You must have a client app running that can be communicated with and that
you're trying to modify; otherwise driver.love will hang until it finds one,
and might need to be force-quit. (Also, bad things will happen if you have
_more than a single_ client app running. Or if you close one app and open
another without restarting the driver. Just always open the app and then the
driver. If you close the app, close the driver.)

You must have a ["freewheeling"](http://akkartik.name/post/roundup22) client
app running that can be communicated with and that you're trying to modify;
otherwise driver.love will hang until it finds one, and might need to be
force-quit. (Also, bad things will happen if you have _more than a single_
client app running. Or if you close one app and open another without
restarting the driver. Just always open the app and then the driver. If you
close the app, close the driver.)

Each definition lives in a blue box. You have to follow a specific Lua syntax
where the name of the definition comes first: `foo = function(...) ... end`
rather than `function foo(...) ... end`. The driver treats the first word in a
definition is its name.
Functions that start with `test_` are tests, and run any time you hit `f4`.
The driver will highlight them in green or red when they fail.

* `f4` to send current buffer to some app. (Run only one such live app at a
  time.)

* `f4` to send current buffer to the client app. (Run only one such
  "freewheeling" app at a time.)

* You have to follow a specific Lua syntax where the name of the definition
  comes first: `foo = function(...) ... end` rather than `function foo(...)
  ... end`. The driver treats the first word in a definition is its name. For
  similar reasons, a definition can't start with a comment. Put comments
  within functions or after them.