Editing Interleaf (section)

=== TPS ===

TPS (later renamed to "Interleaf 5," up through "Interleaf 7") was an integrated, networked text-and-graphics document creation system initially designed for technical publishing departments. Versions after its first release in 1984 added instantaneous updating of page numbering and reference numbers through multi-chapter and multi-volumes sets, increased graphics capabilities, automatic index and table of content generation, hyphenation, equations, "microdocuments" that recursively allowed fully functional whole document elements to be embedded in any document, and the ability to program any element of a document (a capability the company called "Active Documents"). Interleaf software was available in many languages including Japanese text layout.

TPS was a structured document editor. That is, it internally treated a document as a set of element classes, each with its own set of properties. Classes might include common document elements such as a body, paragraphs, titles, subheadings, captions, etc. Authors were free to create any set of elements and save them as a reusable template. The properties of a class &mdash; its font size, for example &mdash; could be changed and automatically applied to every instance of that class. If this caused a change in pagination &mdash; increasing the font size could change where the page breaks were &mdash; the software would update the screen quickly enough for the author to continue typing, including altering all of the cross-references that the author may have inserted; this WYSIWYG capability was a competitive advantage for the company. The structured nature of the documents also enabled TPS to provide ''conditional document assembly'', a feature that enabled users to "tag" document elements with [[metadata]] about them, and then automatically assemble versions of the document based upon those tags. For example, an aircraft manufacturer might tag paragraphs with the model number of the planes to which they applied and then assemble versions of the documentation specific to each model.

The fact that it created structured documents enabled Interleaf to add its Active Document capabilities in the early 1990s. Just as [[JavaScript]] enables contemporary software developers to add functionality and "intelligence" to Web documents, Interleaf used LISP to enable document authors and engineers to enhance its authoring electronic publishing systems. Any document element could be given new "[[Method (computer programming)|methods]]" (capabilities), and could respond to changes in the content or structure of the document itself. Typical applications included documents that automatically generated and updated charts based upon data expressed in the document, pages that altered themselves based on data accessed from databases or other sources, and systems that dynamically created pages to guide users through complex processes such as filling out insurance forms.