Abstract Quick Fixes

The Schematron QuickFix language is a simple language, and has just four types of operations that can be performed (add, delete, replace, and string replace). Being a simple language, it is easy to learn and use, and also easy to implement by applications.

Sometimes the developers that create the quick fixes need to use other types of operations (such as wrap, unwrap, rename, or join). They expect to have these operations defined in the language. Defining more operations in the language will help them create the quick fixes more easy, but this means that the language will be more complicated to learn and harder to be implemented by applications. A solution to this problem is to define a library of generic quick fixes that can be used for other types of operations.

A library of quick fixes can be implemented using abstract quick fixes. An abstract quick fix can be defined as a quick fix that has abstract parameters defined at the beginning of an sqf:fix element.

Example 14. Schematron abstract quick fix that can be used to rename a generic element

<sqf:fix id="renameElement" role="replace">
    <sqf:param name="element" abstract="true"/>
    <sqf:param name="newName" abstract="true"/>
        <sqf:title>Rename '$element' element in '$newName'</sqf:title>

An abstract quick fix can be instantiated from an abstract pattern. The pattern must have all the parameters declared in the quick fix, and the quick fix must declare all the abstract parameters that are used. Abstract parameters cannot be used as normal XPath variables. The reference of the abstract parameter will be replaced by the value specified in the abstract pattern.

Example 15. Schematron abstract pattern that reference an abstract quick fix

<sch:pattern id="elementNotAllowed" abstract="true">
    <sch:rule context="$element">
        <sch:assert test="false()" sqf:fix="renameElement"> 
            Element '$element' not allowed, use '$newName' instead.

The abstract pattern can be instantiated by providing different values for the parameters. Therefore, you can quickly adapt to multiple variants of XML formats and provide rules and quick fixes that will allow the user to correct the problems.

Example 16. Schematron abstract pattern instantiation

<sch:pattern is-a="elementNotAllowed">
    <sch:param name="element" value="orderedlist"/>
    <sch:param name="newName" value="itemizedlist"/>

Another solution for providing other quick fix actions without using abstract patterns is to use the sqf:call-fix element.