#! /usr/bin/gawk -f
# Last edited on 2012-02-13 21:47:15 by stolfilocal

BEGIN {
  # Reads output of "diff --side-by-side", 
  # ouputs consistent "{OLD} {SEP} {NEW}" where
  # blank {SEP} is mapped to "=",
  # blank {OLD} or {NEW} are mapped to "_".
  abort = -1;
}

(abort >= 0) { exit abort; }


(NF==2){
  if ($1 == ">")
    { ow = "_"; sep = $1; nw = $2; }
  else if ($2 == "<")
    { ow = $1; sep = $2; nw = "_"; }
  else 
    { ow = $1; sep = "="; nw = $2; }
  printf "%-30s %s %-30s\n", ow, sep, nw;
  next;
} 

(NF==3){ 
  ow = $1; sep = $2; nw = $3;
  printf "%-30s %s %-30s\n", ow, sep, nw;
  next;
}
  
// { 
  data_error(("bad format"));
}

function data_error(msg)
{
  printf "\n" > "/dev/stderr";
  printf "%s:%d: %s\n", FILENAME, FNR, msg > "/dev/stderr";
  abort = 1; exit 1;
}