The Zen of Bondrewd

July 17, 2023 · Andrew Belyaev

In this post I will outline the core philosophy behind the Bondrewd language – why it exists, what it is meant to be, and, most importantly, what the design choices should be based on.

As a side note, in retrospect this has turned out more expansive than would’ve been appropriate for a Zen, but I guess I’ll keep the name as is.

  • Flexibility is key
    Bondrewd is meant to be a general-purpose language, and in my view, the most important property of one is flexibility. Whatever the user (the programmer) wishes to do, they should be able to, even if it’s considered bad. The programmer is the one taking responsibility, so they should ultimately get the final say.

    This is largely inspired by Python’s philosophy of having many restrictions only in the form of “gentlemen’s agreements”, rather than hard rules. Checked rules are still convenient every now and then, but they should be opt-in, not opt-out.

    There will be a few exceptions to this at the core of the language, because without any fixed rules, there would be no language at all. A more formal statement would be that the inflexible core part of the language will be kept to a minimum, and the rest will be implemented in the standard library in a first-class manner. Ideally, the core bits will also seem first-class from within the language.

    As for why – well, with sufficient flexibility, (mostly) anything else can be built on top by the user. The two notable exceptions are convenient and simple syntax and performance, which are the next two points.

  • Performance is important
    Runtime performance, specifically. If you’re not interested in performance, Python more than satisfies the previous point. However, flexibility alone not only cannot provide performance, but is somewhat at odds with it. Bondrewd’s solution is to provide the flexibility at compile time, yet result in a binary that is as fast as if it was written in C++ or Rust.

    Actually, if you dig a bit deeper, you’ll find Python libraries like Numba, which compile parts of Python code either ahead-of-time or just-in-time. However, there are some flaws with an approach like this. Generally speaking, the issue is that Python’s semantics are designed with interpreted execution in mind. Since Numba has to work with functions written in Python, the expressiveness of the to-be-compiled code is limited significantly. For almost the same reason, it cannot be used to compile the whole program into a standalone binary (without packaging the entire Python interpreter with it). Bondrewd, on the other hand, comes with deliberate support for compilation on various levels, so it should make for a much better user experience in this regard.

  • Syntax should provide what the library cannot
    For a general-purpose language, common tasks must have convenient and simple syntax. However, the language should not try to provide everything, as that would end up an unmanageable bloat. Instead, Bondrewd provides syntactic facilities for the most general tasks, and for the rest, the user is expected to tolerate the slight syntactic inconvenience of procedural macros.
  • The program is its compilation script
    This is a corollary of the previous points. The simplest way to provide the most flexibility at compile-time is to treat the program not as a declarative definition, but as imperative instruction for what the compiled binary should contain. For semi-arbitrary reasons, I have dubbed this approach Shukufuku. Theoretically, any interpreted language could implement this, but since Bondrewd is designed with it in mind, it provides specific syntax for runtime code literals (i.e. functions, and generally everything non-compile-time you would expect in a traditional program). This way, programs not utilizing compile-time metaprogramming don’t suffer from added syntactic clutter, like they otherwise would’ve if Shukufuku had been added as a library feature to an existent language. (That being said, the aforementioned Numba can be treated, to some extent, as a Python Shukufuku library).
  • Encouraged solutions should be the simplest ones
    Or, on the flip side, complexity should be used as a tool to deter programmers from discouraged actions. This is really an extension to the very first idea. Something being discouraged, or even outright bad, is not a good enough reason to forbid it. It is, however, a reason to avoid facilitating the discouraged approach. This way, the programmer is drawn to the “right” way, but is still free to choose any other if they know what they’re doing.
  • Maintain familiarity to programmers
    While a radical or novel approach is usually the core of a language’s identity, it also acts as a barrier to entry. Bondrewd already has a set of defining ideas, so it should try to avoid pointless deviations in other areas. In particular, this implies a syntax in large parts borrowed from other languages (mostly Rust, and in some cases Python, at least at the time of writing). I should, however, point out, that in cases where some syntax or semantics could be slightly adjusted for a sufficient increase in generality and composability, such changes should definitely be considered.
  • Don’t violate programmer expectations
    Unless they originate in bad habits, maybe. The idea here is that a simple and flexible language should be predictable by default thanks to high composability and regular internal structure following the same rules as user code. This property is very prominent in Python, which is one of my favorite aspects of that language. Really, this rule can be paraphrased as “avoid making exceptions”.
  • This is a stupid one, but Insert a few Made in Abyss references here and there
    Since I have already named the language after a character from the series, I feel compelled to include a few references to it as well. As of right now, you may have already noticed that the packages are referred to as “cartridges”, and I’m thinking of referring to the root-of-all-namespaces, to which all cartridges belong, as a “backpack”. Another cool idea has been suggested, but I won’t specify it here to avoid spoiling the series for those who haven’t watched it yet. (I highly recommend it, by the way!)
  • TODO?… – maybe there’s something crucial that I forgot to mention. If that turns out to be the case, I’ll add it here. This is also your chance to propose a core principle to the language while it’s still in its infancy.
  • The Zen of Python mostly applies too 😉