> (This comment doesn't reflect well on me. Fortunately, this is a pseudonymous account.)

If anyone thinks less of you because you simply know five swearwords, it's pretty much their problem.

It also censors Charles Dickens and peacock. But add some random capitalization, and you can swear all you want.

I remember playing Ragnarok Online back in 2005ish. I was working on my merchant. Merchants had an ability to get better sale prices to NPCs, so one common way to make money by buying some item from players in bulk for more than they could get vendoring it, and you make margin on it by getting even more. Arbitrage!

My skills weren't high enough to compete with other merchants on the highest margin common items, so I decided to try one of the lower priced things. Squeeze into some kind of niche, you see.

Around this time, I discovered the censorship list was enforced client side (oh the wild west old days...),

To make a long story long, there were these crabs and they dropped an item called "nippers". They were kind of a cute thing because though that was what they were called by the game's creators, the game censored you for saying it. I removed "nip" from the list of gylphs, I could shout an offer to buy them without interference. This let me buy these items from players without any competition. As the only dedicated purchaser, I was able to preserve a much higher margin.

Thanks to a soft monopoly preserved by regulations and information asynchrony, I was able to make significantly more money than I would have otherwise. That taught a lot of lessons to ~15 year old me. If only I could have applied those lessons in the real world!

I had occasion to write a chat server for a small gaming service once. The way I came up with to do the profanity filter ended up working a lot better than I expected it to, and avoided the problem you describe.

It worked like this.

1. Make a copy of the text to be filtered, modified as follows.

-- change upper case letters to lower case

-- change 0 to o, 1 to i, 3 to e, 5 to s, and vowels with various accent marks to the corresponding unaccented lower case vowel

-- discard anything else

For example, if the input was "Start the assault. let's f-u-c-k them" it would become "starttheassaultletsfuckthem".

2. Scan this for any substrings that are on the bad word list. In this case it would find "ass" and "fuck" [1].

3. If no bad words are found, the original string is returned and we are done.

4. For each word in the original string, look it up in the dictionary (I believe I used /usr/dict/words). Note the ranges of character positions in the original string of the words that are spelled correctly.

5. For each bad word found in the filtered string, if all of its characters came from positions in the original string that were part of correctly spelled words, leave it alone. Otherwise, asterisk out its characters in the original string.

In the above example, "ass" would be left alone because all of its characters came from "assualt" which is recognized as a correctly spelled word. None of "fuck" came from correctly spelled words, so it would get zapped. The final result would be

  start the assault. let's *-*-*-* them.

[1] Well...actually not. I just checked my archives and found the chat server bad word list. It did not include "ass".

I had occasion to write a chat server for a small gaming service once. The way I came up with to do the profanity filter ended up working a lot better than I expected it to, and avoided the problem you describe.

It worked like this.

1. Make a copy of the text to be filtered, modified as follows.

-- change upper case letters to lower case

-- change 0 to o, 1 to i, 3 to e, 5 to s, and vowels with various accent marks to the corresponding unaccented lower case vowel

-- discard anything else

For example, if the input was

  start the assault. let's f-u-c-k them

it would become

  starttheassaultletsfuckthem 

2. Scan this for any substrings that are on the bad word list. In this case it would find "ass" and "fuck" [1].

3. If no bad words are found, the original string is returned and we are done.

4. For each word in the original string, look it up in the dictionary (I believe I used /usr/dict/words). Note the ranges of character positions in the original string of the words that are spelled correctly.

5. For each bad word found in the filtered string, if all of its characters came from positions in the original string that were part of correctly spelled words, leave it alone. Otherwise, asterisk out its characters in the original string.

In the above example, "ass" would be left alone because all of its characters came from "assualt" which is recognized as a correctly spelled word. None of "fuck" came from correctly spelled words, so it would get zapped. The final result would be

  start the assault. let's *-*-*-* them

[1] Well...actually not. I just checked my archives and found the chat server bad word list. It did not include "ass".

I assume it censors 'Spurs' to '_____'.

Ah, now if you want to bring tribalism into this, here's the obligatory joke:

What are the only 3 English football clubs with swear words in their names?

1. Scunthorpe United, 2. Arsenal, 3. F*ing Man United!

I tried this in their tool, "shitwat" comes out as "s*wat"

Recursively how?

That sounds unlikely, ligatures are two or more consecutive graphemes graphemes joined into a single glyph, but only visually. The underlying text is unmodified, so as far as the renderer is concerned, the text is still "arsenal".

Why would you censor "donkey"?