<b>Tag:</b> macrodef

<span class="tagdoc" id="ivysettings.macrodef">Defines a new dependency resolver type based upon another.</span> This definition is very similar to the macrodef feature of ant for defining macro tasks. <span class="since">since 1.3</span>

This task eases the process of creating a new dependency resolver, because it avoids writing java code.

It is generally used in combination with the [[settings/include]] feature to help reuse a macro in multiple settings files.

A macro is defined by declaring an existing resolver within it. Then you can use attributes to pass parameters to the newly defined resolver type. Attributes are defined with a name, and optionally a default value, and are used using the following syntax: 
<code>@{attributename}</code>
<h2>Resolvers names</h2>
Since you can use the same macro several times it can define several resolvers (in a chain for instance), the resolver names need to be chosen carefully to avoid name conflicts (each resolver must have a unique name).

Here is how Ivy deals with the names of the resolvers defined in a macro:
<ul>
<li>if there is no name attribute on a resolver in the macrodef, then Ivy will use the name given when using the macro. This is what usually should be done for the main resolver defined in the macro</li>
<li>if there is a name attribute on a resolver in the macrodef, but this name doesn't contain a @{name} inside, then Ivy will use the provided name prefixed with the name of the macro separated by a dash</li>
<li>if there is a name attribute on a resolver in the macrodef, and this name contains @{name} somewhere, then Ivy will use this name, and replace @{name} with the name provided when using the macro.</li>
</ul>

Example:
<code type="xml">
<ivysettings>
  <macrodef name="mymacro">
    <chain>
      <ibiblio name="ex1" />
      <ibiblio name="ex2.@{name}" m2compatible="true" />
    </chain>
  </macrodef>
	
  <resolvers>
    <mymacro name="default" />
    <mymacro name="other" />
   </resolvers>
</ivysettings>
</code>
This is equivalent to:
<code type="xml">
<ivysettings>
  <resolvers>
    <chain name="default">
      <ibiblio name="default-ex1" />
      <ibiblio name="ex2.default" m2compatible="true" />
    </chain>
    <chain name="other">
      <ibiblio name="other-ex1" />
      <ibiblio name="ex2.other" m2compatible="true" />
    </chain>
   </resolvers>
</ivysettings>
</code>

<h1>Attributes</h1>
<table class="ivy-attributes">
<thead>
    <tr><th class="ivy-att">Attribute</th><th class="ivy-att-desc">Description</th><th class="ivy-att-req">Required</th></tr>
</thead>
<tbody>
    <tr><td>name</td><td>name of the resover type created</td>
        <td>Yes</td></tr>
</tbody>
</table>
<h1>Child elements</h1>
<table class="ivy-children">
<thead>
    <tr><th class="ivy-chld">Element</th><th class="ivy-chld-desc">Description</th><th class="ivy-chld-card">Cardinality</th></tr>
</thead>
<tbody>
    <tr><td>[[settings/macrodef/attribute]]</td><td>defines an attribute for the macro resolver</td>
        <td>0..n</td></tr>
    <tr><td>any resolver</td><td>defines the base resolver upon which this macro is defined</td>
        <td>1</td></tr>
</tbody>
</table>
<h1>Examples</h1>
Defining a simple macro:
<code type="xml">
  <macrodef name="mymacro">
    <attribute name="mymainrep"/>
      <filesystem name="fs1">
        <ivy pattern="@{mymainrep}/[organisation]/[module]/[type]s/[artifact]-[revision].[ext]"/>
        <artifact pattern="@{mymainrep}/[organisation]/[module]/[type]s/[artifact]-[revision].[ext]"/>
      </filesystem>
  </macrodef>
</code>
Using it:
<code type="xml">
  <resolvers>
    <mymacro name="default" mymainrep="path/to/myrep"/>
  </resolvers>
</code>
<hr/>
A complete example:
<code type="xml">
<ivysettings>
  <macrodef name="mymacro">
    <attribute name="mymainrep"/>
    <attribute name="mysecondrep"/>
    <attribute name="myseconddirlayout" default="[organisation]/[module]/[type]s"/>
    <chain>
      <filesystem name="fs1">
        <ivy pattern="@{mymainrep}/[organisation]/[module]/[type]s/[artifact]-[revision].[ext]"/>
        <artifact pattern="@{mymainrep}/[organisation]/[module]/[type]s/[artifact]-[revision].[ext]"/>
      </filesystem>
      <filesystem name="fs2" latest="latest-time">
        <ivy pattern="@{mysecondrep}/@{myseconddirlayout}/ivy-[revision].xml"/>
        <artifact pattern="@{mysecondrep}/@{myseconddirlayout}/[artifact]-[revision].[ext]"/>
      </filesystem>
    </chain>
  </macrodef>
	
  <resolvers>
    <mymacro name="default" mymainrep="path/to/myrep" mysecondrep="path/to/secondrep"/>
    <mymacro name="other" 
       mymainrep="path/to/myrep" 
       mysecondrep="path/to/secondrep" 
       myseconddirlayout="[module]/[type]s"/>
   </resolvers>
</ivysettings>
</code>