Finding a Filename Extension for Literate Sources

Finding an easy to remember, unused file name extension is not easy.

.py.txt

a double extension (similar to .tar.gz, say) seems most appropriate (at least on UNIX). The same scheme can be used for c.txt, p.txt and the like. However, it fails on FAT16 file systems.

.pytxt

is recognised as extension by os.path.splitext but also fails on FAT16

.pyt

(PYthon Text) is used by the Python test interpreter pytest

.pyl

was once mentioned as extension for “literate Python” files in an email exchange but subsequently used for Python libraries.

.lpy

seems to be free (as by a Google search, “lpy” is the name of a python code pretty printer but this should not pose a problem).

.tpy

seems to be free as well.

All these extensions are Python specific. A new search for nice and unused extensions would have to be repeated for every language supported by PyLit.

After considering the alternatives, the additional extension .txt was chosen for the text source (for Python this becomes py.txt).