Valid8r, Functional validation for Python CLIs using Maybe monads
I built Valid8r because I got tired of writing the same input validation code for every CLI tool. You know the pattern: parse a string, check if it's valid, print an error if not, ask again. Repeat for every argument. The library uses Maybe monads (Success/Failure instead of exceptions) so you can chain parsers and validators: # Try it: pip install valid8r from valid8r.core import parsers, validators # Parse and validate in one pipeline result = ( parsers.parse_int(user_input) .bind(validators.minimum(1)) .bind(validators.maximum(65535)) ) match result: case Success(port): print(f"Using…
Valid8r, Functional validation for Python CLIs using Maybe monads launched on November 9, 2025 with 6 votes, #2,995 of 9,796 launches that month and more than 75% of that year's launches.
What it does
Contribute to mikelane/valid8r development by creating an account on GitHub.
In the maker’s words, at launch
I built Valid8r because I got tired of writing the same input validation code for every CLI tool. You know the pattern: parse a string, check if it's valid, print an error if not, ask again. Repeat for every argument. The library uses Maybe monads (Success/Failure instead of exceptions) so you can chain parsers…
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