--- /dev/null
+#! /usr/bin/perl -w
+
+use strict;
+use warnings;
+use utf8;
+use encoding 'utf-8';
+
+use Unicode::Normalize qw(NFC NFKC);
+
+my $top = shift @ARGV || exit;
+if (! -d $top) { exit; }
+
+checkdir($top);
+
+sub combinable {
+ my $str = shift @_;
+
+ if ($str ne NFC($str)) {
+ return 1;
+ }
+ if ($str ne NFKC($str)) {
+ return 1;
+ }
+
+ return '';
+}
+
+sub checkdir {
+ my $target = shift @_;
+
+ print STDERR "checking '$target'\n";
+ opendir(my $dir, $target) || return $target;
+ my @entries = sort readdir($dir);
+ closedir($dir);
+
+ my @dirs;
+ while (my $entry = shift @entries) {
+ next if ($entry =~ /^\.+$/);
+ if (combinable($entry)) {
+ print "'$target/$entry' can be composed\n";
+ next;
+ }
+ if (-d "$target/$entry") {
+ push @dirs, $entry;
+ next;
+ }
+ }
+
+ while (my $entry = pop @dirs) {
+ checkdir("$target/$entry");
+ }
+}