L-Systems 0.0.2

from turtle import *


axiomA='A'
rulesA = {}
rulesA['A'] = 'AB'
rulesA['B'] = 'A'

axiomB='B'
rulesB = {}
rulesB['B'] = 'BA'
rulesB['A'] = 'B'

axiomF='F'
rulesF = {}
rulesF['F'] = 'F+F-F-F+F'


def compose(axiom, rules):
        output = ""
        for i in axiom:
            output = output + rules.get(i,i)
        return output

def iterate(axiom,rules, times):
    output = ''
    if times == 0:
        output = axiom
    else:
        return iterate(compose(axiom, rules), rules, times -1)
    return output

print iterate(axiomA,rulesB,6)
print iterate(axiomB,rulesA,6)
directions = iterate(axiomF,rulesF,3)
print directions

color('red','yellow')
begin_fill()
for words in directions:
    if words == 'F':
        forward(10)
    elif words == '+':
        left(90)
    elif words == '-':
        right(90)

end_fill()
done()

#special thanks to http://www.4dsolutions.net/ocn/lsystems.html