Spine, Doc Reform - SiSU Markup
Ralph Amissah (2008-05-22)

SiSU Description

1. SiSU Description

SiSU is an object-centric, lightweight markup based, document structuring, parser, publishing and search tool for document collections. It is command line oriented and generates static content that is currently made searchable at an object level through an SQL database. Markup helps define (delineate) objects (primarily various types of text block) which are tracked in sequence, substantive objects being numbered sequentially by the program for object citation.

Summary. An object is a unit of text within a document the most common being a paragraph. Objects include individual headings, paragraphs, tables, grouped text of various types such as code blocks and within poems, verse. Objects have properties and attributes, of particular significance are headings and their levels which provide document structure. A heading is an object with a heirarchical value, that conceptually contains other objects (such as paragraphs and possibly sub-headings etc.). Objects are tracked sequentially as they relate to each other object within a document and substantive objects are numbered sequentially, for citation purposes. Notably footnotes are not objects in themselves, rather belonging to the object from which they are referenced, and following their own numbering sequence. From heading objects (linked) tables of content may be generated, and if additional metadata is provided book type indexes can be generated that link back to the objects to which they relate.

Unpacking this a bit further. SiSU as a concept independent of its markup language and the parsers that have been implemented, is based on the following ideas:

Object-Centricity. On objects: In SiSU objects are the fundamental unit from which larger constructs within a document and the document itself is built. Breaking the document into objects provides interesting possibilities.

Objects are fundamental building blocks: Conceptually within SiSU, objects are the building blocks or individual units of construction of a document. Objects are usually blocks of text, the most common of which is the paragraph, other examples include: individual headings, tables, grouped text of various types which include code blocks and verse within poems, ... and as mentioned an object could also, for example, be an image. Objects can be formatted and placed as needed, providing flexibility and enabling multiple types of representation across disperate formats and text recepticle, examples including html, epub, latex (in the past mind-maps) and sql (populated at an object level, and thereby providing search with that degree of granularity).

Sequential. Objects have sequence: That objects have sequence, goes largely without saying, this follows authorship, it is part of the definition of a document and how a document is written to convey meaning.

Object Numbers & Citation. Substantive objects are numbered for citation purposes: Most objects within a document are meant by the author to be a substantive part of the document. All such objects are numbered sequentially and can be referenced thereby for citation purposes. Object numbers provide the possibility of citing/locating text precisely across different document formats and different languages (assuming the document has been translated). For search it also makes it possible to identify precisely where search criteria is met within in each document in the form of an index or to view those precise text objects before deciding which documents are of interest. Additionally the use of objects (and that objects are numbered) frees the possibility to represent the document in the manner considered most suitable to a specific document format wilst retaining its structural (and citation) integrity).

Characteristics. Objects have properties and attributes: Objects have properties (and may have attributes). By properties I here refer to the fundamental type of object, be it a heading, a paragraph, table, verse etc. Attributes extend further and may include other things that one might wish to associate with the object (examples not necessarily currently available/ implemented in SiSU might include, formatting whether it is indented, or metadata e.g. the associated language, or programming language for a code block)

Document structure. Heading objects hold documents structure: Heading objects hold documents structure through their heading level property. The types of document of interest to SiSU have structure that is captured by the heading level property. Headings are individual objects like any other with the additional properties that (i) they may be regarded as containing the other objects following them sequentially (until the next heading of a similar or higher level), heading objects may include other headings (sub-headings), and (ii) that they have a heirarchy, the root “heading” being the document title.
A complication was intruduced to provide greater flexibility across document output formats. Headings have two sets of levels, the level under which substantive text occurs, this would be a chapter or segment level, and above that in the heirarchy if needed are document section separators, book, section, part.

Non-objects Most but not all parts of a document are treated as objects. Notably footnotes are not objects in themselves, rather belonging to the object from which they are referenced, and following their own numbering sequence. From heading objects (linked) tables of content may be generated, and if additional metadata is provided book type indexes can be generated that link back to the objects to which they relate.

The Document Header. SiSU document have headers which contain document metadata, at a minimum the document title and author. In addition the document header may contain markup instruction (e.g. how to identify headings within the document, in which case those headings need not be found and treated accordingly)

SiSU parsers have now been implemented in different programming paradigms and languages a couple of times, the chosen markup has been left unchanged though the document headers have been modified.

This is the core of sisu, beyond which there is more but largely in the form of choices based on ... existing output formats and of implementation detail, deciding what attributes of objects, or within objects should be supported, extending markup to allow for the generation of book indexes from if tagging provided.

1.1. Older Descriptions

Here is a description that has been used for the original sisu (scribe):

With minimal preparation of a plain-text (UTF-8) file, using sisu markup syntax in your text editor of choice, SiSU can generate various document formats, most of which share a common object numbering system for locating content, including plain text, HTML, XHTML, XML, EPUB, OpenDocument text (ODF:ODT), LaTeX, PDF files, and populate an SQL database with objects (roughly paragraph-sized chunks) so searches may be performed and matches returned with that degree of granularity. Think of being able to finely match text in documents, using common object numbers, across different output formats (same object identifier for pdf, epub or html) and across languages if you have translations of the same document (same object identifier across languages). For search, your criteria is met by these documents at these locations within each document (equally relevant across different output formats and languages). To be clear (if obvious) page numbers provide none of this functionality. Object numbering is particularly suitable for “published” works (finalized texts as opposed to works that are frequently changed or updated) for which it provides a fixed means of reference of content. Document outputs can also share provided semantic meta-data.

