How to Create Compound Characters Inside a Font

Question

Wondering if it's possible to organize a font to have features such as combining characters.

Basically, I'm wondering if you can design a font in a modular way so that it can have these features:

• superscripts/subscripts
• diacritical marks
• composable shapes

So for example, say I have a vertical line character like |, and I want a double vertical line character not just by using two |, e.g. ||. I would like this: ‖. So I would have in the font a single line character |, and then ~somehow~ would combine two of them together when writing so that I get the ‖ character. This would mean reusing font assets/symbols/shapes/glyphs.

A more complex example would be like combining ‖ and the accent mark ´: ‖́. So now we have two | and and one ´ combined into a single "character".

This would make it so you don't have to predefine every combination of glyph/symbol, which could be a lot. Say for example, I have a-z, and 10 diacritical marks for the top, and 10 possible for the bottom. That is 10² or 100 combinations of diacritical marks for each character. So instead of 26 + 10 + 10 = 46 glyphs, the font would have 26 * 100 = 2,600 glyphs, a big difference. Add on top of that the ability to support super and subscripts, and that could easily be 2,600 * 3 = 7,800 glyphs, vs. 46. I would also like to support nested superscripts. But maybe sub/superscripts should be saved for a separate question b/c it might be unrelated and/or complicated.

Then there is the question of how the keyboard is mapped to all of these combinations, which I am not familiar with.

So my question is, if it is possible to organize a font to have these features of combining characters into "complex glyphs", from "primitive glyphs". And if so, how to map it to the keyboard, since 2,600 possible combinations is a lot more than the number of keys on the keyboard, you would probably have some sort of "key codes" or "key combinations" to enter to get a character, not sure about that.

Answer 1

Those characters types already exist as is shown in this answer: https://graphicdesign.stackexchange.com/a/109918/120647

As you can see in the gif, selecting a different character at the Glyphs Panel in Illustrator, at the top appear the unicode number. Accessing the operating system's character map you can search the unicode number and keyboard combination.

Designing a new typeface not only refers to its formal design but also to its kerning and specifically the kerning pairs. In that type of characters a special kerning pair must be defined when combining with other glyphs.

The case of the double vertical line is as simple as defining a special vertical line with a negative kerning at the font editor you use to create the font. In the use you can combine this special character with the regular vertical line. The same with three characters: