PyXindy (Python port of xindy)

Python reimplementation of xindy, the flexible index processor originally written in CLISP. PyXindy aims to be a drop-in replacement where the original xindy is difficult to install or integrate (for example with Tectonic or minimal TeX setups).

Background and history

• makeindex: introduced in 1987 by Pehong Chen, bundled with TeX distributions through the late 1980s and 1990s as the default indexer for LaTeX. It remains widely available in TeX Live and MiKTeX.
• xindy: created in the mid-1990s (first public releases in 1996) by Joachim Schrod to handle multilingual indexing, flexible sort rules, and markup targets beyond TeX (SGML/HTML). Version 2.x has shipped with TeX Live since the early 2000s.

Together they form a decades-old toolchain; PyXindy keeps the mature behavior while modernizing the implementation and packaging.

Why PyXindy port

1. Easier installation: pure-Python stack, no CLISP dependency, plays nicely with uv, pip, and containerized CI.
2. Better integration: Tectonic and other minimal TeX environments can use xindy-like features without installing a full TeX Live.
3. Maintainability: Python codebase lowers the barrier for contributors and makes testing/CI straightforward.
4. Extensibility: reuses the historical xindy modules/styles while making it simpler to experiment with new features or diagnostics.

Usage

lualatex document.tex
uv run xindy -M path/to/style.xdy -o document.ind document.raw
lualatex document.tex

Quick commands

• Generate an index from .raw with a .xdy style:

  uv run xindy-py -M path/to/style.xdy -o output.ind path/to/index.raw
  

• Convert a TeX .idx file to .raw:

  uv run texindy-py path/to/input.idx -o output.raw
  

• Use the makeindex-compatible interface:

  uv run makeindex-py path/to/input.idx -o output.ind -t output.ilg -c
  

Entry points

• xindy-py: core processor; reads .raw plus .xdy style and renders the formatted index.
• texindy-py: TeX converter; turns .idx into .raw suitable for xindy processing.
• makeindex-py: makeindex-compatible wrapper layered on the xindy engine; accepts common -c/-l/-o/-t flags.
• makeglossaries-py: glossaries helper; inspects LaTeX .aux to drive makeindex-py/xindy for glossary files.

Historical xindy modules/styles (vendor/xindy-2.1/modules) are resolved automatically via require. The wrapper makeindex-py supports the usual -l/-c/-o/-t flags.

xindy CLI

uv run xindy-py [-M style.xdy] [-o output.ind] [-L searchpath] [-C encoding] [-l logfile] [-t] input.raw

• -M/--module/--style: .xdy style to use (defaults to <raw>.xdy)
• -o/--output: output target (stdout if omitted)
• -L/--searchpath: extra search paths for require (merged with XINDY_SEARCHPATH)
• -C/--codepage: output encoding (default: utf-8)
• -l/--log: write a brief log file
• -t/--trace: show Python tracebacks on errors

tex2xindy

uv run texindy-py input.idx -o output.raw --input-encoding latin-1 --output-encoding utf-8

• Handles hierarchies !, display @, encap |, basic TeX macros/escapes, crossrefs see{target} → :xref.
• Emits :tkey when the displayed form differs from the sort key.

makeindex4

uv run makeindex-py input.idx -o output.ind -t output.ilg [-c] [-l]

• -c: compress spaces in keys (makeindex behavior)
• -l: ignore spaces for sorting (adds sort-rule " " "")
• --debug: print tracebacks; otherwise errors are summarized and written to the .ilg log
• Generates a temporary style, detects attributes/crossrefs, loads tex/makeidx4.xdy.

Examples

• Replay a historical fixture:

  uv run xindy-py -M vendor/xindy-2.1/tests/ex1.xdy \
        -o /tmp/ex1.ind vendor/xindy-2.1/tests/ex1.raw
  

• Chain .idx → .ind in one command:

  uv run makeindex-py vendor/xindy-2.1/tests/infII.idx -o /tmp/infII.ind
  

Development

1. Create a virtual environment and install dependencies:

   uv sync --extra dev  # or: pip install -e .[dev]
   

2. Run tests and linters:

   uv run pytest
   uv run ruff check
   

3. Smoke-test the binary:

   python -m xindy --version
   

The roadmap is tracked in PLAN.md.