Game Development

Almo

22:10

@JoshPetrie gamedev.stackexchange.com/questions/112400/…

singleton alert!

You might want to answer that one

Ali.S

I honestly don't understand the fuzz about singletons....

I mean they are just globals

Almo

josh wrote an article about it

Ali.S

and I can understand people not wanting multiple instances of same class being created

Almo

can't recall the link though

Ali.S

@Almo right now I'm struggling with globals too

but just because they might cause problems later doesn't mean you shouldn't use them altogether

josh has many valid points about singletons

I remember we once had a long conversation about'em

Almo

22:14

probably twice

Ali.S

I meant me and josh :P

Almo

i meant you and josh

Ali.S

:D

maybe twice then :D

Icy Defiance

"I mean they are just globals" that's exactly what the fuss is. most of the time people should be using static things to get exactly the same functionality, but they overthink the problem and use a singleton instead.

the only thing a singleton can do that static things can't is automatic initialization, and that's only in some languages, mainly C++

something that requires automatic initialization in C++ is a totally valid use case though, which means singletons aren't inherently evil

Ali.S

22:32

@IcyDefiance it's not automatic... but lazy initialization

I mean every object is automatically initialized right?

Alexandre Vaillancourt

If they are static, yes.

(in the global scope, including static class variables)

Icy Defiance

yeah what I mean is C++ doesn't have a constructor that runs the first time you access a static variable. you can't do any complicated logic there like you can in a singleton.

C# does have a static constructor, so there is literally no reason for a singleton to ever exist in that language.

Ali.S

singletons have one big benefit though

when you are abstracting a hardware and you are sure only one instance of that hardware exist

Icy Defiance

you know only one instance of a static variable will exist too

or a whole static class in C#

Ali.S

but certain misguided programmer might create another instance of your class, and break everything

Icy Defiance

22:36

you can't create another instance of a static class. it's not possible.

Ali.S

well then C# static classes are just singletons

Icy Defiance

in C++ static classes doesn't exist, so you're right there, but C# just doesn't have that problem

Almo

METICULOUS SHIT ALERT

At Singapore Airlines, No Detail Is Too Small

►

Icy Defiance

no, C# static classes aren't singletons. singletons are an overly complicated structure with exactly the same functionality as a static class. that's my entire point here.

Fuzzy Logic

that is the difference. A static class cannot be instanced

Almo

22:38

his point is that you don't need to instance it.

I think

Ali.S

@IcyDefiance I can't even imagine how is 10 lines of code overly complicated stuff?

Almo

you get the same functionality

I use them. BUt I see his point.

Fuzzy Logic

if you make an abstract factory, you need instances because you don't know what class you are calling before-hand

they are abused though. most times a singleton is the wrong choice

Icy Defiance

class Singleton
{
    public static readonly SingletonB Instance = new SingletonB();

    public void Test()
    {
	// Code runs.
	Console.WriteLine(true);
    }
}

static class BetterThanSingleton
{
	public static void Test()
	{
		Console.WriteLine(true);
	}
}

there's two classes with exactly the same functionality

Ali.S

@IcyDefiance not really

you can create multiple instances of first one

Almo

22:42

The Singleton does not get created if you never use it.

I thought that was one of the reasons to use them

that they might not get created

Icy Defiance

@Ali.S you're right, there should be a constructor in the singleton that throws an exception when creating a second copy, but the point remains: why do that?

a static class does the same thing. just use static.

Ali.S

@IcyDefiance maybe because it's not C++?

Icy Defiance

oh hey, you do get it. so why are you pretending to argue with me?

Ali.S

class singleton
{
static singleton* getInstance(){static singleton* instance = new singleton(); return instance;}
private:
singleton(){};
}

@IcyDefiance i'm saying that static class is just a fancy wrapper over a idea, which was not hard to implement in first place

Icy Defiance

even in your example, you can keep the private constructor, scrap the singleton*, and just use only static variables

that would be functionally identical without the extra pointer

Alexandre Vaillancourt

22:46

@Ali.S You'd have to add a static keyword on your getInstance line :)

Icy Defiance

also without the requirement to call getInstance() every time you want to use it

actually the code you pasted is a perfect example of misuing a singleton, lol

Alexandre Vaillancourt

@IcyDefiance Why is that?

