The third part contains data and markup, and must conform to the rules described in the second part. The first part is confusing. Declarations are instructions to the SGML parser, and processing instructions are instructions to the application. Marked sections identify and control the disposition of parts of text entities. The syntactic view is created by the parser from the stream of data and delimiters determined by the lexical view.
Elements have attributes , content , and other auxiliary properties.
Attributes are named, and may contain character data or data entity references. The most important property of an element is its generic identifier . The GI determines what attributes, an element has and what its content must look like. The element structure is created by the parser from the stream of markup and data determined by the syntactic view. The Overview An SGML document is a complex thing, which must be processed in several phases.