Separation of presentation and content

Separation of presentation and content (or "separate content from presentation", a special case of the form and content
Form and content
In art and art criticism, form and content are considered distinct aspects of a work of art. The term form refers to the work's style, techniques and media used, and how the elements of design are implemented. Content, on the other hand, refers to a work's essence, or what is being depicted....

principle) is a common idiom

Idiom

Idiom is an expression, word, or phrase that has a figurative meaning that is comprehended in regard to a common use of that expression that is separate from the literal meaning or definition of the words of which it is made...

, a design philosophy, and a methodology applied in the context of various publishing technology

Publishing (disambiguation)

Publishing may refer to:Media:* Publishing any form of media** Desktop publishing, design and preparation of media on a desktop computer for publishing** Electronic publishing of electronic media*** Software publishing business...

disciplines, including information retrieval

Information retrieval

Information retrieval is the area of study concerned with searching for documents, for information within documents, and for metadata about documents, as well as that of searching structured storage, relational databases, and the World Wide Web...

, template processing

Template processor

A template processor is software or a software component that is designed to combine one or moretemplates with a data model to produceone or more result documents...

, web design

Web design

Web design is the process of planning and creating a website. Text, images, digital media and interactive elements are used by web designers to produce the page seen on the web browser...

, web development

Web development

Web development is a broad term for the work involved in developing a web site for the Internet or an intranet . This can include web design, web content development, client liaison, client-side/server-side scripting, web server and network security configuration, and e-commerce development...

, word processing

Word processing

Word processing is the creation of documents using a word processor. It can also refer to advanced shorthand techniques, sometimes used in specialized contexts with a specially modified typewriter.-External links:...

, desktop publishing

Desktop publishing

Desktop publishing is the creation of documents using page layout software on a personal computer.The term has been used for publishing at all levels, from small-circulation documents such as local newsletters to books, magazines and newspapers...

, and model-driven development. It is a specific instance of the more general philosophy, separation of concerns

Separation of concerns

In computer science, separation of concerns is the process of separating a computer program into distinct features that overlap in functionality as little as possible. A concern is any piece of interest or focus in a program. Typically, concerns are synonymous with features or behaviors...

History

The first person known to have expressed need for such a separation was William W. Tunnicliffe

William W. Tunnicliffe

William W. Tunnicliffe is credited by Charles Goldfarb as being the first person to articulate the idea of separating the definition of formatting from the structure of content in electronic documents .In September 1967, during a meeting at the Canadian Government Printing Office, Tunnicliffe...

Intended meaning

When invoked as an idiom, the underlying concept is to make a distinction between the actual meaning of a document, and how this meaning is presented to its readers. A common example is the em element in HTML, to denote emphasis. While emphasis is part of the content of the document, its presentation may be in an oblique

Oblique

Oblique may refer to:*Oblique angle, in geometry, an angle that is not a multiple of 90 degrees*Oblique angle, synonym for Dutch angle, a cinematographic technique*Oblique , by jazz vibraphonist Bobby Hutcherson...

font style, but one need not necessarily imply the other: for example, emphasis in text that is already oblique should in fact be printed in some other font style or weight (e.g., normal again or in boldface) that is distinct from that of the text it appears in; conversely, oblique text need not imply emphasis—it could be used to style a preface, for example. Moreover, notice that the foregoing sentence assumes that the output mode is visual; but if the mode were audio, the indication of the intended meaning (emphasis) could be achieved by formatting the em words with a louder or higher-pitched voice by the text-to-speech synthesizer

Speech synthesis

Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware...

. Separation of content and presentation means that markup is always used for document structure, never for presentation (which is properly the job of tools such as CSS).

Machine readability

The general aim of separation of presentation and content is machine readability, that is, making it possible for machines to detect meaning or intent. (The machine readability is then a means to desired ends, as discussed below.) For example, a human being reading a document has little trouble to grab from context that an oblique rendering in one place would be emphasized text, but in another place is a title of a book. However, as robots and crawlers have more difficulty with this task, separation of presentation and content generally aids in their distinguishing of such things which are presented in the same way, but have a different meaning—or have the same meaning, but are presented in a different way.

Machine readability allows affordably serving the information to a wider variety of users (in a presentation that they can understand), where users may be humans or machines. This requires the ability to recast abstractions in new instances quickly and cheaply (that is, without time-consuming reworking), which generally requires automation rather than person-hours of labor. For example:

The ability to deliver the same information in different media, and to change the medium quickly and cheaply; and within one medium, to change instances easily
- To serve the same message to different users:
  - as printed display (for technophobes or for users with contextual desire for print)
    - as printed display with the typesetting
      Typesetting
      Typesetting is the composition of text by means of types.Typesetting requires the prior process of designing a font and storing it in some manner...
      
      recast into various graphic designs without time being spent on any manual reworking of the content (a good example is given at CSS Zen Garden
      CSS Zen Garden
      The CSS Zen Garden is a World Wide Web development resource. The goal of the site is to showcase what is possible with CSS-based design. Style sheets contributed by graphic designers from around the world are used to change the visual presentation of a single HTML file, producing hundreds of...
      
      )
  - as online visual display (for most users in most instances)
    - as online visual display in various graphic designs
  - as online audio (for blind users or for sighted users with contextual desire for audio)
  - as braille (for blind users)
  - as input to an API (for users that are machines)
    - The other machines can then take the information and do further transformations or actions. These may be ones that people cannot do (or cannot do quickly and cheaply), but machines can do (and can do [more] quickly and [more] cheaply). For example:
      - Take a book and translate it into another natural language
      - Take audio of speech and translate it into another natural language
      - Take audio of speech and transcribe it for reading (for deaf users or for hearing users who want transcription of voicemail into e-mail or IM)
      - Take the data contained in an entire library and search through it for ABC-XYZ, then turn every instance of ABC blue, and serve every instance of XYZ to a machine that will categorize it

Common terms

There are a number of common terms used to describe these two separate dimensions of communication, which include:

Semantic : logic, information, ontology, semantics, data, outline, model, message, content

Aesthetic (or parsing-related): graphics, design, layout, style, visualization, view, medium, presentation

Possibility and degrees of separation

In communication design

Communication design

Communication design is a mixed discipline between design and information-development which is concerned with how media intermission such as printed, crafted, electronic media or presentations communicate with people...

, the message is the content and the medium is the tools to deliver that message. In the book Understanding Media
Understanding Media: The Extensions of Man
Understanding Media: The Extensions of Man is a pioneering study in media theory written by Marshall McLuhan. In it McLuhan proposed that media themselves, not the content they carry, should be the focus of study...

, Marshall McLuhan

Marshall McLuhan

Herbert Marshall McLuhan, CC was a Canadian educator, philosopher, and scholar—a professor of English literature, a literary critic, a rhetorician, and a communication theorist...

stated that "The medium is the message

The medium is the message

"The medium is the message" is a phrase coined by Marshall McLuhan meaning that the form of a medium embeds itself in the message, creating a symbiotic relationship by which the medium influences how the message is perceived.- Publications :...

", which has since been the subject of much debate. One interpretation is that the choice of medium (presentation tools) affects the (presentation content) message. It is possible for the choice of content and choice of medium to affect the quality of the presentation

Presentation

Presentation is the practice of showing and explaining the content of a topic to an audience or learner. Presentations come in nearly as many forms as there are life situations...

, meaning how well a message may be received. The degree that content may be separated from presentation depends on how much the quality of the medium affects the quality of the message. In many cases, the possibility and degrees of separation are as subjective as the content itself.

History

Intended meaning

Machine readability

Common terms

Possibility and degrees of separation

See also