#!/usr/bin/perl -w
  # Copyright 2012  Johns Hopkins University (Author: Daniel Povey)
  # Apache 2.0.
  
  # This program is a bit like ./sym2int.pl in that it applies a map
  # to things in a file, but it's a bit more general in that it doesn't
  # assume the things being mapped to are single tokens, they could
  # be sequences of tokens.  
  
  # This program takes two arguments, which may be files or "-" for the
  # standard input.  Both files must have lines with one or more fields,
  # interpreted as a map from the first field (a string) to a list of strings.
  # if the first file has as one of its lines
  # A x y
  # and the second has the lines
  # x P
  # y Q R
  # then the output of this program will be
  # A P Q R
  # 
  # Note that if x or y did not appear as the first field of file b, we would
  # print a warning and omit the whole line rather than map it to the empty
  # string.
  
  if(@ARGV != 1) {
    print STDERR "Usage: apply_map.pl map <input >output
  " .
      "e.g.: echo A B | apply_map.pl <a.txt
  " .
      "where a.txt is:
  " .
      "A a1 a2
  " .
      "B b
  " .
      "will produce:
  " .
      "a1 a2 b
  ";
  }
  
  ($map) = @ARGV;
  open(M, "<$map") || die "Error opening map file $map: $!";
  
  while (<M>) {
    @A = split(" ", $_);
    @A >= 1 || die "apply_map.pl: empty line.";
    $i = shift @A;
    $o = join(" ", @A);
    $map{$i} = $o;
  }
  
  while(<STDIN>) {
    @A = split(" ", $_);
    for ($x = 0; $x < @A; $x++) {
      $a = $A[$x];
      if (!defined $map{$a}) { die "compose_maps.pl: undefined key $a
  "; }
      $A[$x] = $map{$a};
    }
    print join(" ", @A) . "
  ";
  }