How to manually add diacritics to letters?

Question

ASCII

It would be useful to know how to do it, for example, the letter ё or й in the Russian alphabet. Is it possible somehow to put two dots above the letter "e" in another place, for example? Or the letter ø. How can I cross out any other letter with the same slash?

Answer 1

This is a very twofold situation. Although in some cases (for example, this happens in Mac OS), such characters are indeed combined from two, but this can create problems for software that is focused on the use of "ready-made" rather than "combined" characters. This problem can also occur when searching, when the "combined" e is not considered the equivalent of a single one, and so on.
Well, in itself, the compilation of such signs works very simply.
Unicode has the Combining Diacritical Marks and Combining Diacritical Marks Supplement blocks .
If one of these characters follows a letter character, they are "combined". For example, yocan be formed as U+0435 followed by U+0308. Together it will turn out .
With the symbol ø (o with stroke) it's more difficult. This character is not represented by a combination of two characters, although a strikethrough character exists among the CDM, it is a character with the code U+0338, but this is another strikethrough - long solidus overlay. As you can see, it does not give the desired effect: o̸