#!/bin/sh
delay=0 anchordist=0
while [ $# -gt 0 ]; do
  case $1 in
    -delay) delay=1 ;;
    -docanchor) anchordist="$2"; shift ;;
    *) echo "This can't happen -- $1 passed to noidx" 1>&2 ; exit 1 ;;
  esac
  shift
done
nawk 'function insertafter(i, s, n) {
        for(n = nextline++; n - 1 > i; n--) lines[n] = lines[n-1]
        lines[n] = s
      }
      function slipin(s) {
        lines[nextline++] = s
      }
      function fill_charcode_table(i) {
        if (charcode_table[64])
          return
        for (i = 0; i < 256; i++) {
          charcode_table[sprintf("%c", i)] = i
        }
      }

      function charcode(s, i) {
        fill_charcode_table()
        return charcode_table[substr(s, i, 1)]
      }       
      function fill_crc_table(POLY, sum, i, j) {
        POLY = 245 * 4096 * 4096
        if (crc_table[0]) {
          return
        }
        for (i = 0; i < 256; i ++) {
          sum = 0
          for (j = 7; j >= 0; j -= 1) {
            if (and(i, lshift(1, j)) != 0) {
              sum = xor(sum, rshift(POLY, j))
            }
          }
          crc_table[i] = sum
        }
      }

      function crc(s, sum, i) {
        fill_crc_table()
        sum = 0
        for (i = 1; i <= length(s); i++) {
          sum = xor(rshift(sum, 8), crc_table[and(xor(sum, charcode(s, i)), 255)])
        }
        return sum
      }
      function newdefnlabel(arg, label) {
        defcount[arg] = defcount[arg] + 1
        label = "NW" curfile "-" uniqueid(arg) "-" alphacode(defcount[arg])
        return label
      }
      function newdocslabel() {
        newdocslabelcount++
        return "NWD" alphacode(newdocslabelcount)
      }
      function addlabel(tbl, arg, label, marker) {
        marker = " " label
        if (!tailmatch(tbl[arg], marker)) 
          tbl[arg] = tbl[arg] marker
        return label
      }
      function tailmatch(string, tail, pos) {
        pos = length(string) - length(tail) + 1
        if (pos > 0 && substr(string, pos) == tail)
          return 1
        else
          return 0
      }
      function addud(udlist, name, arg, label, s) {
        s = " " name "{" label "}"
        if (!tailmatch(udlist[arg], s))
          udlist[arg] = udlist[arg] s
      }
      function listget(l, i, n, a) {
        n = split(l, a)
        return a[i]
      }
      function uniqueid(name, key) {
        if (uidtable[name] == "") {
          key = make_key(name)
          # gsub(/[\]\[ \\{}`#%&~_^<>"-]/, "*", key)  # old
          gsub(/[^a-zA-Z0-9!$()*+,.\/:;=?@|]/, "*", key)
          keycounts[key] = keycounts[key] + 1
          uidtable[name] = key 
          if (keycounts[key] > 1)
            uidtable[name] = uidtable[name] "." alphacode(keycounts[key])
        }
        return uidtable[name]
      }
      function old_make_key(name,   key, l) {
         l = length(name)
         sub(/^.*\//, "", name)
         key = substr(name, 1, 3)
         if (l >= 3) key = key alphacode(l)
         return key
      }
      function make_key(name) {
        return alphacode(crc(name))
      }
      function lognowebchunks(l, j, n, x) {
        if (loggednowebchunks > 0) return
        loggednowebchunks = 1
        delete allchunks[0]
        n = alphasort(allchunks)
        print "@xref beginchunks"
        for (j = 0; j < n; j++) {
          name = sorted[j]; delete sorted[j]
          printf "@xref chunkbegin %s %s\n", 
              (anchorlabel[name] != "" ? anchorlabel[name] : "nw@notdef"), name
          m = split(chunkud[name], a)
          for (k = 1; k <= m; k++) 
            if (a[k] ~ /^use/) 
              printf "@xref chunkuse %s\n", substr(a[k], 5, length(a[k])-5)
            else if (a[k] ~ /^defn/) 
              printf "@xref chunkdefn %s\n", substr(a[k], 6, length(a[k])-6)
          print "@xref chunkend"
        }
        print "@xref endchunks"
      }
      function lognowebindex(l, j, n, x) {
        if (loggednowebindex > 0) return
        loggednowebindex = 1
        delete allidents[0]
        n = alphasort(allidents)
        print "@index beginindex"
        for (j = 0; j < n; j++) {
          name = sorted[j]; delete sorted[j]
          printf "@index entrybegin %s %s\n", 
              (indexanchorlabel[name] != "" ? indexanchorlabel[name] : "nw@notdef"), name
          m = split(indexud[name], a)
          for (k = 1; k <= m; k++) 
            if (a[k] ~ /^use/) 
              printf "@index entryuse %s\n", substr(a[k], 5, length(a[k])-5)
            else if (a[k] ~ /^defn/) 
              printf "@index entrydefn %s\n", substr(a[k], 6, length(a[k])-6)
          print "@index entryend"
        }
        print "@index endindex"
      }
      function alphasort(a, x, n) {
        n = 0
        for (x in a) 
          n = insertitem(x, n)
        return n
      }
      function insertitem(x, n, i, tmp) {
        sorted[n] = x
        sortkeys[n] = sortkey(x)
        i = n
        while (i > 0 && (sortkeys[i] <  sortkeys[i-1] ||
                         sortkeys[i] == sortkeys[i-1] && sorted[i] < sorted[i-1])) {
          tmp = sortkeys [i]; sortkeys [i] = sortkeys [i-1]; sortkeys [i-1] = tmp
          tmp = sorted[i]; sorted[i] = sorted[i-1]; sorted[i-1] = tmp
          i = i - 1
        }
        return n + 1
      }
      function sortkey(s) {
        return tolower(s) "\n" s   # relies on \n sorting lower than other characters
      }  
      function alphacode(n) {
        if (n < 0) 
          return "-" alphacode(-n)
        else if (n >= alphacodelen) 
          return alphacode(n / alphacodelen) alphacode(n % alphacodelen)
        else
          return substr(alphacodes, n+1, 1)
      }
      BEGIN { curfile = "standard input?"
              lastchunkbegin = "never any chunks?" ;
              allchunks[0] = 0 ; allidents[0] = 0 ; indexlabels[0] = 0 
              defanchors[0] = 0 ; uses[0] = 0 ; anchorlabel[0] = 0 ; indexanchorlabel[0] = 0
              thesedefns[0] = 0; theseuses[0] = 0 ;
              defcount[0] = 0 ;
              udlist[0] = 0 ;
              uidtable[0] = 0
              keycounts[0] = 0 ;
              sorted[0] = 0; sortkeys[0] = 0;
              alphacodes = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
              alphacodelen = length(alphacodes) ; nextline = 0 }
      /^@file /     { curfile = uniqueid(substr($0, 7)) }
      /^@begin /    { lastchunkbegin = $0 }
      /^@end docs / { if (anchordist > 0) { n = anchordist
                                            lastanchorlabel = newdocslabel()
                                            for(i = nextline - 1; i >= 0; i--) {
                                              if (n == 0 || lines[i] ~ /^@begin docs /) {
                                                insertafter(i, "@xref label " lastanchorlabel)
                                                i = -1    # cause loop to terminate
                                              } else if (lines[i] == "@nl") {
                                                n--
                                              }
                                            }
                                          } }
      /^@end code / { lastanchorlabel = "" }
      /^@defn /     { arg = substr($0, 7)
                      allchunks[arg] = 1
                      lastdefnlabel = newdefnlabel(arg)
                      slipin("@xref label " lastdefnlabel)
                      if (lastanchorlabel == "") lastanchorlabel = lastdefnlabel
                      if (anchorlabel[arg] == "") anchorlabel[arg] = lastanchorlabel
                      addlabel(defanchors, arg, lastanchorlabel)
                      addud(chunkud, "defn", arg, lastanchorlabel)
                      thisusecount = 0
                    }
      /^@use /      { if (lastchunkbegin ~ /^@begin code /) {
                        arg = substr($0, 6)
                        allchunks[arg] = 1
                        slipin("@xref label " lastdefnlabel "-u" (++thisusecount))
                        addlabel(uses, arg, lastanchorlabel)
                        addud(chunkud, "use", arg, lastanchorlabel)
                      }
                    }
      /^@index use /  { arg = substr($0, 12)
                        allidents[arg] = 1
                        if (lastanchorlabel != "") addud(indexud, "use", arg, lastanchorlabel)
                      }
      /^@index defn / { arg = substr($0, 13)
                        allidents[arg] = 1
                        if (lastanchorlabel != "") {
                          l = lastanchorlabel
                        } else {
                          l = newdocslabel()
                          slipin("@xref label " l)
                        }
                        addud(indexud, "defn", arg, l)
                        if (indexanchorlabel[arg] == "") indexanchorlabel[arg] = l
                        slipin("@xref ref "  l) # bug fix
                      }
      /^@index localdefn / { arg = substr($0, 18)
                        allidents[arg] = 1
                        if (lastanchorlabel != "") {
                          l = lastanchorlabel
                        } else {
                          l = newdocslabel()
                          slipin("@xref label " l)
                        }
                        addud(indexud, "defn", arg, l)
                        if (indexanchorlabel[arg] == "") indexanchorlabel[arg] = l
                        slipin("@xref ref "  l) # bug fix
                      }
      { lines[nextline] = $0; nextline++ }
      END { 
        for (i = 0; i < nextline; i ++) {
          line = lines[i]
          if (line ~ /^@begin /) {
              if (delay && lastchunkbegin == line) { print "@nl"
                                                     print "@nl"
