anarchy golf - the source code

Grouping by twobit

while""do
s=""w=io.read()for i=1,#w/3 do
a=w
while a>""do
a,c=a:gsub(a:sub(-1),"")s=c==i and i..s or s end
end
print(s)end

Note that non-ascii characters in the above source code will be escaped (such as \x9f).