#!/usr/bin/perl

use strict;
use warnings;

my @order = qw(
    Using
    Options
    Pragmas
    Extensions
    Differences
    Internals
    );

my %h;

my %s;

foreach my $fn (@ARGV) {
    open my $fh, "<$fn" or die "$!: could not open $fn";
    while(<$fh>) {
        /^(\{\-|\/\*)[#@](\w+)(\s+(\d+))?\s*$/ or next;
        my ($section,$text,$order) = ($2,"",defined $4 ? $4 : 100);
        while(<$fh>) {
            /^(\-\}|\*\/)\s*$/ and last;
            $text .= $_;
        }
        $s{$section} ||= [];
        push @{$s{$section} ||= []}, [$order,$text];
        $h{$section}{files} .= ":$fn";
    }
}

foreach (keys %s) {
    $h{$_}{text} = join "\n",map { $_->[1] } sort { $a->[0] <=> $b->[0] } @{$s{$_}};
}

foreach(@order) {
    print "\n# $_\n\n";
    $h{$_}{text} =~ s/^(#+ )/#$1/mg;
    print $h{$_}{text};
}

foreach(keys %h) {
    print STDERR $_," ",$h{$_}{files},"\n";
}