depend¶

depend provides dependent-style typing for Python: runtime-validated, statically assisted, and built around structured predicates.

The library keeps the runtime honest and uses mypy as a useful but incomplete assistant. It is not a complete theorem prover, and it does not try to turn arbitrary Python into logic.

The documentation is built with MkDocs and published to GitHub Pages from this repository.

Quick start¶

from depend import GreaterThan, checked, refined, validate

PositiveInt = refined(int, lambda x: x > 0, name="PositiveInt")

@checked
def repeat(text: str, n: PositiveInt) -> str:
    return text * n

assert validate(3, PositiveInt) == 3
assert repeat("ha", 3) == "hahaha"

What to read next¶

• refinements.md for Predicate, where, and known predicates
• checked-functions.md for @checked, ensure, and return validation
• sized-collections.md for symbolic lengths
• numpy-shapes.md for array shapes and dtypes
• proofs.md for proof objects and proof requirements
• registries.md for registry metadata
• mypy-plugin.md for plugin setup
• limitations.md for the edges of the system