gistfile1.txt

; for every line produced as in run-buffer in 
; https://bitbucket.org/vityok/cl-faster-input/src/default/src/benchmark-read-line.lisp
; do this:

(defun proc-line (l)
  (with-input-from-string (in l)
    (let ((vals (loop for x = (read in nil nil) while x 
                      collect (coerce x 'double-float))))
      (values (vec:3vec* (subseq vals 0 3))
              (apply #'pigment:rgb (append (mapcar (lambda (v) (/ v 255d0))
                                             (subseq vals 4)) (list 0.3d0)))))))

; about twice as fast as my initial approach

; current run-buffer looks like this:

(defun run-buffer (fn fx &key (buffer-width 80))
  (let ((buffer (make-array buffer-width
                            :element-type 'character
                            :initial-element #\space))
        (lines 0))
    (with-open-file (is fn :direction :input)
      (loop for (val pos newl) =
                  (multiple-value-list (read-line-into-sequence buffer is
                                         :eof-error-p nil))
            while val
            do ; subseq here is probably a bad idea because it reallocates a string?
               (when newl (funcall fx (subseq val 0 pos)))
               (incf lines)))))

(defun proc-line (l)
  (let ((vals (with-input-from-string (in l)
                (let ((*read-default-float-format* 'double-float))
                  (loop for x = (read in nil nil) while x 
                        collect x)))))
    (values (vec:3vec* (subseq vals 0 3))
            (apply #'pigment:rgb (nconc (mapcar (lambda (v) (/ v 255d0))
                                                 (subseq vals 4))
                                         (list 0.3d0))))))

or even

(defun proc-line (l)
  (multiple-value-bind (l0 l1)
      (with-input-from-string (in l)
        (let ((*read-default-float-format* 'double-float))
          (loop for x = (read in nil nil)
                for i from 0
                while x
                if (< i 3)
                collect x into l0
                else collect (/ x 255d0) into l1
                finally (return (values l0 l1)))))
    (values (vec:3vec* l0)
            (apply #'pigment:rgb (nconc l1 (list 0.3d0))))))