両端揃え

昔の英文ワープロ（monospace font で，単語間に空白を挿入して右端を揃える）

昔，FORTRAN で実機を使わずにプログラムしたことがあったなぁ～

func = function(s, w) {
  func2 = function(s) {
    n = length(s)
    len = sum(sapply(s, nchar))
    spaces = w - len
    left.part.spaces = spaces%/%(n - 1)
    left.part.words = n - 1 - spaces%%(n - 1)
    if (left.part.words == n - 1) {
      left.part.words = left.part.words + 1
    }
    sp = paste(rep(" ", left.part.spaces+1), collapse = "")
    s2 = paste(s[1:left.part.words], collapse = substr(sp, 2, nchar(sp)))
    if (n > left.part.words) {
      s3 = paste(s[(left.part.words + 1):n], collapse = sp)
      s2 = paste(s2, s3, sep = substr(sp, 2, nchar(sp)))
    }
    s2
  }
  s = unlist(strsplit(s, " "))
  repeat {
    len = 0
    n.words = length(s)
    for (i in 1:n.words) {
      len = len + nchar(s[i]) + 1
      if (len == w + 1) {
        cat(sprintf("%s\n", paste(s[1:i], collapse = " ")))
        s = s[-(1:i)]
        break
      } else if (len > w + 1) {
        cat(sprintf("%s\n", func2(s[1:(i - 1)])))
        s = s[-(1:(i - 1))]
        break
      }
    }
    if (i == n.words) {
      cat(sprintf("%s\n", paste(s, collapse = " ")))
      break
    }
  }
}
###### テスト
s = "One child, one teacher, one book and one pen can change the world. Education is the only solution. Education first."
for (w in 20:30) {
  func(s, w)
}