+;;; Engine Properties
+
+(define* (get-property property-path #:key (engine (current-engine)))
+ (let ((entities (get-entities-by-components (list (car property-path)) #:engine engine)))
+ (cond ((null? entities)
+ #f)
+ (else
+ (let loop ((property (get-component (car property-path) (car entities)))
+ (path (cdr property-path)))
+ (cond ((or (null? path) (not property))
+ property)
+ (else
+ (loop (assoc-ref property (car path)) (cdr path)))))))))
+
+(define* (set-property! property-path value #:key (engine (current-engine)))
+ (define (loop property path)
+ (cond ((null? path)
+ value)
+ (else
+ (assoc-set! (or property '()) (car path) (loop (assoc-ref property (car path)) (cdr path))))))
+
+ (let ((entities (get-entities-by-components (list (car property-path)) #:engine engine)))
+ (cond ((null? entities)
+ (new-entity! `(,(car property-path) . ,(loop '() (cdr property-path)))))
+ (else
+ (set-entity-components! (get-key (car entities)) `(,(car property-path) . ,(loop (get-component (car property-path) (car entities)) (cdr property-path))))))))
+
+(export get-property
+ set-property!)
+
+
+;;; Engine Inner Properties
+
+(define (default-step) 0.1)
+
+(define (default-engine-inner-properties)
+ `(engine-inner-properties (step . ,(default-step))))
+
+