:
s/[1-9]#*/&=/g
y/123456789/012345678/
s/\(.* \)0\(.*\)/\2:\1/
s/^0*\(\(=*\):.*0#*\)\2/\1#/
t
s/=0\(#*\)/9\1=/
t
s/\(=*\) / %\1/
y/#/=/
/.0=/b
s/.* //
s/%=*/&9876543210/g
s/%.\{9\}\(.\)\w*/\1/g
Note that non-ascii characters in the above source code will be escaped (such as \x9f).