open my $text, '<', 'test.txt';
$/ = $, = '['; # input record separator, output field separator
my %mapping; # existing endnote number --> number in ascendig order
my $endnote_counter = 1;
if (@ARGV && $ARGV[0] eq '--by_endnote_order') {
while (<$text>) { # skip main text
last if (/\@footnote:/);
}
while (<$text>) { # compute mapping in endnotes section
if (/^(\d+)]/) {
$mapping{$1} //= $endnote_counter++;
}
}
}
my @endnotes;
seek($text, 0, 0); # nop if not --by_endnote_order
while (<$text>) { # re-map endnote references in main text
if (/^(\d+)(].*)$/ms) {
$mapping{$1} //= $endnote_counter++; # nop if --by_endnote_order
$_ = $mapping{$1}.$2;
}
print;
last if (/\@footnote:/);
}
while (<$text>) { # re-order endnotes
chomp;
if (/^(\d+)(].*)$/ms) {
$_ = $mapping{$1}.$2;
}
$endnotes[$mapping{$1}] .= ($endnotes[$mapping{$1}] ? '[' : q()) . $_;
}
print grep {$_} @endnotes; # omit endnote references without definition
