"I agree with afoken that an uniform global handle_error doesn't solve the need to define an ad-hoc catch condition."

My response may (or may not) alter your view on that. If it's not suitable for your needs, that's fine: as I said, "Just throwing a few ideas around.".

On the try/catch in 5.34, I generally don't use or suggest experimental features; in fact, I normally only mention them when recommending not to use them. In this instance, you had said, "... new syntax ... experimentally implemented ..."; accordingly, I pointed out a core experimental feature (in the certain knowledge that you're smart enough to understand the pitfalls) — I actually don't know if what you're doing is purely academic or for a production system.