2012/2/25 Yusuke Endoh <mame / tsg.ne.jp>:

> I agree with akr; Martin's proposal depends on the type long, which
> is not "portable" enough.  For designing the APIs, I think we should
> refer gmplib, which is a giant in this area.
>
> http://gmplib.org/manual/Integer-Import-and-Export.html

At first time I see that, I guess there is no application of "nails" argument.

Now I think I know several applications:

* Integer#to_s(radix) for radix is power of 2
  For example, i.to_s(2) can be implemented using that with size=1 and
nails=7 and
  0 and 1 are converted to '0' and '1' later.

* BER-compressed integer for pack (size=1 and nails=1)
-- 
Tanaka Akira