On Fri, Feb 20, 2015 at 5:08 PM, Pierre Joye <pierre....@gmail.com> wrote:
> hi Dmitry, > > On Thu, Feb 19, 2015 at 11:13 PM, Dmitry Stogov <dmi...@zend.com> wrote: > > On Fri, Feb 20, 2015 at 4:57 AM, Anthony Ferrara <ircmax...@gmail.com> > > wrote: > > > >> Larry, > >> > >> > Anthony, can you expand here at all about the practical benefits of > >> > strong-typing for variable passing for the compiler? That seems to be > >> the > >> > main point of contention: Whether or not there are real, practical > >> benefits > >> > to be had in the compiler of knowing that a call will be in "strict > >> mode". > >> > (If there are, then the split-mode makes sense If there are not, then > >> > there's little benefit to it.) > >> > >> For the normal compiler & engine there will be no benefit for the > >> foreseeable future. > >> > >> For a tracing JIT compiler, there will be no advantage. > >> > >> For a local JIT compiler, there can be some optimizations around > >> reduced conversion logic generated (and hence potentially better cache > >> efficiency, etc). A guard would still be generated, but that's a > >> single branch rather than the full cast logic. This would likely be a > >> small gain (likely less than 1%, possibly significantly less). > >> > >> For a AOT compiler (optimizing compiler), more optimizations and > >> therefore gains can be had. The big difference here is that type > >> assertions can be done at compile time. > > > > > > AOT compiler that know type of passed argument and expected parameter > type, > > may eliminate guard check independently on hint semantic (strong or > week). > > If you don't know first or second you'll have to generate guard code > anyway > > independently from hint semantic (strong or week). Is this wrong? > > > > We may introduce strong type hints because of your mistake. > > > May, could, would, all that are totally irrelevant to the debate about > type hinting. The speed benefit is not significant. > What is significant? Miracle ability of static analyzes for AOT? I think we can agree on that, and we did as far as I can tell :) > I didn't agree with you. Probably, I told that performance impact of run-time switch of type hinting semantic is slightly negative and it would be great to fix it if possible. > > > >> However, I think making this decision based on performance is the > >> incorrect way of doing it. For the Zend engine, there will be no > >> discernible difference between the proposals. It's a red herring. The > >> difference I would focus on is the ability to statically analyze the > >> code (with the benefits that comes with). > >> > > > > Completely agree, changing language for compiler is not fair. > > It's clear that statically typed languages are more suitable but we won't > > make PHP statically typed. > > Also, modern JS engines showed - what they may do without typing. > > Let put things correctly please: > > > In my opinion strict type hints may be useful for program verification, > but > > again, I wouldn't like to change the whole language semantic > > > > We are talking about arguments handling here. Not the whole language > semantic. The way the language works will stay the same. I am not > writing that for you but for all other who may be misinterpret your > reply. > > > just to get few unit tests out of the box. > > Strict types handling for arguments goes way beyond having a few units > tests. It would very good if one single point of the argumentation is > used to generalize a cons argument. That makes no sense and it simply > goes down a way I would really not like to see again. > I didn't hear any arguments for strict typing except for program verification and static analyzes, may be I missed. Please, tell me few use cases, may be it'll change my mind :) Thanks. Dmitry. > Cheers, > -- > Pierre > > @pierrejoye | http://www.libgd.org >
