pyMetric is code metric tool. Although it may be more micro library. And not without a reason.
By default comment metrics available only for python code. But it is really simple to add new language support. Just override filter and process methods in pymetric.extensions.BaseFileMetric And add it to Metric class.
There is no docs because code is few and it is commented well.
Example of working script can be found in metric.py. To start it on windows, click 'run.bat'
pyMetric is distributed under BSD licence.