Add a macro to display a progress indicator to looping process

src/utils.lisp

@@ -11,6 +11,7 @@
            :safe-first :safe-list
            :group
            :restartable
+           :loop-with-progress
            :add-hook :remove-hook :run-hook
            :update-current-time :get-delta-time
            :make-clock :clock-time :clock-delta
@@ -63,6 +64,20 @@
             ,@body)
         (continue () :report "Continue"))))
 
+(defmacro loop-with-progress (msg &body body)
+  "Allow a looping process to display feedback."
+  `(macrolet ((progress-step ()
+                `(progn
+                   (when (> progress-index progress-max-columns)
+                     (format t "~%")
+                     (setf progress-index 0))
+                   (format t "."))))
+     (let ((progress-max-columns 80))
+       (format t ,msg)
+       (loop for progress-index upfrom ,(length msg)
+            ,@body)
+       (format t "~%"))))
+
 (defmacro add-hook (hook fun &optional append)
   "Setup `fun' to be called within specified `hook'."
   `(unless (member ,fun ,hook)