                                                     lognowebchunks()
                                                     lognowebindex() 
                                                   }
              print line
              for (x in thesedefns) delete thesedefns[x]
              for (x in theseuses) delete theseuses[x]
              thischunk = ""
          } else if (line ~ /^@defn /) {
              thischunk = substr(line, 7)
              printf "@xref ref %s\n", anchorlabel[thischunk]
              print line
              defout[thischunk]++
              if (defout[thischunk] > 1)
                printf "@xref prevdef %s\n", listget(defanchors[thischunk], defout[thischunk]-1)
              if (defout[thischunk] < defcount[thischunk])
                printf "@xref nextdef %s\n", listget(defanchors[thischunk], defout[thischunk]+1)
              if (defout[thischunk] == 1) {if (defcount[thischunk] > 1) {
                                             print "@xref begindefs"
                                             n = split(defanchors[thischunk], a)
                                             for (j = 2; j <= n; j++) printf "@xref defitem %s\n", a[j]
                                             print "@xref enddefs"

                                           }
                                           if (uses[thischunk] != "") {
                                             print "@xref beginuses"
                                             n = split(uses[thischunk], a)
                                             for (j = 1; j <= n; j++) printf "@xref useitem %s\n", a[j]
                                             print "@xref enduses"
                                           } else {
                                             printf "@xref notused %s\n", thischunk
                                           }}
          } else if (line ~ /^@use /) {
              arg = substr(line, 6)
              printf "@xref ref %s\n", (anchorlabel[arg] == "" ? "nw@notdef" : anchorlabel[arg])
              print line
          } else if (line ~ /^@index defn /) {
              arg = substr(line, 13)
              thesedefns[arg] = 1
              # no xref ref because of bug fix
              # if (indexanchorlabel[arg] != "") 
              #   printf "@xref ref %s\n", indexanchorlabel[arg]
              print line
          } else if (line ~ /^@index localdefn /) {
              arg = substr(line, 18)
              thesedefns[arg] = 1
              # no xref ref because of bug fix
              # if (indexanchorlabel[arg] != "") 
              #   printf "@xref ref %s\n", indexanchorlabel[arg]
              print line
          } else if (line ~ /^@index use /) {
              arg = substr(line, 12)
              theseuses[arg] = 1
              if (indexanchorlabel[arg] != "") 
                printf "@xref ref %s\n", indexanchorlabel[arg]
              print line
          } else if (line ~ /^@end code/) {
              for (x in thesedefns)
                delete theseuses[x]
              delete thesedefns[0]
              n = alphasort(thesedefns)
              if (n > 0) {
                print "@index begindefs"
                for (j = 0; j < n; j++) {
                  m = split(indexud[sorted[j]], a)
                  for (k = 1; k <= m; k++) 
                    if (a[k] ~ /^use/) 
                      printf "@index isused %s\n", substr(a[k], 5, length(a[k])-5)
                  printf "@index defitem %s\n", sorted[j]
                  delete sorted[j]
                }
                print "@index enddefs"
              }
              delete theseuses[0]
              n = alphasort(theseuses)
              if (n > 0) {
                print "@index beginuses"
                for (j = 0; j < n; j++) {
                  m = split(indexud[sorted[j]], a)
                  for (k = 1; k <= m; k++) 
                    if (a[k] ~ /^defn/) 
                      printf "@index isdefined %s\n", substr(a[k], 6, length(a[k])-6)
                  printf "@index useitem %s\n", sorted[j]
                  delete sorted[j]
                }
                print "@index enduses"
              }
              print line
          } else if (line ~ /^@text /) {
              # grotesque hack to get indexes in HTML
              if (thischunk == "") { # docs mode
                arg = substr(line, 7)
                if      (arg == "<nowebchunks>") lognowebchunks()
                else if (arg == "<nowebindex>")  lognowebindex()
                else print line
              } else {
                print line
              }
          } else {
              print line
          }
          delete lines[i]
        }
        if (!delay) { print "@nl"
                      print "@nl"
                      lognowebchunks()
                      lognowebindex() 
                    }
      }' delay=$delay anchordist=$anchordist