Added additional 'add' support to OpenSCADObjects

Oliver Robson · Oliver Robson · commit 4ea553cfba2b · 2018-03-16T16:45:07.000+11:00
* Added support for __radd__
  * Functions as per __add__
* Added support for adding ints
  * ValueErrors if not 0
  * Adding an OpenSCADObject and 0 just returns the OpenSCADObject

These changes allow for the use of sum() on OpenSCADOBject lists
diff --git a/solid/solidpython.py b/solid/solidpython.py
@@ -475,6 +475,10 @@ def add(self, child):
             if len(child) == 1 and isinstance(child[0], (list, tuple)):
                 child = child[0]
             [self.add(c) for c in child]
+        elif isinstance(child, int):
+            # Allowing for creating object by adding to 0 (as in sum())
+            if child != 0:
+                raise ValueError
         else:
             self.children.append(child)
             child.set_parent(self)
@@ -531,6 +535,13 @@ def __add__(self, x):
         '''
         return objects.union()(self, x)
 
+    def __radd__(self, x):
+        '''
+        This makes u = a+b identical to:
+        u = union()(a, b )
+        '''
+        return objects.union()(self, x)
+
     def __sub__(self, x):
         '''
         This makes u = a - b identical to:
