Preppy is ReportLab's templating system.  It was developed in late 2000 and has
been in continual production use since then.  It is open source (BSD-license).

The key features are:

- *small*.  Preppy is a single Python module.  If you want a templating system
  'in the box', it's easy to include it in your project
- *easy to learn*.  It takes about one minute to scan all the features
- *just Python*.  We have not invented another language, and if you want to do
  something - includes, quoting, filters - you just use Python
- *compiled to bytecode*: a .prep file gets compiled to a Python function in
  a .pyc file
- *easy to debug*: preppy generates proper Python exceptions, with the correct
  line numbers for the .prep file.  You can follow tracebacks from Python
  script to Preppy template and back, through multiple includes
- *easy to type and read*.  We've been using ``{{this}}`` syntax since well
  before Django was thought of
- *8-bit safe*:  it makes no assumption that you are generating markup and does
  nothing unexpected with whitespace; you could use it to generate images or
  binary files if you wanted to.

WWW: http://preppy.readthedocs.org/en/latest/