use strict;
use warnings;
use feature 'say';

use MCE::Map;

MCE::Map-> init(
    chunk_size => 1, 
    max_workers => 4,
    user_begin => sub {
        print "## ", MCE-> wid, " started\n";
    },
    user_end => sub {
        print "## ", MCE-> wid, " completed\n";
    },
);

my @a = MCE::Map-> run( sub { $_ }, [ 0 .. 9 ]);
print "\n", "@a", "\n";

say $MCE::VERSION;
[download]

This, of course, prints:

## 1 started
## 3 started
## 2 started
## 4 started
## 1 completed
## 3 completed
## 2 completed
## 4 completed

0 1 2 3 4 5 6 7 8 9
1.882
[download]

I want to make dependency on MCE, in my module, very optional i.e. triggered by rare circumstances only. Replacing "use" with "require" results in just first 4 lines of output and process running indefinitely, 4 cores fully loaded.

MCE::Map being just a convenience, I can do this instead:

use strict;
use warnings;
use feature 'say';

require MCE;

my @in = ( 0 .. 9 );
my @out;

my $mce = MCE-> new(
    chunk_size => 1, 
    max_workers => 4,
    user_begin => sub {
        print "## ", MCE-> wid, " started\n";
    },
    user_end => sub {
        print "## ", MCE-> wid, " completed\n";
    },
    user_func => sub { MCE-> gather( $_ )},
    input_data => \@in,
    gather => \@out,
);

$mce-> run;
say "@out";
$mce-> shutdown;
[download]

And it runs perfectly. I understand I'll have to deal now with ordering of the output, it's not an issue. But that's the reason I was hoping to use MCE::Map to make it easier. Is this a bug?

In general, is very optional (documented) dependency on something big and complex as MCE a bad-bad-bad idea? I guess I'll have to indicate minimum required MCE version then, which for example above would be... 1.500?

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