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FORMAL: Fortran FORD VitePress Markdown Documentation HTML generator

Project description

FORMAL

F(ortran) (f)O(rd) (vitep)R(ess) M(arkdown) (document)A(tion) (htm)L

Generate beautiful API documentation websites for Fortran projects. FORMAL bridges FORD (Fortran Documenter) and VitePress (Vue-powered static site generator) -- it parses your Fortran !< doc comments and produces a complete, searchable, themed documentation site.

Showcases

Projects using FORMAL for their API documentation:

  • BeFoR64 — Base64 encoding/decoding library for Fortran  |  GitHub
  • FACE — Fortran ANSI Colors and Escape sequences  |  GitHub
  • FLAP — Fortran command Line Arguments Parser for poor people  |  GitHub
  • PENF — Portability Environment for Fortran poor people  |  GitHub

Features

  • Parses Fortran sources using FORD's battle-tested parser
  • Generates clean Markdown that VitePress renders natively
  • One page per module with: type components, bound procedures, subroutine/function signatures, argument tables
  • Auto-generated sidebar grouped by source directory structure
  • LaTeX math support in doc comments (rendered by MathJax)
  • Fortran syntax highlighting in code blocks
  • Scaffolds a ready-to-use VitePress site in seconds
  • Works with any FORD-compatible Fortran project

See the Documentation Guide.

Author

Stefano Zaghi -- szaghi

License

MIT License

Installation

From PyPI (recommended)

pipx install formal-ford2vitepress

Or with pip:

pip install formal-ford2vitepress

From source

git clone https://github.com/szaghi/formal.git
cd formal
pipx install -e .

Requirements

  • Python >= 3.9
  • FORD >= 7.0 (installed automatically as dependency)
  • Node.js >= 18 (for VitePress, needed at docs build time only)

Quick start

New project -- scaffold everything

cd /path/to/your/fortran/project
formal init --name "MyProject" --author "Your Name"
cd docs && npm install
formal generate
npm run docs:dev    # opens http://localhost:5173

Existing project -- just generate API docs

# If you already have a FORD project file:
formal generate --project doc/main_page.md --output docs/api

# Or let FORMAL auto-detect:
formal generate

Usage

formal init

Scaffolds a VitePress documentation site and creates a FORD project file for your Fortran sources.

formal init [project_root] [options]
Option Default Description
project_root . Root of the Fortran project
--name NAME Directory name Project name
--src-dir DIR [DIR...] Auto-detect src/ Source directories
--exclude-dir DIR [DIR...] Auto-detect Directories to exclude
--docs-dir DIR docs Where to create VitePress site
--ford-file PATH doc/formal.md FORD project file location
--docmark MARK < FORD doc comment marker (< = !<)
--author NAME Author name
--no-math Disable LaTeX math support
--no-fortran-highlight Disable Fortran syntax aliases

What it creates (never overwrites existing files):

your-project/
├── doc/
│   └── formal.md              # FORD project file
└── docs/
    ├── index.md               # Landing page
    ├── package.json           # npm config with scripts
    └── .vitepress/
        └── config.mts         # VitePress config with API sidebar

formal generate

Parses Fortran sources and generates VitePress Markdown API documentation.

formal generate [options]
Option Default Description
--project FILE Auto-detect FORD project file path
--output DIR docs/api Output directory for generated files
--src-root PATH Auto-detect Root path to strip from source paths
--quiet Suppress progress output

What it generates:

docs/api/
├── index.md                   # Index page listing all modules
├── _sidebar.json              # Sidebar groups (imported by config.mts)
├── adam_grid_object.md        # One page per Fortran module
├── adam_field_object.md
└── ...

Auto-detection: if --project is not given, FORMAL looks for these files in order:

  1. doc/formal.md
  2. doc/vitepress.md
  3. doc/main_page.md

Writing Fortran doc comments

FORMAL reads FORD-style !< doc comments (configurable via docmark):

module physics_solver
!< Compressible Navier-Stokes solver.
!< Supports 1D, 2D, and 3D configurations.

real(R8P), parameter :: GAMMA = 1.4_R8P !< Ratio of specific heats.

type :: solver_config
   !< Solver configuration.
   integer(I4P) :: order = 5 !< WENO reconstruction order.
   real(R8P)    :: cfl = 0.8 !< CFL number.
   contains
      procedure :: init !< Initialize the solver.
endtype solver_config

contains

subroutine compute_flux(self, q, flux)
!< Compute numerical flux.
!<
!< Uses the Rusanov approximate Riemann solver:
!< $$ F_{i+1/2} = \frac{1}{2}(F_L + F_R) - \frac{\lambda}{2}(U_R - U_L) $$
class(solver_config), intent(in)  :: self    !< Solver config.
real(R8P),            intent(in)  :: q(:)    !< Conservative variables.
real(R8P),            intent(out) :: flux(:) !< Numerical flux.

