##
use strict;
use warnings;
my $data = "line1\nfoobar\nline3\n";
$data =~ s{(foo)(bar)}{
my $one = $1;
my $two = $2;
$one .= <<'END_TEXT';
Insert 1
Insert 2
END_TEXT
$one.$two;
}e;
print $data;
####
$data =~ s{(foo)(bar)}{
my $one = $1;
my $two = $2;
$one .= <<'END_TEXT';
$one.$two;
}e;
Insert 1
Insert 2
END_TEXT