1.2. ...

SiSU is less about document layout than it is about finding a way using little markup to construct an abstract representation of a document that makes it possible to produce multiple representations of it which may be rather different from each other and used for different purposes, whether layout and publishing, scrollworthy online viewing/ reading, or content search. To be able to take advantage from its minimal preparation starting point of some of the strengths of rather different established ways of representing documents for different purposes, whether for search (relational database, or indexed flat files generated for that purpose whether of complete documents, or say of files made up of objects), online or other electronic viewing (e.g. html, xml, epub), or paper publication (e.g. pdf via latex)...

The solution arrived at is to extract structural information about the document (document sections and headings within the document, available through pattern matching or markup) and tracking objects (which primarily are defined units of text such as paragraphs, headings, tables, verse, etc. but also images) which can be reconstituted as the same documents with relevant object identification numbers so text (objects) can be referenced across different output formats and presentations.

SiSU generates tables of content, and through its markup the means for metadata to be provided for the generation of book style indexes for a document (that again due to document object numbers are the same and equally relevant across all document formats). Per document classifying/organizing metadata can also be provided for automated document curation.

... there have also been working experiments with sisu markup source, two way conversion/representation of sisu document markup source in mind-mapping (software kdissert was used for its strong focus on producing documents (now apparently called semantik)); also po4a software for translators has been used successfuly in its regular text mode for sisu markup in translation, (which is more an attribute of po4a than of sisu, but) which is of interest due to sisu/spine's object citation numbering being available across translations. Open Document Format text (odf:odt), has been an output, but much more interesting (and requested by potential users of sisu/spine) would be the ability of a word processor to save text/a document in sisu markup, making alternative document processing and presentations with sisu possible.

also worth mention, in the relatively long history of this project, there has been work done on extracting hash representations of each object, that could hypothetically be shared to prove the content of a document without sharing its content, or of identifying which objects change; these hashes can also be used as unique identifiers in a database or as identifying filenames if individual objects are saved.

SiSU has evolved, the current implementation focuses on one primary use-case, books and literary writings. However the concept on which it is based has wider application. Here is a prevously posted souvenir from my encounter with an IBM software evaluator in London June 2004 that came about through a chance encounter with an IBM manager at a Linux Expo, who was curious about my interest in Gnu/Linux with my legal background... on hearing that I also wrote software, he suggested, maybe IBM should have a look at it. I was interested, the meeting was set up... with an IBM, Software Innovations evaluator<br>His response after the meeting:

Good to meet with you today, I was very impressed with your software.
[colleague's name (also posted to an IBM colleague)] - in summary - Ralph has built an application that runs on linux and takes ASCII documents and pulls them apart in to the smallest constituent parts, storing them as XML, PDF and HTML, the HTML are hyperlinked up so the document can be browsed in its full form. the format and text data created is stored in a database.<br>This has potential in any place that needs the power of full text search whilst holding the structural concepts of the document i.e. legal, pharma, education, research.. which ones we need to figure out, ...”

Special interest was expressed in the search implications of SiSU. To paraphrase, the company has document management systems dealing with hundreds of thousands of texts, these tell you which documents match your search criteria, but cannot inform you where within a text these matches were found without opening the documents. This is achieved through defining document objects and making them the building block of the document, trackable document objects (that can be placed back in the context of the document or corpus of documents if part of a collection). SiSU's early design was to - abstract documents to their structure, and identified objects, numbered in a citable way (as pointed out document object hashes can be of use for the purpose).

1.3. SiSU Spine

SiSU Spine is the new generator for documents prepared in sisu markup, written in D as opposed to the original sisu which was first shared in Ruby.

Spine code has not as yet been made publicly available.

As compared with the original sisu generator sisu spine:

- Spine uses the same document markup for the document body, but uses yaml for document headers (which contains document metadata and configuration details), the original sisu has a bespoke markup for headers.

- Spine (written in D) is considerably faster at generating native output than sisu (written in Ruby), on last test at least 60 times faster (what took 1 minute takes 1 second; 1 hour a minute :-) (admittedly some time ago, ruby has been getting faster, hopefully this is not over over promising).

- Spine produces fewer document outputs types than sisu (html, epub, (odt, latex) and populates sql db for search)

- As regards non-native output, so far Spine has greater separation of what it does and largely leaves calling the external program to the user, e.g.: latex output is a native output in the sense that it is generated directly by spine, but the pdfs that can be produced from these are produced through use of an external program xelatex, which produces fine output but is a very much slower process.

- (where both produce the same output type, generally) Spine generally produces more up to date output format representations.

License: GPL 3 (part of SiSU documentation)

≅ SiSU Spine ፨ (object numbering & object search)

(web 1993, object numbering 1997, object search 2002 ...) 2024