Rust on BBC micro:bit
This is by now a familiar sight:<p><pre><code>  #[lang = "eh_personality"] extern fn eh_personality() {}
  #[lang = "panic_fmt"] extern fn panic_fmt() -> ! { loop {} }
</code></pre>
But it's a little unsatisfying.<p>What does eh_personality actually do, and how would you write a 'real' implementation?<p>I can guess what panic_fmt is for, but exactly what is it supposed to do, and how would you write a 'real' implementation?