An interesting (or not) thing about C#'s var

[Lost User]

Sander Rossel wrote:

I believe the query changed, so that person basically changed everything after Context.Things and just forgot the call to ToList.

Your failure is staring you in the face, but you keep wanting to blame var. Also, testing is not just theoretical practice....

Sander Rossel wrote:

Yeah, neither us nor our customer can afford a second environment that's exactly like our production environment

Sounds like a scapegoat to me, but OK. Not sure if you have ever listened to some of the MS evangelicals talk about their releases and test procedures. YEs, billion dollar company. They also happen to offer "free" server space to MSDN subscribers. Your statement was way to vague to know what you are testing, but I to use an excuse of it costing too much is proven to be wrong. I can find out countless articles and examples that show testing up front is far cheaper than releasing with an issue and having to fix in production. But I am sure you know that....

Sander Rossel wrote:

I actually blame IQueryable that looks like an IEnumerable, but is really something very different. IQueryable quaks like a duck and walks like a duck, but isn't actually a duck. IQueryable breaks the Liskov's Substitution Principle (the L in SOLID) that states that any super class must behave like its base class. Only by not using var we can catch such by-design-quirks.

Ummmm no. I think you are making assumptions about your IEnumerble from using it with local memory (e.g. using it when it was on a List in memory). It follows the correct behavior as written in IEnumerable, but again you are being vague so maybe you have an actual example you care to share.

Sander Rossel wrote:

The only REAL reason to use var, where you actually HAVE to, is when you use anonymous types.

ACtually no. As the OP stated, there are others. His example is actually I good one that I have taken advantage of many times. Specifically, you do NOT need references to the namespace or library even. Anyway, this horse is a bit bloody. I have found var is a religious argument, but I have also brought many over to "the dark side" through diligent coding. I have yet to see someone be persuaded the opposite, for as I said most people use it as a scapegoat for some other failure and lack of testing.

[TheGreatAndPowerfulOz]

I'm with you on var, I use it myself when the type is obvious. But this statement

N_tro_P wrote:

It just amplifies his bad practice.

Is the only really cogent argument against using var.

#SupportHeForShe Government can give you nothing but what it takes from somebody else. A government big enough to give you everything you want is big enough to take everything you've got, including your freedom.-Ezra Taft Benson You must accept 1 of 2 basic premises: Either we are alone in the universe or we are not alone. Either way, the implications are staggering!-Wernher von Braun

[Sander Rossel]

N_tro_P wrote:

I have found var is a religious argument

Sounds pretty religious to you. I've pointed out some scenarios where NOT using var may help in catching errors early and all you did is call me a failure and a bad programmer who doesn't know what he's doing and compare free MSDN server space to actual production environments. I actually checked if you were our regular troll, but you have a little too much rep for that. Seems you're just bad mannered. I'm quite done discussing this with you. I do use var though. Probably a lot more often than you don't :)

Read my (free) ebook Object-Oriented Programming in C# Succinctly. Visit my blog at Sander's bits - Writing the code you need. Or read my articles here on CodeProject.

Simplicity is prerequisite for reliability. — Edsger W. Dijkstra

Regards, Sander

[Mycroft Holmes]

var seem way too close to the VB6 variant type so I have trouble typing it. The same applies for GOTO, just can't bring myself to use them.

Never underestimate the power of human stupidity RAH

[realJSOP]

I don't like var. If it's so goddamn wonderful, why require its use at all? Why bother even defining types at all? If I wanted to code like that, I'd use VB.

".45 ACP - because shooting twice is just silly" - JSOP, 2010
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[Lost User]

N_tro_P wrote:

By placing the cast you create a potential run time error that was not even necessary

At run-time? :)

N_tro_P wrote:

(rhetorical question actually)

Yeah, that helps clarifying the topic :thumbsup:

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^][](X-Clacks-Overhead: GNU Terry Pratchett)

[Lost User]

TheGreatAndPowerfulOz

I'm with you

Was that a pig that just flew by my window? ;P

TheGreatAndPowerfulOz

N_tro_P wrote:

It just amplifies his bad practice.

Is the only really cogent argument against using var.

But in all seriousness, that is also what I notice. That's not to say there are not places it shouldn't be used, but all of the naysayers seem to completely over generalize and just consider it "bad", and it seems this is why.

Computers have been intelligent for a long time now. It just so happens that the program writers are about as effective as a room full of monkeys trying to crank out a copy of Hamlet. The interesting thing about software is it can not reproduce, until it can.

[Lost User]

Sander Rossel wrote:

I've pointed out some scenarios where NOT using var may help in catching errors early

No you pointed out scenarios where your lack of testing was re-emphasized by not using var and then getting a different error than was even your actual problem. I would prefer having clear testing that gives clear errors of went wrong, and not use a weak type cast as a scape goat for the actual error and the lack of system testing.

Sander Rossel wrote:

all you did is call me a failure and a bad programmer

No, actually I said var has a bad rep because when a bad programmer uses it the good programmers were cringing anyways, and now cringe at var. Sort of like Pavlov's dog and the bell. There was never anything wrong with var, but you have falsely associated the two.

Sander Rossel wrote:

doesn't know what he's doing and compare free MSDN server space to actual production environments.

My profile is pretty open. You can claim I don't know what I am doing, but the chances are I have quite a bit more experience than you. Your attempted insult I shrug off with, "LMAO!"

Sander Rossel wrote:

I'm quite done discussing this with you.

