GNML has following main properties:

•It is in text format: The GNML tags appear in a text as text tags, delimited by special characters. Tags may be displayed on the screen (that means they are visible in the text) or hidden.

•It is interpreted: The tags in text are processed and interpreted by the GN4 text justification engine when a text is displayed or printed. The built-in tags are hard-coded in the GN4 applications, therefore, they are always available. The user defined tags and styles are stored in the GNML style libraries, which are linked to a format, associated to a text. Thus, the link to a format must be persistent, otherwise, the GN4 justification engine will not find tags, and the text will cause justification errors.

•It is centralized: The tags in text are processed and interpreted when a text is displayed or printed. The built-in tags are hard-coded in the GN4 applications, therefore, they are always available. The user defined tags and styles are stored in the GNML libraries, which are linked to a format, associated to a text. Thus, the link to a format must be persistent, otherwise, the interpreter will not find tags, and the text will cause justification errors.