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Ask HN: COBOL devs, how are AI coding affecting your work?

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Re: Ask HN: COBOL devs, how are AI coding affecting your work?

#31

Post by krupan »

Wuiserous wrote: post #17

I see it as a complete opposite for sure, I will tell you why. it could have been a threat if it was something you cannot control, but you can control it, you can learn to control it, and controlling it in the right direction would enable anyone to actually secure your position or even advance it. And, about the COBOL, well i dont know what the heck this is.

This is amazing! Thank you for confirming what I've been suspecting for a while now. People that actually know very little about software development now believe they don't need to know anything about it, and they are commenting very confidently here on hn.

Re: Ask HN: COBOL devs, how are AI coding affecting your work?

#32

Post by orwin »

antonymoose wrote: post #25
deaddodo wrote: post #22

Earlier quoted context omitted.

AI isn’t particularly great with C, Zig, or Rust either in my experience. It can certainly help with snippets of code and elucidate complex bitwise mathematics, and I’ll use it for those tedious tasks. And it’s a great research assistant, helping with referencing documentation. However, it’s gotten things wrong enough times that I’ve just lost trust in its ability to give me code I can’t review and confirm at a glanc…

I’m being pushed to use it more and more at work and it’s just not that great. I have paid access to Copilot with ChatGPT and Claude for context. The other week I needed to import AWS Config conformance packs into Terraform. Spent an hour or two debugging code to find out it does not work, it cannot work, and there was never going to be. Of course it insisted it was right, then sent me down an IAM Policy rabbit hole,…

Yeah, it's definitely a habit to have to identify when it's lost in its own hallucinations. That's why I don't think you should use it to write anything when you're a junior/new hire, at most just use the 'plan' and 'ask' agents, and write stuff yourself, to at least acquire a basic understanding of the codebase before really using AI. Basically if you're a .5x dev (which honestly, most of us are on a new environment), it'll make you a .25x, and make you stay there longer.

Re: Ask HN: COBOL devs, how are AI coding affecting your work?

#33

Post by thevinter »

Not a COBOL dev, but I work on migrating projects from COBOL mainframes to Java.

Generally speaking any kind of AI is relatively hit or miss. We have a statically generated knowledge base of the migrated sourcecode that can be used as context for LLMs to work with, but even that is often not enough to do anything meaningful.

At times Opus 4.5 is able to debug small errors in COBOL modules given a stacktrace and enough hand-holding. Other models are decent at explaining semi-obscure COBOL patterns or at guessing what a module could be doing just given the name and location -- but more often than not they end up just being confidently wrong.

I think the best use-case we have so far is business rule extraction - aka understanding what a module is trying to achieve without getting too much into details.

The TLDR, at least in our case, is that without any supporting RAGs/finetuning/etc all kind of AI works "just ok" and isn't such a big deal (yet)

Re: Ask HN: COBOL devs, how are AI coding affecting your work?

#34

Post by pjmlp »

krupan wrote: post #28
pjmlp wrote: post #16

I would assert this is affecting all programming languages, this is like the transition from Assembly to high level languages. Who thinks otherwise, even if LLMs are still a bit dumb today, is fooling themselves.

Compiling high level languages to assembly is a deterministic procedure. You write a program using a small well defined language (relative to natural language every programming language is tiny and extremely well defined). The same input to the same compiler will get you the same output every time. LLMs are nothing like a compiler.

If we ignore optimizing compilers and UB.

"Project the need 30 years out and imagine what might be possible in the context of the exponential curves"

-- Alan Kay

Re: Ask HN: COBOL devs, how are AI coding affecting your work?

#35

Post by eps »

egorfine wrote: post #24
0xCE0 wrote: post #13

I really wouldn't want any vibe-coded COBOL in my bank db/app logic...

vibecoding != AI. For example: I'm a senior dev, I use AI extensively but I fully understand and vet every single line of code I push. No exceptions. Not even in tests.

