Re: Sorting Vietnamese text

[Anonymous Monk]

Note: take what I say here with a grain of salt since I know no Vietnamese.

Here's the Vietnamese alphabet sort order. And here's how to read that chart:

• First column (darkest colour) has the letter in question
• The other columns have the glyphs that sort under that letter
• Therefore, ấ and Ầ and ậ sort under â (will be found in the dictionary under the heading 'â')
• In the case where the two words are otherwise 100% equivalent (except for the diacritics), sort in the left-to-right order given in the chart.

---

Here's how I handled Japanese sorting (hiragana only) based on a similar chart for Japanese:

sub transliterate {
	my $str = shift;
	$str =~
		tr(がぎぐげござじずぜぞだぢづでどばびぶべぼぱぴぷぺぽっゃゅょ)
		  (かきくけこさしすせそたちつてとはひふへほはひふへほつやゆよ);
	return $str;
}

sub gozyuuon {
	$a->{'sort'} cmp $b->{'sort'} ||
	$a->{'reading'} cmp $b->{'reading'};
}

my @rows = (
	{ word => '同時', reading => 'どうじ' },
	{ word => '当日', reading => 'とうじつ' },
	{ word => '同士', reading => 'どうし' },
	{ word => '投資', reading => 'とうし' },
	{ word => '当時', reading => 'とうじ' },
	{ word => '同室', reading => 'どうしつ' },
);

# create a version with the dakuten (") stripped
for (@rows) {
	$_->{'sort'} = transliterate($_->{reading});
}
for my $row (sort gozyuuon @rows) {

	printf "%s・%s\n", $row->{reading}, $row->{word};
}

Japanese is a bit easier since the unicode codepoints are in correct order already; I only needed to handle the equivalent-sort-order characters.

[Anonymous Monk]

And here's what I came up

sub make_sort_order {
	my $str = shift;
	$str =~
	tr(aáàảãạăaáàảãạăắằẳẵặâấầẩẫậbcdđeéèẻẽẹêếềểễệfghiíìỉĩịjklmnoóòỏõọôốồổỗộơớờởỡợpqrstuúùủũụưứừửữựvwxyýỳỷỹỵz)
	  (00000011111111111112222223456777777888888abcddddddefghijjjjjjkkkkkkllllllmnopqrrrrrrsssssstuvwwwwwwx)d;

	return $str;
}

my @words = ('ầm', 'ãm', 'ấm chè', 'ám số');


print $_->[1], "[n" for
	sort { $a->[0] cmp $b->[0] || $a->[1] cmp $b->[1] }
	map  { [ make_sort_order($_), $_ ] } @words;

It's still missing a correct 'secondary sort' (for the edge case when the diacritic-stripped words are identical); it should not be difficult to add once someone figures out a suitable transliteration that sorts asciibetically.

[pdenisowski]

It's still missing a correct 'secondary sort' (for the edge case when the diacritic-stripped words are identical);

(laughs) That's hardly an "edge case" in Vietnamese - there are thousands of minimal pairs where the only difference between the words is the diacritical marks. While it's possible to read and understand Vietnamese typed in (7-bit) ASCII without too much ambiguity (i.e. you can figure out what word is meant from the context), this obviously wouldn't work for a dictionary.

The other issue is that the words in the dictionary need to be sorted in the "correct" order for me to detect duplicates, etc.

I'll try out your suggestion later today - thanks again!

[Anonymous Monk]

I'm probably completely off base here -- why does ám số come before ãm when á sorts at the same point as ã? And the same question with ỳ ạch and ỷ and the other lines...

I think there's something wrong with my alphabet -- some characters being eaten perhaps -- since the tr/// has duplicates? If they're wrong, please re-input the correct alphabetical order into the tr/// lines yourself.

I'm still not sure how spaces play part in all this; I'd sort all the single-character y variants together, and before the two-syllable ones, but the order you've given does not match that and somehow my code handles it handled it even though it shouldn't have.

You should split the string into two before sorting, though. One part for the actual word, the other for the translation.

Anyway, here's a try for a correct secondary sort -- of course, I do not have any words to test it on. It sorts how I expect it to do based on what I said in 1068139, but it does not sort how you expect it to.

Also, why the hell is my tr///d not deleting characters?

Read more... (2 kB)

[Anonymous Monk]

Okay -- the alphabet is only 93 characters per the link in 1068127; you had seven characters extra.

You should clarify what the relation between monosyllables and polysyllables is, and what is the desired collation behaviour between them.

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