Unicode Explained

Character and String Data

Processing of character data in computers operates on characters represented by code

numbers. This is often expressed by saying that characters are treated as small integers,

though especially when using Unicode, they need not be that small. A string is usually

represented as a sequence of characters in consecutive storage locations. Otherwise,

the representation and handling of characters varies greatly by programming language

and by software modules.

Constructs and Principles of Processing Characters

For the processing of character data, programming language design needs to solve sev-

eral problems, and the solutions greatly affect the suitability of the language to string-

oriented tasks. You are probably not designing a new programming language, but you

may need to select between some existing languages for a project, or to learn or teach

a language. In the latter area, the phenomenon that psychologists call negative trans-

fer is often problematic: when you have learned one way of doing things in a language

(say, the difference between single and double quotes around a literal), you will im-

plicitly assume that another language uses the same way. Even after you have learned

the difference, you keep forgetting it. Therefore, it is useful to make some explicit com-

parisons.

The key features in the processing of character data in a programming language are:

• Repertoire: ...