jamesarosen/ember-cpm — pull request #50 by TrueNorth (2014-10-06 07:49:37+00:00)
Title: Sum (Addition)

Similar to #48, in that it supports composable macros

```js
MyType = Ember.Object.extend({
d: sum('a', 'b'),
e: sum('a', 'b', 'c'),
f: sum('a', 'b', 'c', 2),
g: sum('a'),
h: sum(2),
i: sum(),
j: [1, 2, 3, 4],
k: sum(Ember.computed.max('j'), 5),
l: sum(sum('a', 'b'), 5),
});
```