Hi,
I was playing around with the new IO system a lot and got some very high level
feedback on that. Currently the IoResult objects implement a few traits to pass
through to the included success value and to dispatch method calls.
That's nice but it means that from looking at the code you can easily miss that
a result is involved and if you add methods you need to add manual proxy methods
on the result.
At the end of the day the only thing you actually need to pass through is the
error. So I would propose a new operator "->" that acts as a "resolve deref"
operator. It would be operating on the "Some" part of an Option and the "Ok"
part of a result and pass through the errors unchanged:
So essentially this:
let rv = match expr() {
Ok(tmp) => tmp.method(),
err => err,
};
Would be equivalent to:
let rv = expr->method();
Likewise for options:
let rv = match expr {
Some(tmp) => tmp.method(),
None => None,
}
Would likewise be equivalent to:
let rv = expr->method();
As a result you could only ever call this on things that return results/options
themselves.
Annoyingly enough this also means that the results need to be compatible which
is still a problem. The example there would be an IO trait that is implemented
by another system that also has its own error cases. Case in point: SSL
wrapping that wants to fail with SSL errors in addition to IO errors. I fail to
understand at the moment how library authors are supposed to deal with this.
Thoughts on this? Am I missing something entirely?
Regards,
Armin
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