v.rb

# encoding: UTF-8
str = <<'EOT'
連続する、句読点。
どう扱えば、、いいのか。。。
EOT

punc = "、。，．"
h = "ー「」→↑←↓＝…"
v = "｜¬∟↓→↑←॥："
hv = (h + v)
vh = (v + h)
lines = []
str.tr(hv, vh).each_line{|line|
  lines << line.chomp.split(/([#{punc}]+)/o)
}
status = []
lines.each{|line| status << line.each_slice(2).with_object(["", ""]){|(main, puncta), (punctuation, mains)|
    punctuation << "　" * main.size.pred + puncta
    mains << main + "　" * puncta.size.pred
  }}
status.flatten!.each{|line| line.chomp!("　")}
max = status.map(&:size).max
status = status.map{|line|
  line.chars.fill("　", line.size...max)
}.transpose.map{|line| line.reverse.join}.join("\n")
status.gsub!(/　+$/, "")
puts status
# >> ど　連
# >> う　続
# >> 扱　す
# >> え　る、
# >> ば、句
# >> 　、読
# >> い　点。
# >> い
# >> の
# >> か。
# >> 　。
# >> 　。