Document Structure

The general structure of an SGML document is:

1. SGML declaration.
2. Document type declaration.
3. Document contents.

The Snafu DTD requires an SGML declaration with three changes from the default:

• NAMELEN must be increased, with 34 the new default. This determines the maximum length of element and entity names.
• FORMAL YES is specified to allow the use of formal public identifiers within the prolog.
• TOTALCAP must be increased, by default to 100000.

The basic document type declaration can be one of:

<!DOCTYPE spaper PUBLIC "-//Houston//DTD snafu5//EN">
<!DOCTYPE smemo PUBLIC "-//Houston//DTD snafu5//EN">
<!DOCTYPE sletter PUBLIC "-//Houston//DTD snafu5//EN">

This will give version 5 of each document type. Earlier versions lack some of the features described in this document.

A "document type declaration subset" may need to be added to the `DOCTYPE' declaration, for example when declaring an external entity such as a figure:

<!DOCTYPE spaper PUBLIC "-//Houston//DTD snafu5//EN"[
  <!ENTITY dogfig SYSTEM "dog.ps" NDATA EPSF>
]>