pyWebLP: In Python, Yet Another Literate Programming Tool

Literate programming is an attempt to reconcile the opposing needs of clear presentation to people with the technical issues of creating code that will work with our current set of tools.

Presentation to people requires extensive and sophisticated typesetting techniques. Further, the "narrative arc" of a presentation may not follow the source code as layed out for the compiler.

py-web-tool is a literate programming tool based on Knuth's Web to combine the actions of weaving a document with tangling source files. It is independent of any particular document markup or source language. Is uses a simple set of markup tags to define chunks of code and documentation.

The pyweb.w file is the source for the various pyweb module and script files. The various source code files are created by applying a tangle operation to the .w file. The final documentation is created by applying a weave operation to the .w file.

Installation

This requires Python 3.10.

python -m pip install py-web-lp

This will install the pyweb module and all of its dependencies.

Produce Documentation

The supplied documentation uses RST markup; it requires docutils.

python3 -m pip install docutils

python3 -m pyweb src/pyweb.w -o src
rst2html.py src/pyweb.rst src/pyweb.html

Authoring

The pyweb.html document describes the markup used to define code chunks and assemble those code chunks into a coherent document as well as working code. You'll create a .w file with documentation and code.

If you're a JEdit user, the jedit directory can be used to configure syntax highlighting that includes py-web-lp and RST.

Operation

After installation and authoring, you can then run py-web-lp with the following command

python3 -m pyweb src/pyweb.w -o src 

This will create the various output files from the source .w file.

• pyweb.rst is the final woven document. This can be run through docutils for publication.
• pyweb.py, tangle.py, weave.py are the tangled code files.

All of the files are produced from a single source.

Testing

The tests directory includes pyweb_test.w, which will create a complete test suite. You can create this with the following command

python3 -m pyweb tests/pyweb_test.w -o tests 

This weaves a tests/pyweb_test.rst file. This can be run through docutils for publication.

This tangles several test modules: test.py, test_tangler.py, test_weaver.py, test_loader.py, test_unit.py, and test_scripts.py.

Use pytest to run all the tests.

Here's a typical sequence, used during development:

python3 bootstrap/pyweb.py -xw src/pyweb.w -o src
python3 src/pyweb.py tests/pyweb_test.w -o tests
PYTHONPATH=${PWD}/src pytest
rst2html.py tests/pyweb_test.rst tests/pyweb_test.html
mypy --strict src

Note that a previous release, untouched, is saved in the project's bootstrap directory. This is not changed during development, since py-web-lp is written with py-web-lp.