Comment by Galanwe
12 hours ago
This is so true, I have seen it happen with so many projects. It always starts with a cute declarative DSL, and inevitably imperative / flow control structures emerge, at which point you wonder why they didn't use a real programming language in the first place and save you the hassle or learning a half baked imperative DSL.
- Puppet
- CMake
- Terraform
- ...
All these started with pure declarative DSL then incrementally created a nightmarish imperative monstrosity.
- Visual Studio project files are XML files that are interpreted line by line, and can contain variables, branches, and loops. Hell on earth.
They are badly copied Ant build files.
Ant came first, then when Microsoft redid the VS project format, they created MSBuild.
As incredible as it may sound, Ant is still easier to deal with than MSBuild.
Ant did not include IF THEN ELSE, unless you added the contrib package.
If you understood the paradigm, you could write branches in Ant files simply using properties and guards on properties ("unless"). Using IF in Ant was basically admission of not having understood Ant.
This said, I used Ant for a very limited amount of time.
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The legacy version of MSBuild was really bad, but the modern MSBuild project files for .NET are actually quite concise and clean by default?
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Horrible. Would’ve been much nicer if they’d reached for Scheme.
You say that, but people in OCaml keep bemoaning the use of mostly declarative s-expressions in the Dune build system. Imagine the reaction if MSBuild used an actual Scheme.
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what's even worse that schema uses extremely generic types with attributes denoting actual type.
Makes reading it even harder, and any possible constraints due to type safety go out of the window, so we get worst of both worlds.
Wesnoth the game also has that via WML. Looks very ugly and obfuscated.
CMake was never declarative AFAIK?
CMake today is effectively an eso-lang / Turing tarpit with some “modern” declarative conventions that people try to push.
"Modern CMake" is more about scoping all properties to the targets that they belong to (including stuff like what you also need to link against if you link against target foo) than about language features. The CMake language hasn't changed much except correcting some early weirdness about "if" and the addition of generator expressions, which are fortunately not often needed.
What's the old adage? Software expands until it can send email?
> All these started with pure declarative DSL then incrementally created a nightmarish imperative monstrosity.
"Huh?" I asked myself when you mentioned that Terraform is now imperative somehow. Took a look at the website again, and seems to still be HCL, and still be declarative. Am I missing something? How exactly is Terraform today a "imperative monstrosity"?
Terraform has modules which are an elaborate method of doing function calls. HCL 2 has loops and conditionals. It is most definitely imperative.
This is not necessarily a problem except that they had to live in the original HCL v1 landscape which makes them awkward syntactically.
> Terraform has modules which are an elaborate method of doing function calls
... What? How is modules a function call? It's just a hierarchy, everything about/with modules is still declarative.
> HCL 2 has loops and conditionals. It is most definitely imperative.
So what? Just because there is loops and conditionals doesn't mean it's suddenly imperative.
How exactly you do loops in HCL? Last time I used it, you still used declarative configuration for that, and use `for_each` as an declared option, you don't "call for_each which returns config", all that happens inside of HCL/TF, because it is declarative.
Did something change like yesterday or are people even here on HN so ignorant about what declarative vs imperative actually means?
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I think cmake kind of needs conditional checks though.
People love to hate on Maven's XML but at least it's been mostly the same since 2006. There are conditionals in profile activation expressions but they are very limited by design. Declarative done right, IMO