ijp · March 29, 2015 14:55 · Mar 29, 2015
diff --git a/parameters.py b/parameters.py
@@ -0,0 +1,40 @@
+# a sketch of how Scheme fluids/parameters would work in python
+
+obarray = {}
+
+class Manager(object):
+    def __init__(self, parameter, value):
+        self.parameter = parameter
+        self.value = value
+
+    def __enter__(self):
+        self.old_value = self.parameter.get()
+        obarray[self.parameter] = self.value
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        ## A real pro would handle exceptions
+        obarray[self.parameter] = self.old_value
+
+class Parameter(object):
+    def __init__(self, value):
+        obarray[self] = value
+
+    def get(self):
+        return obarray[self]
+
+    def __call__(self, new_value):
+        return Manager(self, new_value)
+
+current_foo = Parameter(10)
+
+print "1", current_foo.get()
+
+with current_foo(20):
+    print "2", current_foo.get()
+
+    with current_foo(30):
+        print "3", current_foo.get()
+
+    print "2", current_foo.get()
+
+print "1", current_foo.get()