when

`when`
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`when`

Table of Contents

Declaration
Related GitHub issue(s)
Sample usage
Commentary

Element context(s)

phase

This attribute is optional and activates the phase when its expression matches.

Clause 5.4.13 (phase element)
The string #ANY denotes that the active phase is selected using the method given in [Clause 5.5.22] and if no active phase is selected, then all patterns are active.

Clause 5.5.22 (when attribute)
The when attribute is an expression evaluated to a Boolean in the context of the instance document root. If the expression evaluates to true(), then its parent phase becomes active. The first such phase declared in schema document order shall be the active phase.
This behaviour shall not apply to subordinate documents, that is those selected by the documents attribute [...].

Declaration

phase =
     element phase {
         attribute id { xsd:ID },
         attribute from { text }?,
         attribute when { pathValue }?,
         rich,
         (foreign & inclusion* & (p*, let*, active*))
     }

Related GitHub issue(s)

Enhancement for sch:phase - @when

Sample usage

Example 11. from attribute

Given this instance document:

<foo>
<blort wibble='1'/>
<bar><blort wibble='2'/><blort wibble='3'/></bar>
</foo>

and this schema:

<sch:schema>
  <sch:phase id='foo' when='/foo'>
    <sch:active pattern='wibble-1'/>
  </sch:phase>
  <sch:phase id='wibble' when='//@wibble'>
    <sch:active pattern='wibble-2'/>
  </sch:phase>
  <sch:phase id='bar' when='/foo/bar'>
    <sch:active pattern='wibble-3'/>
  </sch:phase>
  <sch:pattern id='wibble-1'>
    <sch:rule context='//blort[@wibble]'>
      <sch:report test='@wibble'><sch:value-of select='@wibble'/></sch:report>
    </sch:rule>
  </sch:pattern>
  <sch:pattern id='wibble-2'>
    <sch:rule context='//blort[@wibble]'>
      <sch:report test='@wibble'><sch:value-of select='@wibble/..'/></sch:report>
    </sch:rule>
  </sch:pattern>
  <sch:pattern id='wibble-3'>
    <sch:rule context='//blort[@wibble]'>
      <sch:assert test='normalize-space(@wibble)'>value must not be empty</sch:assert>
    </sch:rule>
  </sch:pattern>
</sch:schema>

all instances of the when attribute match when evaluated against the document instance, but only the first matching phase in document order (wibble-1) is selected:

<svrl:schematron-output xmlns:svrl="http://purl.oclc.org/dsdl/svrl" phase="foo">
  <svrl:active-pattern id="wibble-1"/>
  <svrl:fired-rule context="//blort[@wibble]"/>
  <successful-report xmlns="http://purl.oclc.org/dsdl/svrl" location="/Q{}foo[1]/Q{}blort[1]" test="@wibble">
    <svrl:text>1</svrl:text>
  </successful-report>
  <successful-report xmlns="http://purl.oclc.org/dsdl/svrl" location="/Q{}foo[1]/Q{}bar[1]/Q{}blort[1]" test="@wibble">
    <svrl:text>2</svrl:text>
  </successful-report>
  <successful-report xmlns="http://purl.oclc.org/dsdl/svrl" location="/Q{}foo[1]/Q{}bar[1]/Q{}blort[2]" test="@wibble">
    <svrl:text>3</svrl:text>
  </successful-report>
</svrl:schematron-output>

Note

	Note
This result is obtained only if the implementation is invoked using `#ANY` to specify that the phase should be dynamically selected by evaluating `when` attributes. If no phase is selected with this schema, the behaviour matches that of specifying `#ALL` instead: all patterns become active and all are therefore evaluated.

This result is obtained only if the implementation is invoked using #ANY to specify that the phase should be dynamically selected by evaluating when attributes.

If no phase is selected with this schema, the behaviour matches that of specifying #ALL instead: all patterns become active and all are therefore evaluated.

Commentary

The introduction of this attribute entails the new string #ANY to specify that when should be used to determine the active phase.

Like #ALL and #DEFAULT, #ANY is not to be used as a phase name in a schema, but instead to invoke or configure validation, for example when passed as a parameter to an implementation at the command line.

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