2. A sequence of commands

DocBook has no ``bold tag'' but it is customary to use the emphasis element with attribute role equals to bold. The following macro automates this:

<command name="convertToBold">
  <macro repeatable="true" undoable="true" 
         label="Convert to Bold">
      <command name="convert" 
               parameter="[implicitElement] emphasis" />
      <command name="putAttribute" parameter="role bold" />

Using a sequence element:

  1. The macro converts anything convertible to an emphasis element (generally text selection, but not only text selection) to an emphasis element.

  2. If step #1 is successful, the macro adds attribute role with value bold to the newly created emphasis element.

Note that if the first step of a sequence cannot be executed (this is tested before attempting to actually execute the sequence construct), the whole sequence construct cannot be executed.

Step #2 works without an "[implicitElement]" parameter for command putAttribute because the newly created emphasis element has been automatically selected by the convert command of step #1.

This is often the case. A quick way to learn this is to first perform interactively what needs to be automated by the macro.