Re: [SPOILER] Perl 'Easy' Quiz of the Week #2005-1 (Correction)

On Mon, 24 Jan 2005, Daniel Martin wrote:

> Huh.  No one so far seems to have hit upon the solution I hit upon, which 
> was:  (I've deliberately left out most error checking since I want the main 
> script body uncluttered)

And wouldn't you know it, I left out a piece.  Here's a corrected script:

#!/usr/bin/perl
use strict;

open(STDIN, '<', shift) if @ARGV;
open(STDOUT, '>', shift) if @ARGV;

my $mline='';
my $prefix='';

while(<>) {
  /^(\w+)\.[A-Z]$/ or die "Bad line: $_";
  if ($prefix ne $1) {
    $prefix = $1;
    print $mline;
    $mline = "$prefix.M\n";
  }
  if ($mline lt $_) {
    print $mline;
    $mline = '';
  } elsif ($mline eq $_) {
    $mline='';
  }
  print;
}
print $mline;
__END__