About FLAP

FLAP (Fortran command Line Arguments Parser for poor people) is a pure Fortran 2003+ library for building powerful, user-friendly Command Line Interfaces (CLIs). It is inspired by Python's argparse module and follows the same philosophy: define your arguments once, and FLAP handles parsing, help generation, error reporting, and more.

Fortran programs often need rich command-line interfaces — optional switches, required parameters, boolean flags, positional arguments, mutually exclusive groups, and nested subcommands. FLAP provides all of this with a clean, consistent API and zero external dependencies beyond the Fortran standard library.

Authors

• Stefano Zaghi — @szaghi

Contributions are welcome — see the Contributing page.

Copyrights

FLAP is distributed under a multi-licensing system:

Use case	License
FOSS projects	GPL v3
Closed source / commercial	BSD 2-Clause
Closed source / commercial	BSD 3-Clause
Closed source / commercial	MIT