<mime-type type="application/x-x509-key">
  </mime-type>
  <mime-type type="application/x-x509-key;format=pem">
    <sub-class-of type="application/x-x509-key"/>
    <magic priority="50">
      <match value="-----BEGIN PRIVATE KEY-----" type="string" offset="0"/>
      <match value="-----BEGIN PUBLIC KEY-----" type="string" offset="0"/>
      <match value="-----BEGIN KEY-----" type="string" offset="0"/>

	// type of s is string
	// s == a[i]
	g(i, s)
}

var key string
var val interface{}  // element type of m is assignable to val
m := map[string]int{"mon":0, "tue":1, "wed":2, "thu":3, "fri":4, "sat":5, "sun":6}
for key, val = range m {
	h(key, val)
}
// key == last map key encountered in iteration
// val == map[key]

var ch chan Work = producer()
for w := range ch {
	doWork(w)
}