Re: Using the GNU GMP Library for Bignums in Emacs

[Richard Stallman]

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  > We already have such a feature. For example, (format "%09x" 257) returns
  > "000000101", which is 257 hexadecimal, expressed using leading zeros as 
needed 
  > so that at least 9 digits are used. Once Emacs supports bignums, the same 
  > feature can print 40-hex-digit SHA-1 checksums by using (format "%040x" n).

Perhaps this way everything would work with all-positive hex numbers.

However, I think we also want a feature to signal an error if the
number doesn't fall in the range that the %x construct can represent.
If the Git hash code is 40 hex digits, any attempt to use as a Git hash code
a number that won't fit in 40 hex digits implies that there has already been
an error.

I suggest %!040x for this.  The ! would mean, "Signal an error if the number
doesn't fit in the specified number of digits."  It could be implemented
for all %-specs, but if that is a pain in the neck, it could be implemented
only for %x.


-- 
Dr Richard Stallman
President, Free Software Foundation (https://gnu.org, https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)
Skype: No way! See https://stallman.org/skype.html.