Icy Defiance

like I just said, keep the private constructor, scrap the singleton pointer, and just use static variables and functions. same functionality, less complicated, and it won't require you to call getInstance() all the time.

if you actually put some complicated logic inside the private constructor, then that would be a good use case for a singleton. otherwise don't bother.

Alexandre Vaillancourt

And you call everything Singleton::DoStuff( x );?

(when you use it)

Ali.S

@IcyDefiance that's even worst... I mean what if after some time you added a new hardware, and now you need to have multiton instead of singleton?

Icy Defiance

22:51

Singleton::DoStuff(x):
vs
Singleton::getInstance().DoStuff(x);

exactly the same functionality, but one is more complicated.

this is 100% objective, not a matter of opinion. not sure why this is so hard to get.

Fuzzy Logic

Why get an instance if you are referencing the class explicitly?

Alexandre Vaillancourt

Yeah, well if your singleton has multiple class attributes, it's multiple static class attributes VS one static variable. And you can do auto sing = Singleton::getInstance(); sing->doSttuff(x); which you can't if you declare everything as static.

Fuzzy Logic

db = MySQL::getInstance();

Ali.S

@IcyDefiance it's not complicated (as far as I can see) just few more characters to type!

and it's less versatile.

Fuzzy Logic

replace MySQL with another database implementation

Icy Defiance

22:56

in that case, it becomes
Singleton::DoStuff(x);
Singleton::DoMoreStuff(y);
vs
auto sing = Singleton::GetInstance();
sing->DoStuff(x);
sing->DoMoreStuff(y);

Fuzzy Logic

or 10 potential db implementations

Icy Defiance

still the same functionality, singleton is still more complicated

@FuzzyLogic that would be the one and only exception, which I've mentioned several times already. MySQL likely does some initialization things the first time an instance is created, to connect to the database and so on. that can't be done neatly with static methods.

Fuzzy Logic

that's not the point, it's separation of concerns

Icy Defiance

although I think that would be weird, because you wouldn't be able to close a connection...

yeah I'd still be surprised at that design

Fuzzy Logic

the rest of the code doesn't care if you are using MySQL or CSV

or shouldn't need to care

Icy Defiance

23:00

oh I see. that's actually a good point.

a rare use case, but still one that exists

Alexandre Vaillancourt

@IcyDefiance I think the main concern, as you say, is about the construction. When is it constructed?

Aidan Mueller

Why do people say "nuke" instead of microwave? It's not ionizing.

That's why I think we should refer to the microwave as the 2.4, since that's what frequency it uses.

"Yes, just stick it in the 2.4 for for 3 minutes".

Fuzzy Logic

using singletons should be rare. it's one of those things that is abused more often than not because of a lack of understanding when to use them and what should be used instead.

Icy Defiance

@AidanMueller because a microwave uses radiation. electromagnetic radiation, not nuclear, but most people don't know the difference.

Aidan Mueller

Yeah, but I still think it's weird.

Fuzzy Logic

23:07

I've been taught to think of them like globals. Do use them when needed but if you are considering it, think HARD because it's uaully the wrong decision

Noctrine

@AidanMueller Radiation, Really wasn't generally usable until the late 60s - and by that point radiation meant nukes to the US population.

Icy Defiance

and yeah FL you're exactly right

Aidan Mueller

People say radiation. Really, visible light is radiation.

@Noctrine Makes sense.

Alexandre Vaillancourt

Duke Microwavem 3D would have been less popular I guess...

Noctrine

@AidanMueller And so is sound, and then you know - just a general byproduct of being.

Icy Defiance

23:09

the way I see singletons is like, if you're trying to walk across a room and grab something on the other side, but you refuse to just walk straight across the room. instead you skirt the outside, next to the walls, because it feels like the problem shouldn't be as easy as just walking straight.

3

Noctrine

But following WWII, Radiation is "Radiation"

Icy Defiance

now if there's a hidden trap in the middle of the room then great, you have a reason to walk around it, but that's really rare. most of the time just walk straight. it's much easier.

Alexandre Vaillancourt

I use singletons to 1) force that there is only one instance available and 2) avoid passing shit around (generaly because I only need one instance)

user4704

@Almo That's because it's gone.

