p:split-sequence (3.1) 

Summary

<p:declare-step type="p:split-sequence">
  <input port="source" primary="true" content-types="any" sequence="true"/>
  <output port="matched" primary="true" content-types="any" sequence="true"/>
  <output port="not-matched" primary="false" content-types="any" sequence="true"/>
  <option name="test" as="xs:string" required="true"/>
  <option name="initial-only" as="xs:boolean" required="false" select="false()"/>
</p:declare-step>

The p:split-sequence step takes a sequence of documents on its source port and divides this into two sequences, based on the evaluation expression in the test option and the value of the initial-only option.

Ports:

Options:

Description

The p:split-sequence step works like a switch in a train marshalling yard. A train with document wagons approaches the switch. The switchman has instructions to send a wagon in one direction or the other, depending on the contents of the document. In more technical terms:

• The p:split-sequence step takes a sequence of documents on its source port.

• For every document, the XPath boolean expression in the test option is evaluated. During this evaluation, the document is the context item (accessible with the dot operator .).

  The position() and last() functions are available to get the position of the document in the sequence and the size of the sequence (see also the Using the position() and last() function example).

• If the initial-only option is false:

  • If the result of the test option evaluation is true, the document appears on the matched port.

  • If the result of the test option evaluation is false, the document appears on the not-matched port.

• If the initial-only option is true:

  • If the result of the test option evaluation is true, the document appears on the matched port, until a document appears for which this expression evaluates to false.

  • The first document for which the test option evaluation is false and all subsequent documents are sent to the not-matched port.

  In other words: it only writes the initial series of matched documents (which may be empty) to the matched port. All other documents are written to the not-matched port, irrespective of the outcome of the test option evaluation.

Examples

<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0">

  <p:input port="source" sequence="true">
    <fruit name="banana" color="yellow"/>
    <fruit name="orange" color="orange"/>
    <fruit name="lemon" color="yellow"/>
    <fruit name="cauliflower" color="white"/>
  </p:input>
  <p:output port="result"/>

  <p:split-sequence test="/*/@color eq 'yellow'"/>

  <p:wrap-sequence wrapper="matched-documents"/>

</p:declare-step>

<matched-documents>
   <fruit color="yellow" name="banana"/>
   <fruit color="yellow" name="lemon"/>
</matched-documents>

<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0">

  <p:input port="source" sequence="true">
    <fruit name="banana" color="yellow"/>
    <fruit name="orange" color="orange"/>
    <fruit name="lemon" color="yellow"/>
    <fruit name="cauliflower" color="white"/>
  </p:input>
  <p:output port="result"/>

  <p:split-sequence test="/*/@color eq 'yellow'"/>

  <p:wrap-sequence wrapper="not-matched-documents">
    <p:with-input pipe="not-matched"/>
  </p:wrap-sequence>

</p:declare-step>

<not-matched-documents>
   <fruit color="orange" name="orange"/>
   <fruit color="white" name="cauliflower"/>
</not-matched-documents>

<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0">

  <p:input port="source" sequence="true">
    <fruit name="banana" color="yellow"/>
    <fruit name="orange" color="orange"/>
    <fruit name="lemon" color="yellow"/>
    <fruit name="cauliflower" color="white"/>
  </p:input>
  <p:output port="result"/>

  <p:split-sequence test="/*/@color eq 'yellow'" initial-only="true"/>

  <p:wrap-sequence wrapper="matched-documents"/>

</p:declare-step>

<matched-documents>
   <fruit color="yellow" name="banana"/>
</matched-documents>

<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0">

  <p:input port="source" sequence="true">
    <fruit name="banana" color="yellow"/>
    <fruit name="orange" color="orange"/>
    <fruit name="lemon" color="yellow"/>
    <fruit name="cauliflower" color="white"/>
  </p:input>
  <p:output port="result"/>

  <p:split-sequence test="position() eq last()"/>

  <p:wrap-sequence wrapper="matched-documents"/>

</p:declare-step>

<matched-documents>
   <fruit color="white" name="cauliflower"/>
</matched-documents>

Additional details

• p:split-sequence preserves all document-properties of the document(s) appearing on its source port.

Errors raised

Reference information

This description of the p:split-sequence step is for XProc version: 3.1. This is a required step (an XProc 3.1 processor must support this).

The formal specification for the p:split-sequence step can be found here.

The p:split-sequence step is part of categories:

• Standard XProc steps

• Miscellaneous

The p:split-sequence step is also present in version: 3.0.