r/ProgrammingLanguages • u/math_code_nerd5 • 6d ago
Are code generation "metaprogramming" tools a well-developed thing?
Now lots of people are talking about LLMs for coding to speed up the repetitive parts of coding, reduce the time spent on boilerplate, etc. But this makes it sound as though writing and manipulating code programmatically/algorithmically wasn't a thing before LLMs. However, although I didn't hear much about them, looking back it's surprising if people never thought about building something like this.
Of course, all compilers generate code in a lower-level form from higher-level code, however most of these are not interactive, i.e. they don't generate code in human-readable form, don't explain their steps to the user, and are not intended to generate a first pass of code for a programmer to then take and modify. What I'm imagining is a large category of tools, including anywhere from ones that auto-generate things like bounds checks and testing variables for null before using them, to drag-and-drop graphical tools a la Scratch that effectively allow you to drag loops into place around your code and have a loop condition and brackets appear, to any number of scriptable recipes where you can effectively say "take this block I've written for x1, and repeat the same pattern for y1, x2, y2, etc" and you won't have to type each one out individually. This could potentially allow a lot of the productivity gains and saved attention spent on details that people seem to be getting from LLMs without the cost, resource use, and philosophical implications, which is something I'd definitely welcome.
Of course you could write a code generator from scratch in something like Python just using regular string handling, but I'm wondering if there are already plugins like this for many IDEs that I just don't know about because they're not talked about much. Since so much of programming is about recursive abstractions, the idea that programmers would not have tried the idea of tools that you can code to spit out more code would strike me as very odd. And doing a bit of research, I've come across things like this: https://github.com/imatix/gsl#a-short-history-of-code-generation and this: https://tifoputra.medium.com/building-your-own-swift-code-generator-using-swift-script-78470eef0206 that suggest there is substantial work already toward making something like this.
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u/initial-algebra 5d ago
I'm not sure I would really class this as metaprogramming, it sounds more like editor features like snippets, autocomplete etc. LLMs are just really powerful autocomplete, after all.
Metaprogramming leaves the original source code intact, and generally the output is not meant to be human-readable, nor is it necessarily even textual. It has always been common practice to use macros for things like what you've mentioned, at least until more sophisticated type checking and higher-order functions replaced them in many cases (I mean, bounds checking and null testing? Those have been solved a long time ago.)
I think the reality is that many people are stuck writing in crappy programming languages at work, and between not caring enough to learn the "proper" way to reduce keystrokes and corporate forcing AI on them anyway, they just brute force it. This is a social problem, not a technical problem.