Unicode Demystified

Case Mapping and Case Folding

English speakers are familiar with the concept of case. Every letter in the Latin alphabet comes in two “cases”: upper and lower (or capital and small). Like the Latin alphabet, the Greek, Cyrillic, and Armenian alphabets are cased, or “bicameral.” (The letters in the Georgian alphabet also come in two distinct styles, which for a short time in history were treated as uppercase and lowercase, but generally aren't anymore.)

Occasionally, you will run into situations where you want to convert one letter (or a whole string) from one case to the other. Many word processors, for example, let you convert to uppercase or lowercase with a single command or a character style. On many systems, you can convert everything to ...