What gets extracted:

  • Module-level comments become the module description
  • Variable comments (same-line !<) become table cell descriptions
  • Type comments become type section descriptions
  • Procedure comments become procedure section descriptions with full argument tables
  • LaTeX math ($...$, $$...$$, \(...\), \[...\]) renders via MathJax

Generated page structure

Each module page contains (when applicable):

# module_name
> Module description

**Source**: `src/lib/common/module_name.F90`

## Variables
| Name | Type | Attributes | Description |

## Derived Types
### type_name
#### Components
| Name | Type | Attributes | Description |
#### Type-Bound Procedures
| Name | Attributes | Description |

## Interfaces
### interface_name

## Subroutines
### subroutine_name
```fortran
subroutine name(arg1, arg2)

Arguments | Name | Type | Intent | Attributes | Description |

Functions

(same as subroutines, plus return type)


## Integrating with an existing VitePress site

If you already have a VitePress site, add FORMAL's API sidebar to your config:

```typescript
// docs/.vitepress/config.mts
import apiSidebar from '../api/_sidebar.json'

export default defineConfig({
  markdown: {
    math: true,  // if you want LaTeX support
  },
  themeConfig: {
    sidebar: {
      // ... your existing sidebars ...
      '/api/': [
        {
          text: 'API Reference',
          items: [
            { text: 'Overview', link: '/api/' },
          ],
        },
        ...apiSidebar,
      ],
    },
  },
})

Then generate and build:

formal generate --project doc/my_ford_file.md --output docs/api
cd docs && npm run docs:build

Customization

See the Documentation Guide for:

  • Adding hand-written pages alongside API docs
  • Customizing sidebar structure and grouping
  • Modifying the generated Markdown layout
  • Writing effective Fortran doc comments
  • LaTeX math and Fortran syntax highlighting
  • Deployment to GitHub Pages, Netlify, etc.

How it works

Fortran .F90 sources
    │
    │  FORD parser (load_settings + Project + correlate)
    │  extracts modules, types, procedures, doc_list
    ▼
FORD Project object model
    │
    │  FORMAL generator (format_module, format_type, ...)
    │  walks the object tree, generates Markdown
    ▼
docs/api/*.md + _sidebar.json
    │
    │  VitePress (npm run docs:build)
    ▼
Static HTML documentation site

Key insight: FORD's pipeline goes parse → correlate → markdown → HTML. FORMAL hooks in after correlate() and reads the raw doc_list (Markdown strings) from every entity, skipping FORD's own HTML generation entirely. VitePress handles the Markdown-to-HTML conversion with its own theme.

Development

Setup

git clone https://github.com/szaghi/formal.git
cd formal
pip install -e ".[dev]"

This installs FORMAL in editable mode along with pytest and ruff.

Running tests

# Run all tests (unit + integration)
pytest -v

# Run unit tests only (no FORD dependency needed)
pytest -v -m "not integration"

# Run integration tests only (requires FORD)
pytest -v -m "integration"

# Quick summary
pytest --tb=short

Test structure

tests/
├── mocks.py                     # Lightweight mock FORD objects for unit tests
├── conftest.py                  # Shared fixtures
├── fixtures/
│   └── sample_module.F90        # Fortran fixture for integration tests
├── test_formatting.py           # strip_html, escape_pipe, format_doc, inline_doc, ...
├── test_classify.py             # _classify_module sidebar grouping
├── test_entity_formatters.py    # format_variable_table, format_procedure, format_type, ...
├── test_scaffold.py             # create_ford_project_file, init_vitepress_site, ...
├── test_cli.py                  # CLI argument parsing and command dispatch
└── test_integration.py          # Full pipeline: Fortran fixture -> FORD parse -> Markdown

Unit tests use mock objects that mimic FORD entities by duck-typing, so they run without FORD parsing overhead. Integration tests exercise the full pipeline (FORD parse + Markdown generation) and are marked with @pytest.mark.integration.

Linting

ruff check src/ tests/
ruff format --check src/ tests/

Releasing a new version

A release script at scripts/build_publish.sh automates the full release pipeline.

One-command release

./scripts/build_publish.sh release 1.0.0

This runs through every step with a confirmation prompt upfront:

Step Action Aborts if...
Pre-flight Checks clean working tree, tag doesn't exist Uncommitted changes or tag collision
1. Bump Updates version in pyproject.toml and src/formal/__init__.py Invalid format or already at that version
2. Commit git commit -m "release: v1.0.0"
3. Build Clean build of sdist + wheel, validates with twine Build or validation failure
4. Test Installs wheel via pipx, checks --version and --help Version mismatch or broken CLI
5. Tag git tag -a v1.0.0 -m "Release v1.0.0"
6. Publish twine upload dist/* to PyPI Upload failure
7. Push Pushes commit and tag to origin

Individual steps

Each step is also available standalone for more control:

# Bump version without committing (useful for pre-release tweaks)
./scripts/build_publish.sh bump 0.2.0

# Build and validate only
./scripts/build_publish.sh build

# Smoke-test the built wheel
./scripts/build_publish.sh test

# Publish to TestPyPI first (dry run)
./scripts/build_publish.sh testpublish

# Publish to PyPI (assumes dist/ already built)
./scripts/build_publish.sh publish

# Build + publish in one go (no version bump)
./scripts/build_publish.sh all

Where the version lives

The version is stored in two files that the bump / release commands update together:

File Line Used by
pyproject.toml version = "X.Y.Z" PyPI, build tools
src/formal/__init__.py __version__ = "X.Y.Z" formal --version, runtime

Requirements for publishing

  • A PyPI account with an API token
  • build and twine available via pip or pipx (the script auto-detects both)

Acknowledgments

  • FORD by Chris MacMackin -- the Fortran parser that makes this possible
  • VitePress -- the static site generator

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