Make defsketch generate a function for running sketches.

README.org

@@ -88,13 +88,14 @@ If you did everything correctly, you should be able to =(ql:quickload :sketch)=
 
 #+BEGIN_SRC lisp
 CL-USER> (ql:quickload :sketch-examples)
-CL-USER> (make-instance 'sketch-examples:hello-world)
-CL-USER> (make-instance 'sketch-examples:sinewave)
-CL-USER> (make-instance 'sketch-examples:brownian)
-CL-USER> (make-instance 'sketch-examples:life) ; Click to toggle cells,
-                                               ; any key to toggle iteration
-CL-USER> (make-instance 'sketch-examples:input)
-CL-USER> (make-instance 'sketch-examples:stars)
+CL-USER> (in-package sketch-examples)
+SKETCH-EXAMPLES> (run-hello-world)
+SKETCH-EXAMPLES> (run-sinewave)
+SKETCH-EXAMPLES> (run-brownian)
+SKETCH-EXAMPLES> (run-life) ; Click to toggle cells,
+                            ; any key to toggle iteration
+SKETCH-EXAMPLES> (run-input)
+SKETCH-EXAMPLES> (run-stars)
 #+END_SRC
 
 *** Running example code from this page
@@ -108,11 +109,11 @@ TUTORIAL> ;; ready
 #+END_SRC
 
 ** Tutorial
-Defining sketches is done with the =defsketch= macro, which is essentially a wrapper for =defclass=.
+Defining sketches is done with the =defsketch= macro. This defines a function called `run-NAMEHERE` for starting your sketch. Alternatively, you can do `(run-sketch 'NAMEHERE)`.
 
 #+BEGIN_SRC lisp
   (defsketch tutorial ())
-  (make-instance 'tutorial)
+  (run-tutorial)
 #+END_SRC
 
 If all goes well, this should give you an unremarkable gray window. From now on, assuming you're using Emacs + SLIME, or a similarly capable environment, you can just re-evaluate =(defsketch tutorial () <insert drawing code here>)= and the sketch will be restarted without you having to close the window or make another instance of the class.

src/package.lisp

@@ -15,6 +15,7 @@
            :draw
 
            :defsketch
+           :run-sketch
 
            :sketch-title
            :sketch-width

src/sketch.lisp

@@ -315,6 +315,15 @@
                    collect `(,(binding-accessor b) *sketch*)
                    collect (binding-name b)))))
 
+(defun define-sketch-run-function (name bindings)
+  `(defun ,(alexandria:symbolicate 'run- name)
+       (&rest args
+          &key ,@(loop for b in bindings
+                        collect (list (binding-name b) (binding-initform b)))
+        &allow-other-keys)
+     (declare (ignore ,@(loop for b in bindings collect (binding-name b))))
+     (apply #'make-instance ',name args)))
+
 (defmacro defsketch (sketch-name binding-forms &body body)
   (let ((bindings (parse-bindings sketch-name binding-forms
                                   (class-bindings (find-class 'sketch)))))
@@ -323,10 +332,18 @@
        ,@(define-sketch-channel-observers bindings)
        ,(define-sketch-prepare-method sketch-name bindings)
        ,(define-sketch-draw-method sketch-name bindings body)
+       ,(define-sketch-run-function sketch-name bindings)
 
        (make-instances-obsolete ',sketch-name)
        (find-class ',sketch-name))))
 
+(defun run-sketch (name &rest args)
+  (let ((cls (find-class name nil)))
+    (when (or (null cls)
+              (not (c2mop:subclassp cls (find-class 'sketch))))
+      (error (format nil "Couldn't find a sketch called ~a" name)))
+    (apply #'make-instance name args)))
+
 ;;; Control flow
 
 (defun stop-loop ()