Icy Defiance

@AlexandreVaillancourt and both of those are the wrong reasons, lol. we just went over this.

whatever, I'm not gonna repeat it all

Aidan Mueller

23:12

@AlexandreVaillancourt inb4 microwave simulator 2015.

Alexandre Vaillancourt

@IcyDefiance I was probably AFK :)

Icy Defiance

you were replying to me...

Aidan Mueller

I just don't use singletons. The first time I saw one I thought it was ~~retarded~~ gits.

Alexandre Vaillancourt

@IcyDefiance lol really? hmm... something's wrong then

Icy Defiance

17 mins ago, by Icy Defiance

in that case, it becomes
Singleton::DoStuff(x);
Singleton::DoMoreStuff(y);
vs
auto sing = Singleton::GetInstance();
sing->DoStuff(x);
sing->DoMoreStuff(y);

that sums it all up

Aidan Mueller

23:14

I was like "why would you have a static function that returns an instance?"

Alexandre Vaillancourt

Ah, yeah, but I still have the concern of when is your static initialized. It can't be constructed.

Icy Defiance

there you go. that's the right reason to use a singleton. if the construction actually matters.

Alexandre Vaillancourt

Yes. Sorry, it was implied in my two reasons :)

When I write a class that will be instanciated, but a method does not use any class attributes, I write it as as static method.

But yeah, if a class only offers services without needing an explicit initialization of the state, sure, static all the way!

Icy Defiance

I just have to emphasize that "I only want one instance" is a horrible reason to make a singleton, because sooo many people have turned that into dogma and started writing singletons everywhere when things really should just be static.

and that dogma created an opposing dogma, "all singletons are evil"

equal and opposite reaction I guess

oh well, back to advent of code. gotta finish today's problems.

Alexandre Vaillancourt

Yeah. Generally, I'll have a "singleton manager". This will be the only 'enforced singleton', from which you'll be able to fetch pseudo-singleton: instances that will be unique, but not 'unique enforced', if I may put it this way.

Icy Defiance

23:21

can't use linq this time without being completely evil. so sad. :(

Aidan Mueller

There can only be one taco.

Alexandre Vaillancourt

gone AFK

Aidan Mueller

I think I believe in the all singletons are evil dogma.

I kind of believe that objects should exist just fine by them self. If they don't, you are misrepresenting the object.

Wardy

i only ever have 1 singleton in anything i write these days ... my DI provider

usually ninject

then i build my stacks using conventions so even that is kept lightweight

Aidan Mueller

It seems as though there is a bit of a "object oriented programming is evil" dogma these days too.

Icy Defiance

23:29

wait...really? but everything is object oriented to some extent.

Aidan Mueller

I would say that there is actually a "abusing OO programming is evil" fact.

Wardy

oop is considered best practice round here

Fuzzy Logic

that's because it's too dogmatic

Wardy

you can things like over user a particular concept

like i've seen inheritance stacks 20 types deep

there's just no need for excessive inheritence

Fuzzy Logic

often there is no need for OOP at all but OOP languages don't like to cooperate with other programming paradigms

Icy Defiance

23:31

yeah I've never worried too much about following all the oop design pattern stuff. most of the time I just do what makes sense and it works fine.

not sure I'd call it evil, but maybe overrated

design patterns in general are probably overrated. if it makes sense it's probably good.

user4704

Apparently the chat quicklink only works in comments.

user4704

Not post bodies.

user4704

@Wardy Excessive inheritance isn't always the problem, sometimes it's just dumb inheritance one level deep.

Aidan Mueller

@IcyDefiance I am starting to move to "does it make sense for this to be an object".

Wardy

@JoshPetrie yeh seen that too

or literally no inheritance where something should be

user4704

23:35

@Almo I replied anyway though

Aidan Mueller

The reason why

Almo

cool :)

Aidan Mueller

Nov 30 at 17:05, by Tyyppi_77

Java sucks.

is because everything has to be an object.

Wardy

@AidanMueller thats not the reason ... c# is pretty awesome and that has the same rule

Icy Defiance

yeah I don't think that's really a bad thing. like in C# you can make an extension method for an int and be like "if (i.IsOdd())"...not that you should actually do that, but you can, lol

Aidan Mueller

23:39

Hmm. Sounds kind of cool.

I don't like C# because I associate it with MS.

