http://www.rubyist.net/~matz/20050607.html#p02
のとおりにQu風にすると、

a = [1, 2, 3]
last = a.length - 1
a.each_with_index do |n, i|
　if i == 0
　　print "[", n, ","
　elsif i == last
　print n, "]"
　else
　 print n, ","
　end
end

が、

a = [1, 2, 3]
last = a.length - 1
a.each_with_index do |n, i|
　if i == 0
　　print "[", n, ","
　elsif i == last
　print n, "]"
　else
　 print n, ","
　;;
;;


となる。あ、ちょっといいかもとおもた。