title: Where is the from_char() function for integer types?
body: <p>The char type has <a href="http://doc.rust-lang.org/nightly/core/char/fn.from_digit.html" rel="noreferrer"><code>from_digit()</code></a> and <a href="http://doc.rust-lang.org/nightly/core/char/fn.from_u32.html" rel="noreferrer"><code>from_u32()</code></a> for getting a char from a digit or from a <code>u32</code>, but where are the converse functions for the integer types (all of them)?</p>
  
  <p>i.e. I expected to see some uN::from_{char|digit}() and iN::from_{char|digit}() functions (where N is 8, 16, 32, 64 or size) for symmetry but apparently they do not exist.</p>