Why not place exn in function signature?

[bobbypriambodo]

There’s also a lively discussion here:

Specific reason for not embracing the use of exceptions for error propagation?

I don’t understand why one would not use exceptions to propagate errors in OCaml. The corresponding chapter in Real World OCaml has this quote: The right trade-off depends on your application. If you’re writing a rough-and-ready program where getting it done quickly is key and failure is not that expensive, then using exceptions extensively may be the way to go. If, on the other hand, you’re writing production software whose failure is costly, then you should probably lean in the direction of …