API review

Proposer: Stu Glaser

Present at review:

• List reviewers

Question / concerns / comments

Enter your thoughts on the API and any questions / concerns you have here. Please sign your name. Anything you want to address in the API review should be marked down here before the start of the meeting.

• Bhaskara
  • The api is currently described by example. There should be an authoritative reference. Some specific questions I have:
    • What's the behavior for nested macroexpansion?
    • What happens when there are parameter name collisions (given nested macros)?
    • What are the command line arguments and return value of the xacro executable?
• John
  • unit tests
    • example error behavior

      • test2.xacro

        <?xml version="1.0"?>
        <robot>
        hey
        <abc>
        </abc>
        </robot>

      • test.xacro

        <?xml version="1.0"?>
        <robot name="pr2">
          <include filename="test2.xacro" />
        </robot>

      • rosrun xacro xacro.py test.xacro - parse successful, discards hey

        <?xml version="1.0" ?><robot name="pr2">
        
          <abc>
        </abc>
        
        </robot>

Meeting agenda

To be filled out by proposer based on comments gathered during API review period

• Escaping ${ as $${
• Make sure you can't define parameters with any of {}$

• undefined parameters should error out hard. #1176

• xacro: namespace or xacro_? Josh considers xacro: to be better. Depends on how well the python xml parser handles namespaces. xacro:macro sounds funny.
• It's difficult to tell what's getting replaced (particularly if you've never seen a xacro file before).
• Append _macro to all the macro names? Have xacro do it automatically?

• Add recursive variable substitution #1497. Consider postponing until after 1.0

<xacro:macro pr2_base_macro ...> ... <

OR

<xacro:macro name="pr2_base" ... /> <xacro:pr2_base ... /> (BEST)

OR

<xacro_macro name="pr2_base[_macro]" ... /> (maybe just by convention) <pr2_base_macro ... />

OR

<macro name="pr2_base_macro" ... /> (by convention) <pr2_base_macro ... /> (Also support xacro_macro and xacro_parameter if namespaces don't work)

and also support xacro:macro

And if they use namespaces once, continue to expect them.

Conclusion

Package status change mark change manifest)

• Action items that need to be taken.

• Major issues that need to be resolved