#! /usr/bin/perl

# Program for testing regular expressions with perl to check that PCRE handles
# them the same.


# Function for turning a string into a string of printing chars

sub pchars {
my($t) = "";

foreach $c (split(//, @_[0]))
  {
  if (ord $c >= 32 && ord $c < 127) { $t .= $c; }
    else { $t .= sprintf("\\x%02x", ord $c); }
  }
$t;
}



# Read lines from named file or stdin and write to named file or stdout; lines
# consist of a regular expression, in delimiters and optionally followed by
# options, followed by a set of test data, terminated by an empty line.

# Sort out the input and output files

if (@ARGV > 0)
  {
  open(INFILE, "<$ARGV[0]") || die "Failed to open $ARGV[0]\n";
  $infile = "INFILE";
  }
else { $infile = "STDIN"; }

if (@ARGV > 1)
  {
  open(OUTFILE, ">$ARGV[1]") || die "Failed to open $ARGV[1]\n";
  $outfile = "OUTFILE";
  }
else { $outfile = "STDOUT"; }

printf($outfile "Perl Regular Expressions\n\n");

# Main loop

NEXT_RE:
for (;;)
  {
  printf "  re> " if $infile eq "STDIN";
  last if ! ($_ = <$infile>);
  printf $outfile "$_" if $infile ne "STDIN";
  next if ($_ eq "");

  $pattern = $_;

  $delimiter = substr($_, 0, 1);
  while ($pattern !~ /^\s*(.).*\1/s)
    {
    printf "    > " if $infile eq "STDIN";
    last if ! ($_ = <$infile>);
    printf $outfile "$_" if $infile ne "STDIN";
    $pattern .= $_;
    }

   chomp($pattern);
   $pattern =~ s/\s+$//;

  # Check that the pattern is valid

  eval "\$_ =~ ${pattern}";
  if ($@)
    {
    printf $outfile "Error: $@\n";
    next NEXT_RE;
    }

  # Read data lines and test them

  for (;;)
    {
    printf "data> " if $infile eq "STDIN";
    last NEXT_RE if ! ($_ = <$infile>);
    chomp;
    printf $outfile "$_\n" if $infile ne "STDIN";

    s/\s+$//;
    s/^\s+//;

    last if ($_ eq "");

    $_ = eval "\"$_\"";   # To get escapes processed

    $ok = 0;
    eval "if (\$_ =~ ${pattern}) {" .
         "\$z = \$&;" .
         "\$a = \$1;" .
         "\$b = \$2;" .
         "\$c = \$3;" .
         "\$d = \$4;" .
         "\$e = \$5;" .
         "\$f = \$6;" .
         "\$g = \$7;" .
         "\$h = \$8;" .
         "\$i = \$9;" .
         "\$j = \$10;" .
         "\$k = \$11;" .
         "\$l = \$12;" .
         "\$m = \$13;" .
         "\$n = \$14;" .
         "\$o = \$15;" .
         "\$p = \$16;" .
         "\$ok = 1; }";

    if ($@)
      {
      printf $outfile "Error: $@\n";
      next NEXT_RE;
      }
    elsif (!$ok)
      {
      printf $outfile "No match\n";
      }
    else
      {
      @subs = ($z,$a,$b,$c,$d,$e,$f,$g,$h,$i,$j,$k,$l,$m,$n,$o,$p);
      $last_printed = 0;
      for ($i = 0; $i <= 17; $i++)
        {
        if ($i == 0 || defined $subs[$i])
          {
          while ($last_printed++ < $i-1)
            { printf $outfile ("%2d: <unset>\n", $last_printed); }
          printf $outfile ("%2d: %s\n", $i, &pchars($subs[$i]));
          $last_printed = $i;
          }
        }
      }
    }
  }

printf $outfile "\n";

# End