#!/usr/bin/perl --
use strict;
use warnings;
use v5.10.0;
use Data::Dump qw/ dd /;
my $blah = qq{anything \\\nblah\nanything \\\nblah};
dd( $blah );
print "$blah\n\n";

#~ use re 'debug';
my $reblah = qr{

(?<multiline>
    (?: ^ [^\r\n]* \\ [\r\n]* )+  ## multiline MANY times
    (?: ^ [^\r\n]* [\r\n]+ )      ## but always ENDS with oneline
)
|
(?<oneline>  ^ [^\r\n]* [\r\n]+ )
}smx;

while( $blah =~ m{$reblah}g ){
    dd( { %+  } );
}

__END__
"anything \\\nblah\nanything \\\nblah"
anything \
blah
anything \
blah

{ multiline => "anything \\\nblah\n" }
{ oneline => "anything \\\n" }
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