201820192020 20212022202320242025 the Contributors to the XProc 3.1 Standard Step Library specifications XProc/specification XProc Next XML Norman Walsh Achim Berndzen Gerrit Imsieke Erik Siegel This specification describes the p:css-formatter and p:xsl-formatter steps for XProc 3.1: An XML Pipeline Language. This specification was published by the XProc Next Community Group. It is not a W3C Standard nor is it on the W3C Standards Track. Please note that under the W3C Community Contributor License Agreement (CLA) there is a limited opt-out and other conditions apply. Learn more about W3C Community and Business Groups. If you wish to make comments regarding this document, please send them to xproc-dev@w3.org. (subscribe, archives). This document is derived from XProc: An XML Pipeline Language published by the W3C. This draft is the “editor’s working draft” and may continue to evolve.

This specification describes the p:css-formatter and p:xsl-formatter XProc steps. A machine-readable description of these steps may be found in steps.xpl. Familarity with the general nature of steps is assumed.

The p:css-formatter step applies formatting to an XML or HTML document. The output of this step is often, but not necessarily, a PDF document. The document on the source port is formatted using one or more CSS stylesheets. The content-type of the output is controlled by the content-type option. This option specifies a media type as defined by . It is a dynamic error if a supplied content-type is not a valid media type of the form “type/subtype+ext” or “type/subtype”. The option may include media type parameters as well (e.g. "application/someformat; charset=UTF-8"). The use of media type parameters on the content-type option is implementation-defined. If the content-type option is not specified, the output type is implementation-defined. The default should be PDF. It is a dynamic error if the requested content-type is not supported. If one or more stylesheets are provided on the stylesheet port, they should be used. The precise way that the p:css-formatter step selects stylesheets is implementation-defined. Because CSS stylesheets may have import statements that rely on relative URI references, it may be more convenient for authors and implementors to allow stylesheets to be specified as a list of URIs (in, for example, one of the parameters). A formatter may take any number of optional rendering parameters via the step's parameters; such parameters are defined by the CSS implementation used and are implementation-defined. The CSS level and the particular CSS features supported by p:css-formatter are implementation-defined. It is a dynamic error if the requested document cannot be produced. No document properties are preserved.

The p:xsl-formatter step receives an document and renders the content. The content-type of the output is controlled by the content-type option. This option specifies a media type as defined by . It is a dynamic error if a supplied content-type is not a valid media type of the form “type/subtype+ext” or “type/subtype”. The option may include media type parameters as well (e.g. "application/someformat; charset=UTF-8"). The use of media type parameters on the content-type option is implementation-defined. If the content-type option is not specified, the output type is implementation-defined. The default should be PDF. It is a dynamic error if the requested content-type is not supported. A formatter may take any number of optional rendering parameters via the step's parameters; such parameters are defined by the XSL implementation used and are implementation-defined. The output of this step is a document containing the result of processing. This is often, but not necessarily, a PDF document. It is a dynamic error if the requested document cannot be produced. No document properties are preserved.

This step can raise dynamic errors. A dynamic error is one which occurs while a pipeline is being evaluated. Examples of dynamic errors include references to URIs that cannot be resolved, steps which fail, and pipelines that exhaust the capacity of an implementation (such as memory or disk space). For a more complete discussion of dynamic errors, see . If a step fails due to a dynamic error, failure propagates upwards until either a p:try is encountered or the entire pipeline fails. In other words, outside of a p:try, step failure causes the entire pipeline to fail. The following errors can be raised by this step:

Conformant processors must implement all of the features described in this specification except those that are explicitly identified as optional. Some aspects of processor behavior are not completely specified; those features are either implementation-dependent or implementation-defined. An implementation-dependent feature is one where the implementation has discretion in how it is performed. Implementations are not required to document or explain how implementation-dependent features are performed. An implementation-defined feature is one where the implementation has discretion in how it is performed. Conformant implementations must document how implementation-defined features are performed.

The following features are implementation-defined:

Glossary needs to be generated This specification includes by reference a number of ancillary files. An XProc step library for the declared steps.