L-System stuff

lsystem.py

import turtle, random
from lsystemconfig import *

stack = []

def iterateLSystem(system, rule):
	mutatedLSystem = ""
	for char in system:
		charAccountedFor = False
		for oneRule in rule:
			if oneRule[0] == char:
				mutatedLSystem += oneRule[1]
				charAccountedFor = True 
		if not charAccountedFor:
			mutatedLSystem += char
	return mutatedLSystem 

def moveTurtle(instruction):
	if instruction == '+':
		turtle.left(ANGLE)
	elif instruction == '-':
		turtle.right(ANGLE)
	elif instruction == '[':
		stack.append((turtle.position(), turtle.heading()))
	elif instruction == ']':
		turtle.penup()
		turtleInfo = stack.pop()
		turtle.goto(turtleInfo[0])
		turtle.setheading(turtleInfo[1])
		turtle.pendown()
	elif instruction == '?':
		turtle.setheading(random.randint(0, 360) * ANGLE)
	elif instruction == '!':
		if random.choice([True, False]):
			turtle.left(ANGLE)
		else:
			turtle.right(ANGLE)
	elif (not (instruction in CONSTANTS)):
		turtle.forward(LENGTH)

def saveImage(name):
	ts = turtle.getscreen()
	ts.getcanvas().postscript(file = name + ".eps")

if __name__ == "__main__":
	turtle.speed(0)
	turtle.tracer(10000, 0)
	#for ang in range(360):
	turtle.hideturtle()
	#ANGLE = ang + 1
	iterations = [AXIOM]
	for i in range(MAX_ITERATIONS):
		iterations.append(iterateLSystem(iterations[-1], RULE)) #apply the function to the last element of the list and repeat
	print iterations[-1]
	turtle.penup()
	turtle.screensize(5000, 5000)
	turtle.setup(width = 1600, height = 900, startx = 0, starty = 0)
	#turtle.goto((turtle.screensize()[0])/-2, (turtle.screensize()[1])/-2)
	turtle.pendown()
	for instruction in iterations[-1]: #actually draw it now
		moveTurtle(instruction)
	turtle.done()
	#saveImage(str(ANGLE))
	#turtle.reset()

lsystemconfig.py

MAX_ITERATIONS = 5
AXIOM = "F"
CONSTANTS = ""
RULE = [('F', "FF-[-F+F+F]+[+F-F-F]")]
ANGLE = 22
LENGTH = 5