case func(int) float64:
	printFunction(i)                       // type of i is func(int) float64
case bool, string:
	printString("type is bool or string")  // type of i is type of x (interface{})
default:
	printString("don't know the type")     // type of i is type of x (interface{})
}
</pre>

<p>
could be rewritten:
</p>

<pre>
v := x  // x is evaluated exactly once
if v == nil {

case func(int) float64:
	printFunction(i)                       // type of i is func(int) float64
case bool, string:
	printString("type is bool or string")  // type of i is type of x (interface{})
default:
	printString("don't know the type")     // type of i is type of x (interface{})
}
</pre>

<p>
could be rewritten:
</p>

<pre>
v := x  // x is evaluated exactly once
if v == nil {