How about using a bitmap state hash, deleting as you go to limit memory footprint. Single pass..... 

my %states = (
    'begin'      => 1,
    'doing-work' => 2,
    'complete'   => 4,
);
my $re = join '|', keys %states;
$re = qr/^(\S+)\s*($re)/;

my %fail_decode = (
    6 => 'no begin',
    5 => 'no doing work',
    4 => 'no begin or doing work',
    3 => 'no complete',
    2 => 'no begin or complete',
    1 => 'no doing work or complete',
);

my %status;
while(<DATA>) {
    next unless /$re/;
    $status{$1} += $states{$2};
    delete $status{$1} if $status{$1} == 7;
}

printf "$_\t%s\n", $fail_decode{$status{$_}} for keys %status;

__DATA__
foo begin
bar begin
baz complete
foo doing-work
foo complete
bar doing-work

[download]

cheers

tachyon

In reply to Re: Efficiently parsing a large file by tachyon
in thread Efficiently parsing a large file by neilwatson

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.