Feature request: abs() function in ${.} expressions

[Michael Behrens]

While implementing some too complicated calculations in xacro I noticed that python's abs is not usable in xacro.
Sorry if it is available, but I could not find it in the python nor in the math namespace, and I could not find it in any documentation.

[Robert Haschke]

I can reproduce the missing abs function. However, I don't understand why it is missing. Here is a simple alternative: Use fabs:

<bar function="${fabs(-3)}"/>

[Michael Behrens]

Thank you! That would fix it.
I created a pull request to add support for abs. If you want to merge it, do so, otherwise just close it.

[Robert Haschke]

Fixed via d9b6679