#!/usr/bin/perl
use strict;
use feature qw{ say };
use warnings;
use Env;
use utf8;
use Time::HiRes qw(gettimeofday tv_interval usleep);
use open ':std', ':encoding(UTF-8)';
use MCE::Loop;
use MCE::Mutex;

my $benchmark = 1; # print timings for loops

my $wordfile="data.dat";
truncate $wordfile, 0;
#$|=1;
# substitute whole words
my %whole = qw{
  going go
  getting get
  goes go
  knew know
  trying try
  tried try
  told tell
  coming come
  saying say
  men man
  women woman
  took take
  lying lie
  dying die
};
# substitute on prefix
my %prefix = qw{
  need need
  talk talk
  tak take
  used use
  using use
};
# substitute on substring
my %substring = qw{
  mean mean
  work work
  read read
  allow allow
  gave give
  bought buy
  want want
  hear hear
  came come
  destr destroy
  paid pay
  selve self
  cities city
  fight fight
  creat create
  makin make
  includ include
};
my $re1 = qr{\b(@{[ join '|', reverse sort keys %whole ]})\b}i;
my $re2 = qr{\b(@{[ join '|', reverse sort keys %prefix ]})\w*}i;
my $re3 = qr{\b\w*?(@{[ join '|', reverse sort keys %substring ]})\w*}
+i;

truncate $wordfile, 0;
my $maxforks = 64;
my $chunksize = 50;  # keep this small, workers append to string buffe
+r
my $t0 = [gettimeofday];
my $mutex = MCE::Mutex->new;

sub process_files {
    my ($mce, $chunk_ref, $chunk_id) = @_;
    my $output = "";

    while (my $infile = shift @{ $chunk_ref }) {
        open my $IN, '<', $infile
            or warn("open error: infile"), MCE->last;
        while (<$IN>) {
            tr/-!"#%&()*',.\/:;?@\[\\\]”_“{’}><^)(|/ /; # no punct "
            s/^/ /;
            s/\n/ \n/;
            s/[[:digit:]]{1,12}//g;
            s/w(as|ere)/be/gi;
            s{$re2}{ $prefix{lc $1} }g;  # prefix
            s{$re3}{ $substring{lc $1} }g;  # part
            s{$re1}{ $whole{lc $1} }g;  # whole

            $output .= "$_";
        }
        close $IN;
    }

    # Choose one: relay (orderly) or mutex (unorderly), but not both.

    # MCE::relay {
    #     open my $OUT, '>>', $wordfile or die "Error opening $wordfil
+e";
    #     print {$OUT} $output;
    #     close $OUT;
    # };

    $mutex->enter(sub {
        open my $OUT, '>>', $wordfile or die "Error opening $wordfile"
+;
        print {$OUT} $output;
        close $OUT;
    });

    undef $output;
    return;
}

sub input_iterator {
    my ($filecount, @data);
    my  $init_data = 1;
    return sub {
        if ($init_data) {
            @data = glob("data-* ??/data-*");
            $filecount = scalar @data;
            say "Parsing $filecount files"; # okay, zero files
            say "maxforks: $maxforks";
            say "chunksize: $chunksize";
            $init_data = 0;
        }
        return unless @data;
        return splice @data, 0, $chunksize;
    };
}

MCE::Loop->init(
    chunk_size  => $chunksize,
    max_workers => $maxforks,
  # init_relay  => 1,  # uncomment, if choosing MCE::relay above
    posix_exit  => 1,
    use_threads => 0,  # use emulated fork on Windows
);

MCE::Loop->run(\&process_files, input_iterator());
MCE::Loop->finish;

my $elapsed = tv_interval($t0);
print "regex: $elapsed\n" if $benchmark;
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