Re: [Haskell-cafe] Examples of Continuation monad that impossible to understand and maintain?

Based on the preceding paragraph, I think that by “abuse” it means overuse, as in using CPS when you could have used straightforward code. I can imagine someone doing at the source code level the sort of things that would be done by a CPS-based compiler (converting everything possible to CPS), and ending up with a mess. For example, imagine you started with this code snippet: let x = f a y = g x in h x y If you fully convert that to CPS you’d end up with 3 continuations (I think) and it would be much harder to understand. And adding an additional let binding later might involve a bunch of restructuring. I assume it just means that sort of thing. When someone first learns about continuations and their generality, it can be tempting to go overboard. Jeff

On Aug 31, 2021, at 3:03 AM, YueCompl via Haskell-Cafe wrote:

Dear Cafe,

I'm wrapping up my CPS codebase to provide some monadic interface, it appears almost the Cont monad, so the following statement is a pretty valid caveat to me now:

...

Abuse of the Continuation monad can produce code that is impossible to understand and maintain.

Which can be viewed in context of Hackage at: https://hackage.haskell.org/package/mtl/docs/Control-Monad-Cont.html#:~:text...

But I can't find concrete examples demonstrating the "impossible to understand and maintain" situation, in figuring out what pitfalls I'd rather to avoid.

Please share what you know about it, many appreciations!

Background of my CPS necessarity:

Library code need to delegate STM transaction boundary delimitation to (scripting) application code, though `inlineSTM :: STM a -> m a` can be used to force some action to be within current tx, the usual `>>=` binding should honor whether a separate `atomically` tx should be issued for its rhs computation, as specified by the scripting context.

Thanks, Compl

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