Local functions infer attributes?

[Manu via Digitalmars-d]

On 29 September 2014 18:02, Andrei Alexandrescu via Digitalmars-d
<digitalmars-d at puremagic.com> wrote:
> On 9/28/14, 5:38 PM, Manu via Digitalmars-d wrote:
>>
>> I was out of town (was on my phone), and now I'm home with 2 guests,
>> and we're working together. I can't sit and craft a pile of example
>> cases until I'm alone and have time to do so. I haven't ignored it,
>> but I need to find the time to give you what you want.
>
>
> Thanks, don't feel under any obligation express or implied to follow
> through.

Well, after your unflattering caricature, I intend to take the time to
try and craft some good examples of various cases.
I also have a strong suspicion (valid or otherwise) that there is
literally nothing I could do to convince you, no matter the quality of
my evidence.
There will always be the "it's too late", "it's a breaking change!",
defence. Unless you and Walter are both invested in a change, I'm
pretty certain it's impossible.
So, your observation may well have been fair. Perhaps that is a true
pattern of mine, but I don't think 'I'm just a dick like that', I
think there is reason behind it.

There is certainly time in the past where I've gone to great lengths
to try and prove my cases. In more recent times, and as my (few)
outstanding daily problems with the language have become more
controversial, I've become fairly convinced that such effort on my
part is just wasting my time, and only serves as a process for me to
highlight my frustrations to myself.
You obviously don't approach programming the same way I do, I can't
appeal to you.

Upon closer examination of my mood and feelings interacting with this
forum recently, I realise that this is a significant factor in my
interaction, although perhaps being mostly subconscious. Ie, I'm more
likely to disappear and try and get some work done, than spend the
time trying to win a futile argument.
I did try very hard to extract myself from this NG, but it seems it's
very hard to resist! When topics I care about appear, or when I'm just
wildly frustrated about something that agitates me on a daily basis, I
keep coming back! >_<

Point is, I feel like I've been an engaged member of this community
for a long time now, but I feel like I have practically nothing more
to add.
My experience and industry use cases are no longer interesting,
they've presented any value that they had already. I get the feeling
I've affected all of the change that I am capable of, and I need to
decide if I'm happy with D as is, or not, rather than maintain my
ambient frustration that it's sitting at 99%, with the last 1%
unattainable to me unless I fork the language for my own use :/

Trouble for me is, I've invested so much time now. I find myself in a
very awkward situation where I'm too far in... I can't go back to C++,
but the situation is such that I'll never convince the rest of my
colleagues to jump on board. Believe it or not, I'm a lot more
reasonable (and patient) than most.


I'm quite certain that these days, that thing that Scott Myers
mentioned about the C++ committee; where practically anything can be
used to justify anything, so getting changes approved is mostly an
appeal to the emotional state of the people in charge, is already
present in D.


>> That said, my friend encountered one of my frequently recurring pain
>> cases himself yesterday:
>> struct S(T...)
>> {
>>    void f(T args) {}
>> }
>>
>> S!(int, ref S) fail; // <-- no clean way to do this. I need this very
>> frequently, and he reached for it too, so I can't be that weird.
>
>
> I understand. The short answer to this is D cannot do that and we cannot
> afford to change the language to make it do that.
>
> There are two longer answers.
>
> The first longer answer is there are ways to do that if it's a necessity, as
> you know and probably did. I agree it's not clean/easy.
>
> The second longer answer is if you do this it means you're trying to write
> C++ in D: in C++ ref is part of the type (well... sort of) and therefore
> someone coming from C++ and translating the respective designs into D will
> find the change frustrating.

What about someone *interacting* with C++, not just 'coming from'?
I also interact with Lua and C# a lot. Lua is ref by nature, C# also
uses ref a lot.
In 6 years, the only time I've found an opportunity to use D in
isolation, is a small webserver in vibe.d.

My opinion is that ref is agreed to be critically important, as
demonstrated to me by all the other languages I use.


> I've seen this pattern several times. Most recent was in conjunction with
> iterators vs. ranges. There's discussion going on in C++ circles about
> adding ranges to C++. One common issue raised by people gravitates around
> designs where the choice of using iterators is long foregone, and would
> think that replacing iterators with ranges throughout should just work. Take
> a look: http://article.gmane.org/gmane.comp.lib.boost.devel/191978
>
> The reality is algorithms implemented with ranges look different from
> algorithms implemented with iterators. Similarly, generic code with D will
> look different from generic code with C++. Our hope is, of course, that all
> told range-based and D-generics code has advantages going for it, but the
> most dramatic of those advantages most certainly won't be discovered and
> reaped in designs that are copies of the respective C++ ones.

I'm not writing ranges or generics. Those things are fine, and they
are also self-contained within D.

I obviously use D completely differently to you, and value an entirely
different set of features.
Trust me, I'm not copying designs from C++, I use D specifically for
use cases where C++ is utterly impotent.

For me, 80% of generic code is about binding things (and a further 15%
is serialisation). As said before, C++, C#, Lua; it is super-common in
gamedev for the ecosystem to be made of (at least) 3 significant
languages.
Bindings are traditionally cumbersome, brittle, and one of the biggest
hassles, frustrations, sources of time/productivity loss using C++ for
game tech, is maintaining such bindings.
D is the only language I know powerful enough to automate that mess.
This is why D was attractive to me, and it is still why D is
attractive to me. I _can't escape ref_ when writing this sort of code,
and I write a lot of it.
I don't think it's at all fair to say "I'm using D wrong", or "stop
trying to be a C++ user in D", that's not the case here..


It's also a bit strange to hear you say all this when the key focus of
development at the moment is "C++, GC", "C++, GC".


> So you can't be that weird and neither is your friend, but I speculate that
> both of you have a solid C++ background :o).

No, I think we're pretty normal, and populace.


> About this situation in particular, yes, ref being part of the type does
> help this declaration, but overall as a design decision for the C++
> programming value its value is questionable. T& is not a first class type
> and that hurts everyone everywhere - you can't create a value of that types,
> and virtually all parts of the language have special rules telling what
> happens when the actual type is a reference type.

You're saying T& is not a first-class type and hurts everyone
everywhere, I agree, and D is no different, except it is even worse.
I'd like to explore ref as a first-class type. Do you have reason to
believe that's completely unworkable? I'm not suggesting to clone
C++'s design. I think there's room for a design that improves on C++.


> I think Walter made the right call here and we shouldn't change anything.

This pretty much validates my opening suspicion. What do I do? STFU
and deal with it?

I suspect you'd think very differently if you worked with the people I
do, have the conversations with colleagues I have, and struggled with
the code I have for as long as I have. I dread to think how much ref
has cost me in $/hr terms.
You make ref sound worthless. Is there actually any situation where
you find value in ref?
If it's meaningless to you, and so 'un-D', why not let it have useful
meaning for those who find it significant, important even? :/