xacro

library2.1.1pypypi✓ verified 88d ago

Xacro is a macro language for XML, commonly used in ROS (Robot Operating System) to parameterize and modularize URDF robot descriptions. It allows you to create reusable XML macros, include other files, and use mathematical expressions. Current version is 2.1.1, compatible with Python >=3.8. Release cadence is tied to ROS distributions, generally stable.

devops

pip install xacro

github ↗homepage ↗

INSTALL

IMPORT

SIG · XACRO

xacro

devopspythonv2.1.1

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

process_file

✓ from xacro import process_file

✗ import xacro; xacro.process_file(...)

In version 2+, the main entry point is process_file, not top-level execution with xacro.main().

Processes an XML string with xacro macros and outputs the expanded XML.

from xacro import process_file from io import StringIO # Example URDF snippet with a macro xml_input = '''<?xml version="1.0"?> <robot name="test" xmlns:xacro="http://ros.org/wiki/xacro"> <xacro:macro name="box" params="name x y z"> <link name="${name}"> <visual> <geometry> <box size="${x} ${y} ${z}"/> </geometry> </visual> </link> </xacro:macro> <xacro:box name="base" x="0.5" y="0.5" z="0.2"/> </robot>''' doc = process_file(StringIO(xml_input), mapping={'dummy': None}) print(doc.toprettyxml())

Debug

Known issues

breakingIn version 2.0, the API changed from command-line-only to a proper Python module. The old 'xacro' script no longer works as a direct import.

fix

Use 'from xacro import process_file' and call it programmatically instead of importing xacro and calling 'xacro.main()'.

affects: <2.0 to >=2.0

deprecatedThe 'xacro:include' tag with 'filename' attribute is deprecated in favor of 'xacro:include' with 'file' attribute to avoid name clashes with Python's built-in.

fix

Use <xacro:include file="path/to/file.xacro"/> instead of <xacro:include filename="..."/>.

affects: >=2.0

gotchaXacro uses Python expressions in ${} blocks. If you have a literal string that looks like a variable (e.g., ${...}), it must be escaped or quoted, otherwise it will raise a NameError.

fix

Use ${{...}} to escape a literal ${} or use single quotes around the value: e.g., <property value="'${not_a_var}'" />.

affects: all

Errors

Common errors & fixes

ImportError: cannot import name 'main' from 'xacro'

In xacro 2+, there is no 'main' function; the API changed to process_file.

fix

Use 'from xacro import process_file' and call process_file on your file or stream.

Upgrade

Version history

2.1.1latest on PyPI · released Aug 28, 2025

Audit

Dependencies

No dependency data recorded yet.

Agent activity

24 hits · last 30 days

node

Resources

githubhttps://github.com/ros/xacro ↗

homepagehttps://github.com/ros/xacro ↗