Specifying alternatives

A frequently occurring situation is when two macros exist but only one macro may contain valid values at a time. The user must decide which macro contains the valid values. The macro of type composite provide the groupComponents and selectedMacro properties. The first property contains the names of the component macros which belong to this group (this means only one contains valid values) and the latter (selectedMacro) contains the default value (which component is valid when the components first display). Besides components belonging to a group, a composite macro may contain components that are valid at all times. Slightly modifying the third example shows the following:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE template SYSTEM "resources/ruleTemplate.dtd" >
<template name="ex4">
<screen number="10">
    <editor macro="aggregate">
        <editor macro="text" label="Text">
            <parameter name="columns" value="30"/>
            <label-constraints fill="HORIZONTAL" insets="2,2,2,2"
                weightx="1" gridx="0" gridy="0"/>
            <constraints fill="NONE" insets="2,2,2,2" weightx="2"
                gridx="1" gridy="0" anchor="WEST"/>
        </editor>
    <editor macro="list" label="List">
        <label-constraints fill="HORIZONTAL" insets="2,2,2,2" weightx="1"
            gridx="0" gridy="1"/>
        <constraints fill="NONE" insets="2,2,2,2" weightx="2" gridx="1"
            gridy="1" anchor="WEST"/>
        </editor>
    </editor>
</screen>
<macro name="aggregate" type="composite">
    <vector-property name="groupComponents">
        <vector-elem>text</vector-elem>
        <vector-elem>list</vector-elem>
    </vector-property>
    <property name="selectedMacro">text</property>

    <macro name="text" type="varname"/>
    <macro name="list" type="combo-box">
        <vector-property name="listLabels">
            <vector-elem>Option A</vector-elem>
            <vector-elem>Option B</vector-elem>
            <vector-elem>Option C</vector-elem>
        </vector-property>
        <vector-property name="listValues">
            <vector-elem>option_a</vector-elem>
            <vector-elem>option_b</vector-elem>
            <vector-elem>option_c</vector-elem>
        </vector-property>
        <property name="listSelectedValue">option_b</property>
    </macro>
</macro>
<text>
#if ($aggregate.selectedMacro == "text")
Value of text is $aggregate.getMacro("text").
#else
Value of list is $aggregate.getMacro("list").selectedValue.
#end
</text>
</template>