Self invoking Coffeescript 

```
$ -> 
  alert "Hello CoffeeScript!"

```

Compiles to 

```
$(function() {
  return alert("Hello CoffeeScript!");
});

```

Now, the same code -- $ replaced with any other variable -->

```
hello= -> 
  alert "Hello CoffeeScript!"

```

Above code - Does not execute by itself. 

**How does giving a `$` variable enable self execution(jQuery lib not included)?** (is jQuery is playing a role here?) 

I know you've to use `do` to have self invoking functions in `coffeescript` --- that's not my question ( please do not duplicate it ).

-coffeescript beginner