DTDs (SGML)

Birthplace:

ISO

Age:

SGML: 15 years; XML: almost 4 years

Parents:

SGML

Type:

Grammar

Formalism:

ad hoc

Syntax:

XML declaration

  • Remarkably powerful; it's easy to forget how much we left behind

  • Supports entity declarations

  • Compact syntax

  • No local element declarations

  • Relatively impoverished namespace support

  • Few simple types

  • SGML-only features:

    • The "&" connector allows unordered content models

    • Inclusions and exclusions are handy

    • Shortref can mimic tokenized lists with markup