;;; -*- mode: lisp; syntax: common-lisp; package: existenz-client; coding: utf-8-unix; -*-

(in-package #:existenz-common)

;;; shorthand for interactive degree values, also coerces to
;;; CL-TUPLES::FAST-FLOAT

(defun to-radian (degree)
  (* degree #.(coerce (/ pi 180) 'cl-tuples::fast-float)))

;; FIXME: this fails omniusly while reading NIL
#+(or)
(defun |#°-reader| (stream sub-char arg)
  (declare (ignore sub-char arg))
  (let ((read (read stream T NIL T)))
    (and read (to-radian read))))

;; (set-dispatch-macro-character #\# #\° #'|#°-reader|)

(defun matrix-elements (dimensions &optional (prefix '#:e))
  (labels ((aux (dimensions)
             (let ((car (car dimensions))
                   (cdr (cdr dimensions)))
               (if cdr
                   (iterate outer
                     (for i from 0 below car)
                     (iterate
                       (for x in (aux cdr))
                       (in outer (collect (list* i x)))))
                   (iterate
                     (for i from 0 below car)
                     (collect (list i)))))))
    (map 'list (lambda (list)
                 (find-symbol (format NIL "~A~{~A~}" prefix list)))
         (aux dimensions))))

(defun matrix2-elements (dimension &optional (prefix '#:e))
  (matrix-elements (list dimension dimension) prefix))