ffmt 0.3.1

A fast, configurable Fortran formatter with Fypp, Doxygen, and OpenACC/OpenMP support
Documentation
# ffmt

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A fast, configurable Fortran formatter with support for Fypp, Doxygen, and OpenACC/OpenMP directives. Written in Rust. Installable via `pip`.

**[Documentation]https://ffmt-fortran.readthedocs.io** | **[Configuration]https://ffmt-fortran.readthedocs.io/en/latest/configuration/** | **[Changelog]https://github.com/sbryngelson/ffmt/releases**

## Installation

```bash
pip install ffmt
```

Or via Cargo:

```bash
cargo install ffmt
```

## Quick start

```bash
ffmt src/                        # format in-place
ffmt --check src/                # CI mode (exit 1 if changes needed)
ffmt --diff src/                 # show colored diff
ffmt -j 8 src/                   # parallel
cat file.fpp | ffmt -            # stdin/stdout
```

## Features

- **Code** -- indentation, whitespace normalization, keyword casing, named ends, line wrapping, operator modernization (`.eq.` -> `==`), double-colon enforcement, trailing semicolon removal
- **Comments** -- rewrapping, inline spacing (S102), `!<` alignment, `!&`/`& !` cleanup, format suppression (`! ffmt off/on`)
- **Structure** -- blank line management around openers/closers/`#ifdef`, declaration `::` alignment, declaration/use compaction
- **Preprocessor** -- Fypp (`#:if`, `$:`, `@:`), C preprocessor (`#ifdef`), OpenACC (`!$acc`), OpenMP (`!$omp`)
- **Opt-in** -- multi-statement splitting, assignment alignment, `&` column alignment, use-statement reformatting

Most options accept `true`, `false`, or `"preserve"`. See the [configuration reference](https://ffmt-fortran.readthedocs.io/en/latest/configuration/) for all options.

## Configuration

Create `ffmt.toml` or add `[tool.ffmt]` to `pyproject.toml`:

```toml
indent-width = 4
line-length = 132
keyword-case = "lower"
modernize-operators = true
enforce-double-colon = true

[whitespace]
relational = true
multdiv = false
```

## CI

```yaml
# GitHub Actions
- uses: sbryngelson/ffmt@latest
  with:
    args: "--check src/"
```

```yaml
# pre-commit
repos:
  - repo: https://github.com/sbryngelson/ffmt
    rev: v0.3.0
    hooks:
      - id: ffmt
```

## Other Fortran formatters

| Formatter | Language | Status | Notes |
|-----------|----------|--------|-------|
| [fprettify]https://github.com/fortran-lang/fprettify | Python | Unmaintained | Free-form only. Fypp support. |
| [findent]https://github.com/wvermin/findent | C | Active | Indentation and fixed/free conversion. |
| [Codee Formatter]https://www.codee.com | Proprietary | Active | Commercial. Tree-sitter based. |
| [LFortran fmt]https://lfortran.org | Rust | In development | AST-based. |
| [Fortitude]https://github.com/PlasmaFAIR/fortitude | Rust | Active | Linter with auto-fix. |

## License

MIT