Re: [Caml-list] What if exn was not an open type?

["Petter A. Urkedal" <paurkedal@gmail.com>]

On 5 November 2017 at 21:49, Gabriel Scherer <gabriel.scherer@gmail.com> wrote:
> We also have return-by-local-exceptions in Batteries (the BatReturn
> module), but reports from js_of_ocaml users (namely, Clément
> Pit-Claudel) is that this style gets translated to extremely slow
> Javascript code -- functions from Batteries using this style (string
> search functions in particular) were a performance bottleneck on the
> javascript backend. I fixed the issue by rewriting all uses of
> BatReturn in Batteries libraries themselves.
> Long-term, it would be better to have Javascript backends produce
> better code on this, but I think it is rather difficult -- it is easy
> to compile efficiently local exceptions that are raised in the same
> basic block, but with_return takes a callback so you have to both
> inline and specialize before you are within reach of the optimization.

Sounds like something a PPX rewriter could solve.  It could also avoid
the need to manually scope it, if we accept the module-level let as
the scope.