49 lines
652 B
Plaintext
49 lines
652 B
Plaintext
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& Example 2: fractal (binary) tree
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& from https://en.wikipedia.org/wiki/L-system
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box states = []
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fn push! () -> {
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update! (states, append (_, turtle_state ()))
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}
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fn pop! () -> {
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let state = do states > unbox > last
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update! (states, butlast)
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penup! ()
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load_turtle_state! (state)
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}
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fn branch! () -> {
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pc! (colors :olive)
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pw! (4)
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fd! (20)
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}
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fn one! {
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(0) -> {
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branch! ()
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}
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(n) -> {
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one! (dec (n))
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one! (dec (n))
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}
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}
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fn zero! {
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(0) -> branch! ()
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(n) -> {
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one! (dec (n))
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push! ()
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lt! (inv (10))
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zero! (dec (n))
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pop! ()
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rt! (inv (10))
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zero! (dec (n))
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}
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}
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zero! (7)
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hideturtle! ()
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