========== other routines from chapter 4 ==========
# unique - strip adjacent duplicate lines
   character buf1(MAXLINE), buf2(MAXLINE)
   integer equal, getlin
   integer t
   t = getlin(buf1, STDIN)
   while (t ~= EOF) {
      call putlin(buf1, STDOUT)
      for (t = getlin(buf2, STDIN); t ~= EOF; t = getlin(buf2, STDIN))
         if (equal(buf1, buf2) == NO)
            break
      if (t == EOF)
         break
      call putlin(buf2, STDOUT)
      for (t = getlin(buf1, STDIN); t ~= EOF; t = getlin(buf1, STDIN))
         if (equal(buf1, buf2) == NO)
            break
      $@$
   stop
   end
define(FOLD,DOLLAR)
# kwic - make keyword in context index
   character buf(MAXLINE)
   integer getlin
   while (getlin(buf, STDIN) ~= EOF)
      call putrot(buf, STDOUT)
   stop
   end
# putrot - create lines with keyword at front
   subroutine putrot(buf, outfil)
   character type
   character buf(ARB), t
   integer i, outfil
   for (i = 1; buf(i) ~= NEWLINE; i = i + 1) {
      t = type(buf(i))
      if (t == LETTER | t == DIGIT) {      # alpha
         call rotate(buf, i, outfil)      # token starts at "i"
         t = type(buf(i+1))
         for ( ; t == LETTER | t == DIGIT; t = type(buf(i+1)))
            i = i + 1
         $@$
      $@$
   return
   end
# rotate - output rotated line
   subroutine rotate(buf, n, outfil)
   character buf(ARB)
   integer i, n, outfil
   for (i = n; buf(i) ~= NEWLINE; i = i + 1)
      call putch(buf(i), outfil)
   call putch(FOLD, outfil)
   for (i = 1; i < n; i = i + 1)
      call putch(buf(i), outfil)
   call putch(NEWLINE, outfil)
   return
   end
# type - determine type of character
   character function type(c)
   character c
   integer index
#   string digits "0123456789"
   integer digits(11)
#   string lowalf "abcdefghijklmnopqrstuvwxyz"
   integer lowalf(27)
#   string upalf "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
   integer upalf(27)
   data digits(1) /DIG0/
   data digits(2) /DIG1/
   data digits(3) /DIG2/
   data digits(4) /DIG3/
   data digits(5) /DIG4/
   data digits(6) /DIG5/
   data digits(7) /DIG6/
   data digits(8) /DIG7/
   data digits(9) /DIG8/
   data digits(10) /DIG9/
   data digits(11) /EOS/
   data lowalf(01)/LETA/
   data lowalf(02)/LETB/
   data lowalf(03)/LETC/
   data lowalf(04)/LETD/
   data lowalf(05)/LETE/
   data lowalf(06)/LETF/
   data lowalf(07)/LETG/
   data lowalf(08)/LETH/
   data lowalf(09)/LETI/
   data lowalf(10)/LETJ/
   data lowalf(11)/LETK/
   data lowalf(12)/LETL/
   data lowalf(13)/LETM/
   data lowalf(14)/LETN/
   data lowalf(15)/LETO/
   data lowalf(16)/LETP/
   data lowalf(17)/LETQ/
   data lowalf(18)/LETR/
   data lowalf(19)/LETS/
   data lowalf(20)/LETT/
   data lowalf(21)/LETU/
   data lowalf(22)/LETV/
   data lowalf(23)/LETW/
   data lowalf(24)/LETX/
   data lowalf(25)/LETY/
   data lowalf(26)/LETZ/
   data lowalf(27)/EOS/
   data upalf(01) /BIGA/
   data upalf(02) /BIGB/
   data upalf(03) /BIGC/
   data upalf(04) /BIGD/
   data upalf(05) /BIGE/
   data upalf(06) /BIGF/
   data upalf(07) /BIGG/
   data upalf(08) /BIGH/
   data upalf(09) /BIGI/
   data upalf(10) /BIGJ/
   data upalf(11) /BIGK/
   data upalf(12) /BIGL/
   data upalf(13) /BIGM/
   data upalf(14) /BIGN/
   data upalf(15) /BIGO/
   data upalf(16) /BIGP/
   data upalf(17) /BIGQ/
   data upalf(18) /BIGR/
   data upalf(19) /BIGS/
   data upalf(20) /BIGT/
   data upalf(21) /BIGU/
   data upalf(22) /BIGV/
   data upalf(23) /BIGW/
   data upalf(24) /BIGX/
   data upalf(25) /BIGY/
   data upalf(26) /BIGZ/
   data upalf(27) /EOS/
   if (index(lowalf, c) > 0)
      type = LETTER
   else if (index(upalf, c) > 0)
      type = LETTER
   else if (index(digits, c) > 0)
      type = DIGIT
   else
      type = c
   return
   end
define(FOLD,DOLLAR)
define(MIDDLE,40)
define(MAXOUT,80)
# unrot - unrotate lines rotated by kwic
   character inbuf(MAXLINE), outbuf(MAXOUT)
   integer getlin, index
   integer i, j
   while (getlin(inbuf, STDIN) ~= EOF) {
      for (i = 1; i < MAXOUT; i = i + 1)   # blank line
         outbuf(i) = BLANK
      j = MIDDLE
      for (i = 1; inbuf(i) ~= FOLD & inbuf(i) ~= NEWLINE; i = i + 1) {
         j = j + 1         # copy up to FOLD
         if (j >= MAXOUT - 1)
            j = 1
         outbuf(j) = inbuf(i)
         $@$
      if (inbuf(i) == FOLD) {      # copy second half,
         j = MIDDLE         # working backwards
         for (i = index(inbuf, NEWLINE) - 1; i > 0; i = i - 1) {
            if (inbuf(i) == FOLD)
               break
            j = j - 1
            if (j <= 0)
               j = MAXOUT - 2
            outbuf(j) = inbuf(i)
            $@$
         $@$
      for (i = MAXOUT - 2; i > 0; i = i - 1)
         if (outbuf(i) ~= BLANK)   # delete trailing blanks
            break
      outbuf(i+1) = NEWLINE      # terminate line properly
      outbuf(i+2) = EOS
      call putlin(outbuf, STDOUT)
      $@$
   stop
   end