One Strategy for Xsl Overrides in ePublisher Formats

Abstract

One great feature of the older WebWorks Publisher was the ability to simply override ordinary formatting by typing output directly into a Style object's Macro tab. This document presents a solution for achieving this functionality on the ePublisher Platform.

Introduction

The ePublisher Platform works very well with technologies that implement a style-based processing model. In Word and !FrameMaker, this is usually achieved through the use of document templates. On the ePublisher Platform, styles are used to delineate the borders of a given document's content. The ePublisher Formats are heavily tied to the ePublisher Pro User Interface. As such, the XSL files which implement a given ePublisher Format's output are extremely verbose, with a moderately high level of complexity which advanced XSL user's may find challenging. This document outlines a simple approach to take a little knowledge of XSL and use it to implement your own output for a given style.

Getting Started

First, create a new ePublisher Project based on your chosen format. Once the project has been created, create a Format override. Refer to the following link:

http://www.webworks.com/Technical_Assistance/Tech_Notes/Common/EX_ePub_Project_Format_Overrides.shtml

In particular, you need to override Transforms/pages.xsl and Transforms/content.xsl.

Changes to pages.xsl

Open pages.xsl and make the following changes:

1. Add the following to the <xsl:include /> area:

   <xsl:include href="wwformat:Includes/paragraphs.xsl" />

2. Add the following line to the VarTransformChecksums variable:

   <xsl:value-of select="concat(',', wwuri:AsFilePath('wwformat:Includes/paragraphs.xsl'), ':', wwfilesystem:GetChecksum(wwuri:AsFilePath('wwformat:Includes/paragraphs.xsl')))" />

3. Save the changes and close pages.xsl.

Changes to content.xsl

Open content.xsl and make the following changes:

1. Search for <xsl:template name="ParagraphTextRuns">.

2. Change the line as follows:

   <xsl:template name="ParagraphTextRuns" match="wwdoc:TextRun" mode="wwmode:content">

3. Save the changes to content.xsl and close.

Adding Includes/paragraphs.xsl

1. In the named area of your Format override, add a directory called, "Includes" (Formats/Dynamic HTML/Includes, for example).
2. Download paragraphs.xsl and put it into the new "Includes" directory.

Make Changes

The paragraphs.xsl file that you downloaded matches a paragraph with the stylename, SectionQuote and places a HTML <div> tag around it with a style attribute. This is just an example. You will probably want to change the @stylename = 'SectionQuote' to refer to the style you want to process.

Understanding What's Happening

The most important part of this strategy is that it works because you are creating a better match expression. The default content.xsl already includes a match template for wwdoc:Paragraph. In this strategy, we simply override that default template by including one with a better match expression:

<xsl:template match="wwdoc:Paragraph[@stylename = 'SectionQuote']">
 ...
</xsl:template>

The XSL processor will only apply-templates once for the best match. So in this case, if the stylename is SectionQuote, your match template will be applied instead of the default template.

Notice that the <xsl:template></xsl:template> included in paragraphs.xsl passes along a number of parameters. It is important to pass these parameters along if you want to pass the processing flow back to the base Format. Keep in mind however, you might divert the flow altogether for processing the contents of the paragraph by introducing your own mode, for example.

Overriding Other Types of Styles

You can use a similar approach for other types of styles. For example, you might repeat the step to create a Includes/characters.xsl. In such a case, the better match expression would be for the wwdoc:TextRun element. For example:

<xsl:template match="wwdoc:TextRun[@stylename = 'BoldItalic']">
 ...
</xsl:template>

However, because other such approaches might be different depending on the Format you are using, specifics are not covered here.

Another Override Example - Markers

See http://wiki.webworks.com/DevCenter/Projects/WebWorksHelp/UsingTopicIdentifiers/Discussion