Re: Latin ligatures and Unicode

From: Michael Everson (
Date: Mon Dec 20 1999 - 07:16:41 EST

Ar 13:32 -0800 1999-12-19, scríobh John Jenkins:

>In any event, your case wouldn't be appropriate for
>[use of a ZERO-WIDTH LIGATOR] -- you're
>dealing with a number of ligatures which are compulsory within a specific
>typeface. Forcing the user to specify the formation of these ligatures
>whenever the characters are used -- and risking their showing up in other
>typefaces where they may not be appropriate -- isn't the best way to go.

I have described a mechanism which handles this fine. C + ZWL + K will
display as CK-LIGATURE if the triplet is mapped to a cell in the glyph
table; otherwise only CK will display. No problem.

>For situations where graphic alterations of the characters are required for
>proper display, the Unicode approach is to have the rendering software
>handle it.

You misunderstand the ZWL. What you've described is an inputting operation.
If German is well-behaved enough to trust morphological analysis for
ligature behaviour, then the ZWL can be inserted automatically by software.
This would work as well for fi, ffi, ffl &c ligatures. Unpredictable, rare
and nonce ligatures can be handled by the user inserting the ZWL manually
(as we do the SOFT HYPHEN).

>In this case, it's possible to specify via either OpenType or Apple Advanced
>Typography (AAT) tables in a TrueType font that such ligatures are required
>when using your font. Applications which take advantage of these
>technologies will do the right thing. (For the record, you can also specify
>required ligatures in Metafonts for use with TeX.)

No, it isn't. Because it is impossible to easily apply ligation in the many
different manifestations which are evidenced. In my paper on ZWL I have
described the use of Gaelic ligatures in printed books; it is NOT possible
to decide on two or three global settings which will give the correct
behaviour when turned on or off. The REALITIES are that what we need to
represent, in Latin (Roman, Gaelic, and Fraktur), Greek, Old Church
Cyrillic, Armenian, Runic, Etruscan, and so on are far more complex than
the fun one can have with Hoefler Text.

>4. As I say, there's a proposal for adding a ligation control character,
>but not everybody likes the idea. Which ligatures are appropriate for use
>is too typeface-specific in Latin to have a general solution in plain text

I think you are mistaken, and it is not just Latin that we are talking about.

Michael Everson ** Everson Gunn Teoranta **
15 Port Chaeimhghein Íochtarach; Baile Átha Cliath 2; Éire/Ireland
Vox +353 1 478 2597 ** Fax +353 1 478 2597 ** Mob +353 86 807 9169
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