gui rewritten with builder classes and observables

gui rewritten with builder classes and observables

vmcompact/subject.py

@@ -0,0 +1,32 @@
+class Subject:
+    def __init__(self):
+        """list of current observers"""
+
+        self._observables = []
+
+    def notify(self, modifier=None):
+        """Alert the observers"""
+
+        for observer in self._observables:
+            observer.update()
+
+    def add(self, observer):
+        """adds an observer to observables"""
+
+        if observer not in self._observables:
+            self._observables.append(observer)
+
+    def remove(self, observer):
+        """removes an observer from observables"""
+
+        try:
+            self._observables.remove(observer)
+        except ValueError:
+            pass
+
+    def get(self) -> list:
+        """returns the current observables"""
+        return self._observables
+
+    def clear(self):
+        self._observables.clear()