Independent Consultant, Cambridge, UK
Abstract: The usual category codes give TEX its familiar backslash and braces input syntax. With Active TEX, all characters are active. This gives the macro programmer complete freedom in defining the input syntax. It also provides a powerful programming environment.
The dot input syntax, like TROFF, uses a period at the start of the line as an escape character. However, its underlying element, attribute and content structure is based on SGML. It is both easy to use and easy to program for. This new syntax will be described and demonstrated.
All manner of problems connected with TEX disappear when Active TEX packages are used. For example, all input errors can be detected and corrected before they cause a TEX error message. This will make TEX accessible to many more users.