RE: Why no combining‐character form for U+00F8?

From: Erkki I Kolehmainen <>
Date: Thu, 16 Aug 2012 19:32:15 +0300

Although the stroke is not a diacritic, keyboard drivers can be made to generate atomic characters with stroke by using a dead letter key for stroke together with the base character. The Finnish keyboard layout standard SFS 5966 works in this manner for O (for e.g., Danish), L (Polish), H (Maltese), D (Northern Sámi), T (Northern Sámi), and G (Skolt Sámi).

Erkki I. Kolehmainen

-----Alkuperäinen viesti-----
Lähettäjä: [] Puolesta Jukka K. Korpela
Lähetetty: 16. elokuuta 2012 18:56
Aihe: Re: Why no combining‐character form for U+00F8?

2012-08-16 18:31, Ian Clifton wrote:

> Having just been to Norway, and wanting to email my friends all about
> it, I came across a curiosity: neither of the combining characters
> U+0337, U+0338 seem to work in usually‐reliable Emacs, and indeed
> U+00F8 LATIN SMALL LETTER O WITH STROKE doesn’t seem to have a
> decomposed form, according to UnicodeData.txt. I’m sure this can’t be
> an oversight?

It isn’t an oversight but an intentional decision.

The letter “ø” (historically originating from a ligature of “o” and “e”) could have been analyzed as consisting of the letter “o” and a diacritic mark. Instead, it was coded as an “atomic” character that is not decomposable in any way.

This may sound illogical, as another Scandinavian letter, “ö” (also originating from a ligature of “o” and “e”, the latter in small size above the “o”) is encoded as canonically decomposable.

Similarly, the letters “ł” and “đ” were encoded as “atomic.” In a sense, it’s just the way it is, but I think I can see the reasoning behind this. Although strokes across letters are comparable to diacritic marks in a sense, and surely historically, the also differ from them in essential ways. They cross over letters instead of just sitting above, below, or otherwise near a base letters. perhaps more importantly, they differ in placement, width, and angle: compare e.g. “ø”, “ł”, and “đ”
with each other. If the stroke were defined as a diacritic, its identity would be rather vague.

Received on Thu Aug 16 2012 - 11:35:00 CDT

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