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The Extensible Style Language (XSL)

XSL is a high level stylesheet language designed for the Web community.

It provides functionality beyond CSS (e.g. element reordering).

CSS will be used to display simply-structured XML documents

XSL will be used where more powerful formatting capabilities are required or for formatting highly structured information such as XML structured data or XML documents that contain structured data.

XSL is based on Document Style Semantics and Specification Language (DSSSL)

XSL allows:

Formatting of source elements based on ancestry/descendency, position, and uniqueness

The creation of formatting constructs including generated text and graphics

The definition of reusable formatting macros

Writing-direction independent stylesheets

An extensible set of formatting objects

XSL supports all of the functionality of CSS so that an accurate mechanical translation from CSS to XSL is possible.

It allows a migration path HTML/CSS object model compatibility

XSL provides a set of HTML/CSS core flow objects with HTML attributes and CSS properties as characteristics

XSL stylesheets are similar to those used in CSS

They specify as set of rules that are applied (or flow) throughout the tree structure of a document

Here is an example taken from the W3C's "Note on XSL": 

	<xsl>
  <rule>
    <root/>

    <HTML>
      <BODY>
        <children/>
      </BODY>
    </HTML>
  </rule>
  
  <rule>
    <target-element type="orders"/>

    <DIV font-size="14pt" font-family="serif">
      <children/>
    </DIV>
  </rule>

  <style-rule>
    <target-element type="customer"/>

    <apply font-weight="bold"/>
  </style-rule>
</xsl>

The basic ideas of XSL are:

XSL should be straightforwardly usable over the Internet

XSL should be expressed in XML syntax

XSL should provide a declarative language to do all common formatting tasks

XSL should provide an ÒescapeÓ into a scripting language to accommodate more sophisticated formatting tasks and to allow for extensibility and completeness

XSL will be a subset of DSSSL with the proposed amendment

A mechanical mapping of a CSS stylesheet into an XSL stylesheet should be possible

The number of optional features in XSL should be kept to a minimum

XSL stylesheets should be human-legible and reasonably clear

The XSL design should be prepared quickly

XSL stylesheets shall be easy to create

Terseness in XSL markup is of minimal importance

This page prepared by Howard Rosenbaum Last update: 11.12.98
You are here: http://memex.lib.indiana.edu/hrosenba/www/Pres/IULOG/tech3.html


Onwards!