Fable.Python: F# Advent 2025

Write F#, run Python - a practical guide to Fable.Python

This is a comprehensive guide to Fable.Python, written as literate F# that transpiles to Python and generates its own documentation.

1. Introduction - What is Fable.Python and why use it
2. Getting Started - Setup, your first project, hello world
3. Bindings - Python interop and type bindings
4. Compatibility - Supported F# features and limitations

This guide is self-documenting: each chapter is an .fs file with embedded Markdown comments using FSharp.Formatting conventions. Fabletext, a literate converter inspired by jupytext (also written in F# and transpiled via Fable.Python), processes these files to generate the final Markdown output.

# Install dependencies
just setup
just restore
npm install

# Build everything (F# → Python → Markdown)
just all

# Or generate just the blogpost
just blogpost

just setup      # Install Fable and Python dependencies (uv)
just restore    # Restore NuGet packages
just build      # Compile F# to Python with Fable
just generate   # Convert chapters to individual markdown files
just blogpost   # Generate concatenated blogpost.md for publishing
just format     # Format Python files with ruff
just lint       # Lint Python (ruff) and Markdown (markdownlint)
just all        # Full pipeline: restore, build, generate, format, lint
just clean      # Remove generated files

chapters/
├── 01-introduction.fs      # What is Fable.Python
├── 02-getting-started.fs   # Setup and first project
├── 03-bindings.fs          # Python interop
└── 04-compatibility.fs     # F# feature support
tools/
├── fabletext.fs            # Fabletext converter (F#)
└── fabletext.fsproj
output/
├── chapters/               # Generated Python from chapters
└── tools/
    └── fabletext.py        # Generated converter (Python)
docs/
├── 01-introduction.md      # Individual chapter docs
├── ...
└── blogpost.md             # Concatenated for Hashnode

• Fable 5 (alpha) - F# to Python compiler
• uv - Python dependency management
• just - Command runner
• ruff - Python formatter/linter
• markdownlint - Markdown linter

GitHub Actions automatically:

• Builds all F# to Python
• Generates the blogpost
• Opens a PR when content changes

• Fable
• Fable.Python Documentation
• Fable.Python GitHub

Part of F# Advent 2025