Aye. AI is also great for learning specifics of poorly documented APIs, e.g. COM-based brainrot from Microsoft.

Re: Ask HN: COBOL devs, how are AI coding affecting your work?

#36

Post by tjr »

egorfine wrote: post #24
0xCE0 wrote: post #13

I really wouldn't want any vibe-coded COBOL in my bank db/app logic...

vibecoding != AI. For example: I'm a senior dev, I use AI extensively but I fully understand and vet every single line of code I push. No exceptions. Not even in tests.

That is my preferred way to use it also, though I see many folks seemingly pushing for pure vibe coding, apparently striving for maximum throughput as a high-priority goal. Which goal would be hindered by careful review of the output.

It's unclear to me why most software projects would need to grow by tens (or hundreds) of thousands of lines of code each day, but I guess that's a thing?

Re: Ask HN: COBOL devs, how are AI coding affecting your work?

#37

Post by refneb »

eps wrote: post #35
egorfine wrote: post #24

Earlier quoted context omitted.

vibecoding != AI. For example: I'm a senior dev, I use AI extensively but I fully understand and vet every single line of code I push. No exceptions. Not even in tests.

Aye. AI is also great for learning specifics of poorly documented APIs, e.g. COM-based brainrot from Microsoft.

Hey now, that COM based rot paid for my house and kid’s college expenses.

Re: Ask HN: COBOL devs, how are AI coding affecting your work?

#38

Post by eps »

sarchertech wrote: post #21
jebarker wrote: post #18

Earlier quoted context omitted.

No, it doesn't. For example, you could use an AI agent just to aid you in code search and understanding or for filling out well specified functions which you then do QA on.

You 100% can use it this way. But it takes a lot of discipline to keep the slop out of the code base. The same way it took discipline to keep human slop out. There has always been a class of devs who throw things at the wall and see what sticks. They copy paste from other parts of the application, or from stack overflow. They write half assed tests or no tests at all and they try their best to push it thought the rev…

> But it takes a lot of discipline to keep the slop out of the code base.

It is largely a question of working ethics, rather than a matter of discipline per se.

Re: Ask HN: COBOL devs, how are AI coding affecting your work?

#39

Post by mkw5053 »

If I were using something like Claude Code to build a COBOL project, I'd structure the scaffolding to break problems into two phases: first, reason through the design from a purely theoretical perspective, weighing implementation tradeoffs; second, reference COBOL documentation and discuss how to make the solution as idiomatic as possible.

Disclaimer: I've never written a single line of COBOL. That said, I'm a programming language enthusiast who has shipped production code in FORTRAN, C, C++, Java, Scala, Clojure, JavaScript, TypeScript, Python, and probably others I'm forgetting.

Re: Ask HN: COBOL devs, how are AI coding affecting your work?

#40

Post by drrotmos »

deaddodo wrote: post #22
OGWhales wrote: post #12

I've not found it that great at programming in cobol, at least in comparison to its ability with other languages it seems to be noticeably worse, though we aren't using any models that were specifically trained on cobol. It is still useful for doing simple and tedious tasks, for example constructing a file layout based on info I fed it can be a time saver, otherwise I feel it's pretty limited by the necessary system…

AI isn’t particularly great with C, Zig, or Rust either in my experience. It can certainly help with snippets of code and elucidate complex bitwise mathematics, and I’ll use it for those tedious tasks. And it’s a great research assistant, helping with referencing documentation. However, it’s gotten things wrong enough times that I’ve just lost trust in its ability to give me code I can’t review and confirm at a glanc…

In my experience AI and Rust is a mixed bag. The strong compile-time checks mean an agent can verify its work to a much larger extent than many other languages, but the understanding of lifetimes is somewhat weak (although better in Opus 4.5 than earlier models!), and the ecosystem moves fast and fairly often makes breaking changes, meaning that a lot of the training data is obsolete.
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