This post introduces Optique, a new library created to address the pervasive problem of repetitive and often messy validation code in CLI tools. The author was motivated by the observation that nearly every CLI tool reinvents the wheel with similar validation patterns for dependent options, mutually exclusive options, and environment-specific requirements. Optique leverages parser combinators and TypeScript's type inference to ensure that CLI arguments are parsed directly into valid configurations, eliminating the need for manual validation. By describing the desired CLI configuration with Optique, TypeScript automatically infers the types and constraints, catching potential bugs at compile time. The author shares their experience of deleting large chunks of validation code and simplifying refactoring tasks. Optique aims to provide a more robust and maintainable approach to CLI argument parsing, potentially saving developers from writing the same validation logic repeatedly.
  • Asetru@feddit.org
    22·
    7 days ago

    The or() combinator means exactly one succeeds.

    Using “or” to define a function that does “xor”… Did that guy never hear about formal logic? That’s, like, first or second semester stuff…

    Here’s the thing: I don’t have a CS degree.

    sigh

    • Glitchvid@lemmy.worldEnglish
      2·
      6 days ago

      It’s an understandable interpretation for the lexical use of or which can imply exclusive disjunction.

      In Rust the result type has the method .or() which returns either Ok(A) or Ok(B) (but not both), and I don’t see clambering to change it to xor, because the exclusive nature is implicit both linguistically and in the type state.

      • Asetru@feddit.org
        1·
        5 days ago

        The result type in rust does not return a true/false but a type. More importantly though, it doesn’t return err if both values are set but simply returns the first value:

        So… It’s not only not mapping your input to truth values, it also behaves more like I’d expect an “or” to behave, which is not “xor” or, if there’s more than two inputs, “exactly one”, but succeeding if any input is set.

        • Glitchvid@lemmy.worldEnglish
          1·
          4 days ago

          …Which is basically how the OP’s or function also works, it takes several Option<T>s and returns the first valid one (and only that one), it doesn’t operate on boolean logic types — it’s a valid lexical use of or.

          • Asetru@feddit.org
            1·
            4 days ago

            Absolutely not.

            Mutually exclusive options

            Another classic. Pick one output format: JSON, YAML, or XML. But definitely not two.

            Emphasis mine.

            It takes the input and fails if there is more than one valid one, which decidedly isn’t what’s an “or” in comp sci.