7. Notation declarations

The purpose of a notation declaration is to define the format of some external non-XML file, such as a sound or image file, so you can refer to such files in your document.

The general form of a notation declaration can be either of these:

    <!NOTATION nname PUBLIC std>
    <!NOTATION nname SYSTEM url>

where nname is the name you are giving to the notation; std is the published name of a public notation, and url is a reference to a program that can render a file in the given notation.

There are four steps to connecting an attribute to a notation:

Declare the notation. Example:
```
    <!NOTATION jpeg PUBLIC "JPG 1.0">
```

Declare the entity. For example:

    <!ENTITY bogie-pic SYSTEM
        "http://stars.com/bogart.jpg" NDATA jpeg>

Declare the attribute as type ENTITY. For example:

    <!ATTLIST star-bio pin-shot ENTITY #REQUIRED>

Use the attribute:

    <star-bio pin-shot="bogie-pic">...</star-bio>

Constructing a Document Type Definition (DTD) for XML

7. Notation declarations