Icy Defiance

it's a shame that it doesn't work too well on linux yet, but as a language it's by far the nicest one I've ever used. I'm spoiled by it.

Aidan Mueller

What's your opinion on CPP?

Icy Defiance

MS is working on making it cross-platform though. There's some beta stuff out there like vnext.

Wardy

@IcyDefiance c# runs fine on linux

Icy Defiance

it runs on linux, but "fine" is situational. depends on what the program is.

Wardy

23:42

?

Icy Defiance

like the ASP.NET MVC stuff doesn't work at all

Wardy

aspnet is a mess atm

even on windows thats a shit storm

especally when you consider all that web api stuff and odata framework they have

all aweseome in concept but dably engineered

Aidan Mueller

I'm not really going with it until there is a good FLOSS alternative. I like my programming stuff to be FOSS.

Wardy

FOSS?

Icy Defiance

@AidanMueller If C# didn't exist I'd probably use C++ all the time. It's sometimes annoying to work with, but nothing horrible.

except linker errors...

Wardy

23:44

@IcyDefiance me too i suspect ... and i don't know c++ pretty much at all

i just know i wont go near java after that whole issue with salesforce a few years back

Fuzzy Logic

@Wardy FOSS = Free Open Source Software

C# is basically proprietary, like Java. You are at the whim of Microsoft

Wardy

@FuzzyLogic aspnet + mvc is

roslyn (the new cross platform compiler for c#) is also FOSS

Icy Defiance

roslyn is open source, but not really free

Wardy

its completely free

go to github download the source, do what you want

Fuzzy Logic

yea, MS has at least made the language spec an open standard

so it's not a lock-in like Java

Icy Defiance

23:49

oh shit, Roslyn is released under Apache 2.0

it really is free

Wardy

no idea why people get hung up on paying licence fees to microsoft

Icy Defiance

that's pretty cool

Fuzzy Logic

it's not the paying part, it's the hands-tied part

Wardy

i mean ... these days its more expensive to have al inux box than a windows one

@FuzzyLogic the entire plan from day 1 with c~ was to make a 4th gen version of c++ with java like syntax

hands tied?

Icy Defiance

@FuzzyLogic no look up Apache 2.0. it's more free than most FOSS. way better than the GPL crap.

Fuzzy Logic

23:50

vendor lock-in

Icy Defiance

it's a really permissive license

Wardy

@FuzzyLogic C# is not vendor locked as a language in any way

nor is the compiler for it

Fuzzy Logic

if roslyn catches on, that would be good but right now it's still MS

Wardy

its a completely free and open standard

@FuzzyLogic created by yes, but there's no lock in

Icy Defiance

the latest version of VS is using roslyn, isn't it? I'd say it already caught on.

Wardy

23:52

@IcyDefiance it can do ... dependso n the version of the clr you tell your code to compile against

you can actually choose not to use it if you prefer

it gets a bit confusing ... the clr has a version and the c# language has a version

the roslyn compiler was built to allow clr compliant compilation of c# 6 and higher

for .net 4.0 or later

Icy Defiance

regardless, if you can take any C# code and compile it against roslyn, and you can modify and redistribute roslyn however you want, and even profit from your modifications, that seems pretty free to me

Wardy

@IcyDefiance i believe apache licencing allows for that

Icy Defiance

yeah it does

Wardy

which is what roslyn is shared under

you can even commit core code changes to it through github i believe

become a contributor

Fuzzy Logic

yea, C# is getting there

Icy Defiance

23:55

all that said, it's still a little iffy on linux, which is a shame. that's pretty much the only reason to not use it right now, and it should change over the next couple years.

well not the only reason

Wardy

iffy?

Icy Defiance

explained that already. not everything works perfectly.

Wardy

write better code?

Icy Defiance

dude. scroll up. I already gave you an example that can't be solved by doing anything "better".

Wardy

like the ASP.NET MVC stuff doesn't work at all

that's not true

I have deployed mvc sites on my linux based nas

running mvc on apache is ... interesting

but i can assure you it does work

Icy Defiance

23:58

huh, maybe apache does something different. I spent like 2 weeks trying to make it work with nginx and it just didn't.

Wardy

not sure ... i don't know anything about nginx but it works pretty well with apache

Icy Defiance

mono's efforts mainly went toward the other structure, I forget what it's called.

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