Adobe 65030365 Developer's Guide - Page 40

3 Processing instructions • FrameMaker represents external cross-references in XML with a variation of the ID/ IDREF model. Instead of an IDREF attribute, it uses a srcfile attribute whose value identifies the file containing the source element as well as the value of its ID attribute. • FrameMaker and markup have different views of what constitutes an internal or external cross-reference. In FrameMaker, a cross-reference to a different file is always an external cross-reference. In markup, cross-references to different entities in a single document are always internal cross-references. So cross-references between components in a FrameMaker book are considered external, but cross-references between the text entities that correspond to those components are internal, since the entire book translates to a single XML or SGML document. • XML and SGML allow a single attribute value to link several sources. FrameMaker requires a separate cross-reference for each citation. For information on creating cross-references in FrameMaker documents, see the FrameMaker User Guide. For information on translating cross-references to markup, see Chapter 20, "Translating Cross-References." Processing instructions Markup data can include processing instructions to modify the treatment of a document in some system-specific manner. FrameMaker translates most processing instructions as markers in your FrameMaker document. It also defines a small number of special processing instructions for handling FrameMaker markers, books, and book components. You can use the FrameMaker Developer's Kit (FDK) to handle other processing instructions when reading markup documents, but not when creating an EDD from a DTD. For information on handling processing instructions, see Chapter 17, "Translating Entities and Processing Instructions," and Chapter 24, "Processing Multiple Files as Books." Parameter entity declarations A DTD can use parameter entities as references to declaration content that is repeated in different statements. When FrameMaker reads a DTD with parameter entities, it expands them out to the full content of the reference. Any declarations that use a parameter entity will translate with the correct content, but the resulting EDD does not retain the parameter entity declaration nor the parameter entity itself. When you create an EDD, you can use FrameMaker variables as references to repeated content. When FrameMakertranslates the EDD to a DTD, it does not convert these variables to corresponding parameter entities. A General Comparison of Markup and FrameMaker Documents 22