[melodic-only] name 'sorted' is not defined in macro argument.

[Michael Görner]

I ran into this trying to run https://github.com/captain-yoshi/scene_parser (as dependency of https://github.com/captain-yoshi/moveit_benchmark_suite) on melodic.

xacro 1.14.8 (noetic) supports this piece of code:

<?xml version="1.0" ?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro" name="test">
  <xacro:macro name="foo" params="sorted_keys:=^">
    <xacro:property name="xyz" value="${sorted_keys}"/>
  </xacro:macro>

  <xacro:foo sorted_keys="${sorted([2,1,0])}"/>
</robot>

1.13.12 (melodic) on the other hand fails with

name 'sorted' is not defined
when evaluating expression 'sorted([2,1,0])'

At first glance it looks like #278 should have fixed this and was released in 1.13.12.
Is the failure in melodic intended or is this an unresolved bug in the branch?

[Robert Haschke]

Actually, it is a bug in Noetic, that sorted() works! I'm looking into the issue.

[Captain Yoshi]

My use case for sorted is for looping a map which you can only loop as a list in Xacro (I think). I could change my map to a list but then I loose the ability to get the data by name. Maybe there are other ways to do it without using sorted.

apcshelf:
  subframes:
    binA:
      xyz: [0.10479, -0.291029, 1.52393]
    binB:
      xyz: [0.10479, 0, 1.52393]

[Robert Haschke]

Sorry, my statement was misleading: I plan to keep sorted both in Melodic and Noetic. However, the (current) availability of sorted in Noetic pointed me to another issue.
@captain-yoshi: Could elaborate more about your use? What do you mean by "looping a map"? I'm curious how you "unfold" the loop. Can you provide the xacro expression you are using?

[Michael Görner]

Can you provide the xacro expression you are using?

the full macro I based the minimal example on can be found here.

[Robert Haschke]

Fixed via 2a130a9.
Releases triggered into Melodic, Noetic, Foxy, Galactic, Rolling

[Robert Haschke]

The full macro I based the minimal example on can be found here.

That's so cool. I never thought about calling the macro recursively to unroll a loop!

@captain-yoshi, you can even simplify a little more. You are right, you can only loop over a list in this fashion. But you could easily pass the list (of map values) as items="${list(dict(a=1, b=2, c=3, d=4, e=5).values())}":

<robot name="loop" xmlns:xacro="http://www.ros.org/wiki/xacro">
	<xacro:macro name="loop" params="items:=^">
		<xacro:if value="${items}">
			<!-- pop first item from list -->
			<xacro:property name="item" value="${items.pop(0)}"/>

			<item>${item}</item>

			<!-- recursively call myself -->
			<xacro:loop/>
		</xacro:if>
	</xacro:macro>
	<xacro:loop items="${[1,2,3,4,5]}"/>
</robot>

[Michael Görner]

Thanks for the impressively fast debugging and sound bugfix+issue fix! 🥇

[Captain Yoshi]

Thank you very much Robert !!