I really wish lisps were more popular (or, really, popular again). Most people can't make it past the non-Algol syntax, which is silly IMO. But they do also demand more of the user than a typical language.
Their use of metaprogramming doesn't just allow you to extend the language, it really expects that of the programmer. Which means you have to assume the role of language designer to some extent. Learning how to do that definitely feels like a way to level up your skills. But it seems uncommon for people to want to do that.
I think people underestimate how pragmatic meta programming can be because there are some obvious downsides. Arguably one of things that made Rust so popular was its inclusion of procedural macros.
But beyond that the thing I don't understand about the modern hate towards macros is that they are simply very fun.
As someone who is "into" programming languages (and making toy implementations of them), I think some of the most important macros are along the lines of Rust/Haskells `derive/deriving` for quickly enabling serialization, printing etc. Using a language without such capability quickly becomes frustrating once you move to any kind of "real" task.
In any kind of real task, serialization is not the hard part.
If you can write a meta program for it, you can execute that in CI and spit out generated code and be done with it. This is a viable approach in any programming language that can print strings to files.
It’s not frustrating, but maybe it feels tacky. But then you shrug and move on to the real task at hand.
Ruby, Python, and Typescript use metaprogramming rather heavily. They lack the homoiconic property of lisps, but they can do both higher-order functions and monkey-patching.
Meta-heavy code usually offers a nice DSL, but is proportionally harder to drill down through.
> But it seems uncommon for people to want to do that.
It becomes more obvious once you start managing developers vs being a solo dev. everyone making their own designer means the language can morph into a completely insular creation with a learning curve that expands exponentially with every new hire. A little extra boilerplate is the cost of standardized idioms that work across both your codebase that your new hires are already familiar with from working in that language at other companies. its why go was created. personally I prefer rust and elixir as good middle grounds.
This is a common reaction/belief but usually from people who have not actually managed a team of Lisp devs.
Lisp devs are managed in the same way as any other: You have style guidelines, design review, code review, etc. Sometimes a new macro is good and vastly simplifies code. It's accepted as a PR and documented like anything else. Sometimes a new macro is bad, and it's promptly rejected by the team. It's a persistent myth that Lisp programmers are just going to design their own little languages everywhere in a shared code base and it'll be impossible to understand.
(Case in point: Look at open source Lisp code. There isn't even management or code review there! Yet the vast majority of Lisp code is actually just functions and classes, with the occasional macro to reduce boilerplate. In some circumstances, you have a library offering a macro, and it's actually well documented and easy to understand. See Iterate, SERIES, etc. for actual examples.)
Rust or Elixir or Java or whatever aren't at all immune to monstrosities created by astronomically complex or baroque abstractions, FactoryFactoryFactories, and so on. How do teams avoid those? Style guidelines, design review, code review, etc.
Three thoughts (in the context of Common Lisp specifically):
- Every day that passes, the gulf between Lisp's tooling and what a typical user expects grows wider. It needs to escape Emacs and SLIME to something that feels complete and polished.
- There needs to be a little bit of a culture shift around Lisp to actually write programs that do things. How many programs can you download via apt or brew that are written in Lisp? They're executables at the end of the day so nothing in principle stops this from happening, but there's just a thread of modern Lisp culture where it's more fun to play around in the REPL and write creative libraries than to ship. (There are notable exceptions of course.)
- I personally like the quirkiness of Common Lisp, but there are so many ways to write it (imperative, functional, etc.), so many ways to structure your programs (one package, package per file, package inferred system, etc.), and so many ways to offer APIs (plain old data and functions, generic function protocols, etc.) that it makes it a combination of confusing and intimidating. I think shifting toward something a little more structured and disciplined like Coalton, while still giving the escape hatches to all of Common Lisp, would help a lot of people "join in" on building new code or building upon existing code.
Agreed. I think Clojure strikes a pretty reasonable balance here. It's opinionated about the programming paradigm, scales back some of the pain that comes from reader macros, and solves some of the bootstrapping problems by compatibility with other JVM languages.
I love clojure but the points still stand, kind-of.
- There is Calva for VS Code but the community default is emacs and cider
- How many programs in apt or brew are written in clojure? I'd concede that the community is great and focused on productivity, but it's so niche that you don't see much work out there made in clojure, and there is also a vestigial lisp sentiment to prefer building your own library from scratch instead of contributing to a standard library, which spreads the efforts of a small community too much
- Third one you need to mutate it a little bit: clojure is opinionated instead of having "so many ways", but its opinions, while great, are foreign to most programmers
Their use of metaprogramming doesn't just allow you to extend the language, it really expects that of the programmer. Which means you have to assume the role of language designer to some extent. Learning how to do that definitely feels like a way to level up your skills. But it seems uncommon for people to want to do that.
But beyond that the thing I don't understand about the modern hate towards macros is that they are simply very fun.
If you can write a meta program for it, you can execute that in CI and spit out generated code and be done with it. This is a viable approach in any programming language that can print strings to files.
It’s not frustrating, but maybe it feels tacky. But then you shrug and move on to the real task at hand.
Meta-heavy code usually offers a nice DSL, but is proportionally harder to drill down through.
It becomes more obvious once you start managing developers vs being a solo dev. everyone making their own designer means the language can morph into a completely insular creation with a learning curve that expands exponentially with every new hire. A little extra boilerplate is the cost of standardized idioms that work across both your codebase that your new hires are already familiar with from working in that language at other companies. its why go was created. personally I prefer rust and elixir as good middle grounds.
Lisp devs are managed in the same way as any other: You have style guidelines, design review, code review, etc. Sometimes a new macro is good and vastly simplifies code. It's accepted as a PR and documented like anything else. Sometimes a new macro is bad, and it's promptly rejected by the team. It's a persistent myth that Lisp programmers are just going to design their own little languages everywhere in a shared code base and it'll be impossible to understand.
(Case in point: Look at open source Lisp code. There isn't even management or code review there! Yet the vast majority of Lisp code is actually just functions and classes, with the occasional macro to reduce boilerplate. In some circumstances, you have a library offering a macro, and it's actually well documented and easy to understand. See Iterate, SERIES, etc. for actual examples.)
Rust or Elixir or Java or whatever aren't at all immune to monstrosities created by astronomically complex or baroque abstractions, FactoryFactoryFactories, and so on. How do teams avoid those? Style guidelines, design review, code review, etc.
- Every day that passes, the gulf between Lisp's tooling and what a typical user expects grows wider. It needs to escape Emacs and SLIME to something that feels complete and polished.
- There needs to be a little bit of a culture shift around Lisp to actually write programs that do things. How many programs can you download via apt or brew that are written in Lisp? They're executables at the end of the day so nothing in principle stops this from happening, but there's just a thread of modern Lisp culture where it's more fun to play around in the REPL and write creative libraries than to ship. (There are notable exceptions of course.)
- I personally like the quirkiness of Common Lisp, but there are so many ways to write it (imperative, functional, etc.), so many ways to structure your programs (one package, package per file, package inferred system, etc.), and so many ways to offer APIs (plain old data and functions, generic function protocols, etc.) that it makes it a combination of confusing and intimidating. I think shifting toward something a little more structured and disciplined like Coalton, while still giving the escape hatches to all of Common Lisp, would help a lot of people "join in" on building new code or building upon existing code.