Add functions for window creation

engine/core.scm

@@ -339,5 +339,32 @@
   (with-drawing
    execute-systems))
 
+;; Utility function for guarding parameter values
+(define (guarded-parameter default predicate)
+  (make-parameter default (lambda (val)
+			    (if (predicate val)
+				val
+				default))))
 
+;; Window creation
+(export *window-size* *window-title* create-window)
+
+;; Window size to use
+(define *window-size* (guarded-parameter '(768 . 576)
+					 (lambda (x)
+					   (and (pair? x)
+						(integer? (car x))
+						(integer? (cdr x))))))
+
+;; Window title
+(define *window-title* (guarded-parameter "imugi"
+					  string?))
+
+(define (create-window #!key (process next-frame) (close-predicate window-should-close?))
+  (init-window (car (*window-size*)) (cdr (*window-size*)) (*window-title*))
+  (let loop ()
+    (process)
+    (unless (close-predicate)
+      (loop)))
+  (close-window))
 )