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|
;;;; l-system.lisp
#|
(ql:quickload :l-system)
|#
(in-package #:l-system)
;;; "l-system" goes here. Hacks and glory await!
(defun iterconcat (fn list)
"Applies fn on each element of list, and concatenate a copy of the resulting lists."
(iter (for item in list)
(appending (funcall fn item))))
(defun make-case-clause (keys value)
"Make one CASE clause mapping a list of KEYS to one VALUE"
`((,@keys) ',value))
(defun make-case-clauses-from-rules (rules)
"Makes a list of CASE clauses from the RULES."
(mapcar (lambda (rule) (make-case-clause (list (first rule)) (rest rule)))
rules))
(defun generate-l-system (rules)
"Make lambda Lindenmayer system"
`(lambda (atom) (case atom ,@(make-case-clauses-from-rules rules))))
(defmacro l-system (&rest rules)
(generate-l-system rules))
(defun iter-l-system (fn seed n)
(iter (repeat n)
(with item = seed)
(setf item
(iterconcat fn
item))
(finally (return item))))
(defun eval-l-system (fn list)
(iter (with seed = '(0 0 0))
(for item in list)
(appending (setf seed
(mapcar #'+
seed
(car (funcall fn item)))))))
#|
(iterconcat (l-system (a a i a d a)
(b b d b i b)
(i i b i a i)
(d d a d b d))
'(d)) ;; --> (D A D B D)
(iter-l-system (l-system (a a i a d a)
(b b d b i b)
(i i b i a i)
(d d a d b d))
'(d)
3)
;; --> (D A D B D A I A D A D A D B D B D B I B D A D B D A I A D A I B I A I A I A D
A D A D B D A I A D A D A D B D A I A D A D A D B D B D B I B D A D B D B D B
I B D A D B D B D B I B I B I A I B D B I B D A D B D A I A D A D A D B D B D
B I B D A D B D)
(eval-l-system (l-system (a (0.0 1.0 0.0))
(b (0.0 -1.0 0.0))
(i (-1.0 0.0 0.0))
(d (1.0 0.0 0.0)))
(iter-l-system (l-system (a a i a d a)
(b b d b i b)
(i i b i a i)
(d d a d b d))
'(d)
3))
|#
|
