## 29.4 Document Type Definitions (cont.)

- To specify finite choices:

  > `<!ATTLIST price currency (USD | EUR | JPY) #REQUIRED>`

- Choices may contain letters, numbers, `-`, `_` or `.`
- `currency` attribute must be specified
- Attribute Defaults:

Default Declaration | Explanation
--- | ---
`#REQUIRED` | Attribute is required
`#IMPLIED` | Attribute is optional
N | Default attribute, used if attribute not specified
`#FIXED` N | Attribute must either be unspecified or contain this value

prev |top |next