You were never discussing. Your post above is proof. I gave you a chance to justify your environment rather than scapegoating it, and you attempted to use that opportunity at a childish insult. If I have learned one thing as a seasoned architect, it is there is always more to learn. I admit I could be wrong but as of yet not one of you nay sayers have actually made a solid argument other than 1. I don't like it 2. We have a team of nimkapoops that use it so I assume it is bad 3. We don't test so we incorrectly think we are protected from errors by using strong types Come up with an actual argument and THEN you have a discussion. Else, you just look like the guy mentioned in 2.

Computers have been intelligent for a long time now. It just so happens that the program writers are about as effective as a room full of monkeys trying to crank out a copy of Hamlet. The interesting thing about software is it can not reproduce, until it can.

[Lost User]

Eddy Vluggen wrote:

At run-time? :)

Yes. Are you seriously having issues over a hyphen in a poorly discussed topic in the lounge? No wonder you have issues with var.

Eddy Vluggen wrote:

Yeah, that helps clarifying the topic :thumbsup:

I thought so.

Computers have been intelligent for a long time now. It just so happens that the program writers are about as effective as a room full of monkeys trying to crank out a copy of Hamlet. The interesting thing about software is it can not reproduce, until it can.

[Lost User]

Mladen Janković wrote:

Wait a second, you mean it does not require referencing assembly or using directive for the namespace?

That is correct. This makes it very useful when building adapters connecting to DB layer and even in the usage of the adapters.

Computers have been intelligent for a long time now. It just so happens that the program writers are about as effective as a room full of monkeys trying to crank out a copy of Hamlet. The interesting thing about software is it can not reproduce, until it can.

[Richard Deeming]

Mycroft Holmes wrote:

var seem way too close to the VB6 variant type

A common misconception. var doesn't mean that your variable is untyped, or typed as object. It just means that the compiler decides what type the variable should be based on the value assigned to it when it is declared.

var s = "Hello"; // Compiles to exactly the same IL as "string s = ..."
s = 42; // Compiler error - cannot assign an Int32 to a String

Totally unlike the Variant type, where the variable could contain anything, and all calls were late-bound:

Dim s As Variant
s = "Hello" ' Oh, it's a string...
s = 42 ' Now it's a Long - that's fine...
Set s = New ADODB.Connection ' An object? No problem...

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"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

[Richard Deeming]

John Simmons / outlaw programmer wrote:

Why bother even defining types at all?

Because var doesn't mean "untyped". It means, "the type of this variable is obvious to the compiler, so I don't need to bother writing it".

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"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

[Lost User]

N_tro_P wrote:

Are you seriously having issues over a hyphen

No. Just the difference with compile-time :)

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^][](X-Clacks-Overhead: GNU Terry Pratchett)

[Lost User]

John Simmons / outlaw programmer wrote:

If it's so goddamn wonderful, why require its use at all?

It's not required. The post was showing a nice benefit. If you don't like benefits... Well, that's your problem I guess.

John Simmons / outlaw programmer wrote:

Why bother even defining types at all?

Why bother using high level languages? Why not just code in 1s and 0s? Yeah, silly question in response to a silly question. The fact is strong types are needed, but in my experience quite rarely. Weak types allow for improved architectural principles like development views and extensibility. The argument often made is the is errors that occur, but it is in fact a red herring in that the systems testability (another architectural principle) is lacking. That's not to say it has to be, but due to budget or lack of developer concern for tests or some other poorly justified reason it has been omitted from the system. The logic then becomes circular. We don't like it cause we found an error one time when someone used it. The truth is the error existed not because of var, and the nay sayers will usually acknowledge this. Where the gap is then, is on how it would have been caught or observed otherwise. Which goes back to testing. The testing should have been in place regardless, because it actually catches errors. Saying we use strong types because it catches errors is not observing the real issue. For one, strong types won't catch all of the errors. For two, proper testing would catch the same errors even if weak typed. Therefore, it is a red herring.

Computers have been intelligent for a long time now. It just so happens that the program writers are about as effective as a room full of monkeys trying to crank out a copy of Hamlet. The interesting thing about software is it can not reproduce, until it can.

[Lost User]

Your example would not have a "compile-time" error. It would result in a "run-time" error if it was a bad cast.

Computers have been intelligent for a long time now. It just so happens that the program writers are about as effective as a room full of monkeys trying to crank out a copy of Hamlet. The interesting thing about software is it can not reproduce, until it can.

[Lost User]

Eddy Vluggen wrote:

No. Just the difference with compile-time :)

Your example would not result in a "compile-time" error but in fact a "run-time" error. Proof:

public interface IThingy
{

}

public class Parent : IThingy
{

}

public class Child : Parent
{

}

public class Monkey
{

}

public class User
{
    public void Test()
    {
        var monkey = new Monkey();
        var child = (IThingy)monkey;

    }
}

This code compiles and will result in a bad casting exception. You are likely confusing concrete object casting which will result in a "compile-time" error (e.g. if monkey were cast to "Child"), but that was NOT the example you provided. You in fact specifically called out the usage of interfaces, which will result in a "run-time" error. " :) "

Computers have been intelligent for a long time now. It just so happens that the program writers are about as effective as a room full of monkeys trying to crank out a copy of Hamlet. The interesting thing about software is it can not reproduce, until it can.

[Mladen Jankovic]

Type inference[^]

GeoGame for Windows Phone | The Lounge Explained In 5 Minutes

[Jeremy Falcon]

Trust me, I've already learned that N_tro_P simply does nothing but call everyone stupid and argues. You can't win with someone on a podium thinking he's better than everyone. For what it's worth, I'm very pro var and I still agree with your points. I'll still use var personally, but I still agree with your points. So rest assured, there are pro var people out there that do listen. :-D

Jeremy Falcon

[Jeremy Falcon]

Bingo!

Jeremy Falcon

[Jeremy Falcon]

Don't confuse var with dynamic.

Jeremy Falcon