Faster double parser?

[Raffaello Giulietti]

Hi,

if there's revived interest I would be glad to migrate the code to 
Skara/GitHub for a PR. The last uploaded version is still on Mercurial, 
I assume, under Brian Burkhalter's webrev folder.

But I'd also like to point out that there is a pending CSR as well.

(Sorry for the initiator of this thread: you're speaking about a parser, 
we about the opposite.)


Greetings
Raffaello



> The mailing list mangled formatting. My comments are prefixed below by “->”.
> 
> On Apr 5, 2021, at 9:52 AM, Brian Burkhalter <brian.burkhalter at oracle.com<mailto:brian.burkhalter at oracle.com>> wrote:
> 
> On Apr 5, 2021, at 4:11 AM, Andrew Haley <aph at redhat.com<mailto:aph at redhat.com><mailto:aph at redhat.com>> wrote:
> 
> On 4/5/21 9:08 AM, Alan Bateman wrote:
> On 04/04/2021 09:53, Andrew Haley wrote:
> :
> We also have a candidate for a String -> toDouble parser from Raffaello
> Giulietti:
> 
> https://mail.openjdk.java.net/pipermail/core-libs-dev/2018-March/052355.html
> 
> As far as I can see there's nothing wrong with it, but it got stuck in
> review. This was a bad failure of our review processes, I'm afraid. I
> wonder if we will do any better with this one.
> 
> Yeah, there was a lengthy discussion about this at the OpenJDK Committer
> Workshop just after FOSDEM 2020. Brian Burkhalter and Andrew Dinn had
> both put time into looking at the proposal it but the conclusion was
> that Raffaello's paper "The Schubfach way to render doubles" needed a
> review from from an expert in this area.
> 
> -> I spent some time on it a while back but got bogged down.
> 
> I wonder. The implementation has even been proved correct for floats by
> exhaustion. (Of course that's not possible for doubles.)
> 
> -> I exhaustively verified it for floats. I also ran round-trip tests for doubles which ran for days without error. Of course one can only disprove by counterexample, not prove by anecdote.
> 
> I submit, therefore, that we could at least use the float version without
> reasonable fear of breaking something.
> 
> -> That is a good suggestion.
> 
> We seem to be paralysed by this one.
> 
> Guy Steele was mentioned but I don't know if he was approached about it.
> 
> -> Indirectly.
> 
> -> Another aspect which was raised was supportability: is it sufficiently understood for us to support? On that note I would ask “Is FloatingDecimal sufficiently understood to support?” I think the answer to both questions is the same.