diff options
Diffstat (limited to 'src/utils.lisp')
| -rw-r--r-- | src/utils.lisp | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/src/utils.lisp b/src/utils.lisp index bcb4cb2..ed7be38 100644 --- a/src/utils.lisp +++ b/src/utils.lisp @@ -103,3 +103,27 @@ the path." :width (- max-x min-x) :height (- max-y min-y))))) +(defmacro setf-many (places-and-value) + "e.g. (setf-many a b c 10) would set a b and c to 10" + (let ((value-form + (first (last places-and-value)))) + `(setf ,@(butlast places-and-value) ,value-form))) + + +(defmacro with-line + ((x y) (start-x start-y) (end-x end-y) &body body) + "Execute BODY for X and Y assigned to integer values in a line +connecting the integer point START-X , START-Y and END-X, END-Y. " + (with-gensyms (sx sy ex ey distance step progress xdiff ydiff) + `(let* ((,sx ,start-x) + (,sy ,start-y) + (,ex ,end-x) + (,ey ,end-y) + (,xdiff (- ,ex ,sx)) + (,ydiff (- ,ey ,sy)) + (,distance (max (abs ,xdiff) (abs ,ydiff)))) + (loop for ,step from 0 to ,distance + for ,progress = (if (zerop ,distance) 0.0 (/ ,step ,distance)) + for ,x = (round (+ ,start-x (* ,progress ,xdiff))) + for ,y = (round (+ ,start-y (* ,progress ,ydiff))) + do (progn ,@body))))) |