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digitalmars.D.announce - Silicon Valley D Meetup January 28, 2016

reply =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
"A defense of so-called anemic domain models" by Luís Marques

   http://www.meetup.com/D-Lang-Silicon-Valley/events/228027468/

We will post a link to live streaming at the time of the meeting: 7pm 
Pacific time.

Ali
Jan 22 2016
next sibling parent =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
Reminder: This will happen in about 6 hours and 30 minutes.

Ali

On 01/22/2016 03:54 PM, Ali Çehreli wrote:

 "A defense of so-called anemic domain models" by Luís Marques

    http://www.meetup.com/D-Lang-Silicon-Valley/events/228027468/

 We will post a link to live streaming at the time of the meeting: 7pm
 Pacific time.

 Ali
Jan 28 2016
prev sibling next sibling parent reply =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
We are live now:

   https://hangouts.google.com/call/g5ohbh5b6wslyttc5a6qeleumia

Ali

On 01/22/2016 03:54 PM, Ali Çehreli wrote:

 "A defense of so-called anemic domain models" by Luís Marques

    http://www.meetup.com/D-Lang-Silicon-Valley/events/228027468/

 We will post a link to live streaming at the time of the meeting: 7pm
 Pacific time.

 Ali
Jan 28 2016
parent reply Adam D. Ruppe <destructionator gmail.com> writes:
I've been listening in on this and the talk about  nogc on 
constructors highlights the need to me of having more attribute 
inference. Yes, it works on templates, but not all methods are 
templates.

int add(int a, int b) { return a+b; }

OK, cool, but what if you want to call that in a  nogc context? 
Or a nothrow context? Or a  safe context? Won't work!

 safe nothrow  nogc
int add(int a, int b) { return a+b; }

It just gets silly listing it like that. What abotu

import std.conv;
class Foo {
    this(int a) { this.a = a; }
    int a;
}

 nogc void foo() {
    ubyte[__traits(classInstanceSize, Foo)] buffer;
    Foo foo = emplace!Foo(buffer[], 2);
}

That won't work because the ctor is not explicitly marked  nogc!


l.d(9): Error:  nogc function 'l.foo' cannot call non- nogc 
function 'std.conv.emplace!(Foo, int).emplace'


Since emplace itself is a template, it isn't the problem... it is 
Foo's constructor. It isn't a template and isn't marked  nogc, so 
it won't propagate.



You can fix it by marking ` nogc this(int a) {....}`

But isn't this getting silly? Everything needs half a dozen 
attributes!



It'd be nice if we could do some kind of implicit cast in the 
template if the function body is available for inspection. Or 
something.

In the real world, I rarely see people defensively putting  nogc 
on functions like this, but that limits down the line :(
Jan 28 2016
parent reply =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 01/28/2016 08:37 PM, Adam D. Ruppe wrote:

 I've been listening in on this


Why didn't you say hi? :) This has been the first time that we didn't 
have the attendance list open, so we didn't even know whether others 
were connected. Come to think of it, I think we were seeing just two 
connections: Luís and us. Perhaps it was showing just the attendees who 
had video enabled? Anyway...


 and the talk about  nogc on constructors highlights the need to me
 of having more attribute inference.


Is there a reason why only auto functions have attribute inference? Why 
not infer all attributes unless they are overridden by explicit attributes?


 Yes, it works on templates, but not all methods are templates.


Agreed.

Ali
Jan 29 2016
parent Adam D. Ruppe <destructionator gmail.com> writes:
On Friday, 29 January 2016 at 08:01:54 UTC, Ali Çehreli wrote:

 Why didn't you say hi? :)



There was no chat box!

I'm pretty uncomfortable with the whole video and audio thing. I 
think I sound terrible and look just as bad. I prefer reading and 
writing.



 I think we were seeing just two connections: Luís and us.


Yeah, I only saw the two boxes and myself, and I turned my camera 
+ mic off.


 Is there a reason why only auto functions have attribute 
 inference? Why not infer all attributes unless they are 
 overridden by explicit attributes?


The big reason is that for non-template functions, the body isn't 
necessarily there and it affects mangling.

So if you tried to do the whole .di thing and wrote:

void foo() { ... } // implicitly  safe implementation

and accessed it via

void foo(); // not marked, but no body so cannot be inferred...


You'd get linker errors because the bodyless one now has a 
different mangled name from being unable to infer.


This can also be relevant with inheritance:


class Base {
    void foo() { a+b; } // implicitly  safe
}

class Derived : Base {
    void foo() { *(cast(void*) 0) = 0; } // totally  system
}


What happens then? Is Derived.foo an error because it cannot 
override the implicitly  safe interface of Base.foo?

I think: yes, that's exactly what should happen.


But, what if you import an interface file again:

class Base {
    void foo();
}


Can we still make it an error? Eh, not reliably. And then the 
danger is: here, Base.foo *appears* to be  system, so the 
compiler will let you override it.

But in the file that uses it, with the full definition, the 
compiler inferred it to be  safe.


 safe useMyClass(Base base) {
    base.foo(); // allowed, it thinks foo is  safe
}



then the other module, compiled separately via bodyless 
interface, does:


useMyClass(new Derived());


...and it compiles because Derived *it believes* implements the 
Base interface correctly.... but now the  safe guarantee was just 
blown wide open.



With templates, the body must be present at *all* uses, even if 
compiled separately, so it doesn't fall victim to this, but other 
functions do bring a few worries.


(though, on the other hand, using a .di file, you could always 
just lie about the attributes anyway and the compiler trusts 
you... so maybe we aren't in that great of a position to begin 
with and this shouldn't be a blocker....)
Jan 29 2016
prev sibling parent =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 01/22/2016 03:54 PM, Ali Çehreli wrote:


 "A defense of so-called anemic domain models" by Luís Marques

    http://www.meetup.com/D-Lang-Silicon-Valley/events/228027468/


Luís gave an excellent presentation on anemic domain models (ADM) (Thank 
you Luís!):

   http://files.meetup.com/18234529/luis_marques_anemic_domain_models.pdf

This presentation made me realize why I've been struggling with clean 
OOP designs even for very simple programs (e.g. simple games like shut 
the box, master mind, etc.). I will read more on ADM starting with this one:

 
https://blog.inf.ed.ac.uk/sapm/2014/02/04/the-anaemic-domain-model-is-no-anti-pattern-its-a-solid-design/

Ali
Jan 29 2016