end

	to pu 
		penup 
	end

	to pendown
		make "pen "true
	end

	to pd 
		pendown 
	end

	to setx :x
		make "pos.x :x
	end

	to sety :y
		make "pos.y :y
	end

	to setxy :x :y

		make local "newpos (point :x :y)

		if :pen 
		[
			make "turtle_seg segment :pos :newpos
			make "turtle_seg.color :col
			traced "turtle_seg
			repaint
			delete "turtle_seg
		]
		make "pos :newpos
		image
	end

	to ondrawimage 
	end

	home
end

Here`s a first simple example:

run "turtle

setxy -50 -50
color green
repeat 4
[
	fd 100
	rt 90
]
hide
left 44
fd 100
wait 1
show
home

Examples:

References:

Turtle Graphics home