fypp
Python powered Fortran preprocessor
Decision gist · record as of 2026-08-14
Yes. Fypp is actively maintained, has no runtime dependencies, installs easily, carries a permissive BSD license, and solves a real problem for Fortran developers needing template metaprogramming and conditional compilation. It is production-stable and suitable for integration into scientific computing and numerical library build pipelines.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.5 or above; designed for Fortran development workflows.
- Low install friction with no runtime dependencies.
- Actively maintained as of 2026-03-03 with stable production status.
License · maintenance · safety
BSD (permissive) — BSD permissive license allows commercial and private use with minimal restrictions; suitable for most projects.
last release 2023-08-22 (1088 days) · last repo commit 2026-03-03 · 218 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 97,160 downloads/mo, #13,165 on PyPI
Alternatives
Verify before relying
pip install fypp
fypp source.fpp source.f90
# Or import the module in Python:
from fypp import fypp
fypp.main()- Whether the package works with Python versions beyond 3.9 (classifiers list up to 3.9 only).
- Current test coverage and CI/CD status to assess stability beyond the active maintenance signal.
What it is and what it does
Fypp is a command-line preprocessor and Python module that extends Fortran with metaprogramming capabilities by interpreting Python expressions embedded in preprocessor directives. It reads Fortran source files annotated with special directives (like #:if, #:for, #:def), evaluates Python logic to conditionally include code or generate templates, and outputs the processed Fortran. The tool integrates into build toolchains as a preprocessing step before compilation.
Instead of inventing its own expression syntax, Fypp leverages Python's full expression language for metaprogramming tasks—defining variables, writing macros, iterating over types to generate overloaded procedures, and inserting dynamic content like timestamps. It handles multiline strings, file inclusion, line numbering directives for debugging, and automatic line folding, making it suitable for large Fortran projects that need code reuse and conditional compilation without leaving the Fortran ecosystem.
Use it for
- Generate type-specific Fortran procedure overloads (e.g., real, complex variants) from a single template definition.
- Conditionally include MPI, OpenMP, or serial code paths based on preprocessor variables set at build time.
- Insert build metadata (timestamps, version strings) or debug assertions into Fortran source during preprocessing.
- Define reusable Fortran macros for common patterns (error checking, array bounds validation) to reduce code duplication.
- Automate boilerplate Fortran code generation for numerical libraries with multiple precision or dimension variants.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
Fypp is actively maintained, has no runtime dependencies, installs easily, carries a permissive BSD license, and solves a real problem for Fortran developers needing template metaprogramming and conditional compilation. It is production-stable and suitable for integration into scientific computing and numerical library build pipelines.
Install
fypp on PyPI
Before you install
Low install friction with no runtime dependencies. Actively maintained as of 2026-03-03 with stable production status.
Requires Python 3.5 or above; designed for Fortran development workflows.
License in practice
BSD permissive license allows commercial and private use with minimal restrictions; suitable for most projects.
Quickstart
pip install fypp
fypp source.fpp source.f90
# Or import the module in Python:
from fypp import fypp
fypp.main()Verify before relying
- Whether the package works with Python versions beyond 3.9 (classifiers list up to 3.9 only).
- Current test coverage and CI/CD status to assess stability beyond the active maintenance signal.
Package facts
| License | BSD permissive |
| Python support | Not specified |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | None |
| Maintenance | Actively maintained 1,088 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 97,160 / month, #13,165 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersIntended Audience :: Science/ResearchLicense :: OSI Approved :: BSD LicenseProgramming Language :: Python :: 3Programming Language :: Python :: 3.5Programming Language :: Python :: 3.6Programming Language :: Python :: 3.7Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Topic :: Software Development :: Code GeneratorsTopic :: Software Development :: Pre-processors |
Evidence: fypp-3.2-py3-none-any.whl
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