# code: http://golf.shinh.org/reveal.rb?sort+by+first+occurrence/tails_1642141392&nbb
# target Nibbles version: 0.21
# commenter version: 0.1.2.181

+ #(concat):[[chr]] 
    =~ #(group all by):[[[chr]]] 
        allLines #(;;@):[[chr]] 
        ~ #(nosort):null 
        #\A 
        #(implicit arg = A):[chr]