<switch> jump to matching case

name

switch

xml namespace

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Jump to a location with in a code block, based in an input value.

This tag takes a value (on) and jumps to a <case> in the enclosed block that has a matching value. If there is no matching <case>, then execution will move to the enclosed <default-case>. If no default case exists, the entire block is skipped.

This tag is useful in situations where a chain of <if> and <elif> tags would otherwise be used. Here's an example:

<switch on="species">
    <case>human</case>
    <echo>Humans come from Earth</echo>

    <case>hynerian</case>
    <echo>Hynerians come from Hyneria</echo>

    <default-case/>
    <echo>I have no idea where ${species}s come from</echo>
</switch>

The above code is equivalent to the following:

<if test="species=='human'">
    <echo>Humans come from Earth</echo>
</if>
<elif test="species=='hynerian'">
    <echo>Hynerians come from Hyneria</echo>
</elif>
<else>
    <echo>I have no idea where ${species}s come from</echo>
</else>

The <switch> version is generally clearer, especially with a large number of conditions.

If the on attribute is not given, then the case's if attribute is checked. Here's the previous example, implemented without the on attribute:

<switch>
    <case if="species=='human'"/>
    <echo>Humans come from Earth</echo>

    <case if="species=='hynerian'"/>
    <echo>Hynerians come from Hyneria</echo>

    <default-case/>
    <echo>I have no idea where ${species}s come from</echo>
</switch>