Problem with xacro:if value="${model_type == A_model_type}"

edit

I can think of a couple of "clean" ways to do this.

I do not know which way is better. There should be other ways to achieve this as well. With Option-1, child_X.xacro can be very small, and is dependent on parent.xacro. In Option-2, each xacro file is not inter-dependent. wholerobot_model_X.xacro can be a little larger than Option-1 but still concise enough.

Option-1. Split xacro files into "parent/abstract" and "child/concrete" files.

parent.xacro:

:
<!-- Only load the specified model -->
<xacro:macro name="model_to_be_inserted" params="modelfile_path">
  <xacro:include filename="${modelfile_path}"/>
</xacro:macro>
:

child_a.xacro

:
<xacro:include filename="parent.xacro" />
:
<xacro:model_to_be_inserted modelfile_path="A_model_type" />
:

Option-2. Split your robot definition into smaller components as xacro files, then "assemble" them in another xacro for the specific design.

Say, split components of upper-body humanoid into {head, torso, left_arm, left_hand, right_arm, right_hand}.xacro, and you want to switch with customize hands.

wholerobot_model_A.xacro

:
<xacro:include filename="head.xacro"/>
<xacro:include filename="torso.xacro"/>
<xacro:include filename="left_arm.xacro"/>
<xacro:include filename="A_model_type_l.xacro"/>
<xacro:include filename="right_arm.xacro"/>
<xacro:include filename="A_model_type_r.xacro"/>
: