snarez/calculon — pull request #29 by richo (2014-02-05 01:41:41+00:00)
Title: Features/sweet watch syntax

Lets you do:

```
>>> watch a + 15
```

Or with voltron for example:

```
>>> watch V.rip
```

The issue is that if you watch a variable that doesn't exist it NameErrors into oblivion. Not sure if that's a bug. Maybe we should call the expr once to see if it works and refuse to add it if the world explodes?