Where keyword class can be used in c#?

Question

I know 2 places where the class keyword is used in c#.

In class declaration
In generic constrains (class GenericClass where T : class)

But is there anything I've missed? It's importan to me, becouse I'm writing a program wich counts classes in a file. Can find no info in msdn or C# specification.

Edit

#if class
partial class C<T> where T : class
{
    // class!
    int @class = 123;
    string c = "class";
}
partial class C<T> where T : class {}
#else
partial class D {}
partial class D {}
partial class D {}
#endif

This is accumulation of several answers.

"class" is also usable as variable names (@class) as well as in string which I'm sure you already know. — Joshua Enfield, May 01 '12 at 22:30
You would get a more reliable count by using reflection against the assemblies, but this might be what you are looking for if you are analysing the source. — benPearce, May 01 '12 at 22:33
You could use the visual studio extension APIs to count classes. It's probably better at it than you are. — Sam Axe, May 01 '12 at 22:34
@benPearce This is good solution, that I would use in real life, but this program will be tested on realy big files (1gb), so reflection will not handle compiled assembly — er-v, May 01 '12 at 22:36
If he is counting a single file, reflection/APIs won't help him much. His only garaunteed way of counting them in a single file is to build a lightweight parser. — Joshua Enfield, May 01 '12 at 22:36
May be you have some partial classes and this causes to counting them two times. — Saeed Amiri, May 01 '12 at 22:43
@er-v Why is it you think just because the file is >=1GB that reflection or codeDOM won't handle it? — Joshua Enfield, May 01 '12 at 22:50
@JoshuaEnfield actually you right, the size of sourse file does not means anything, but number of types does. When I call GetTypes for assembly with 1 000 000 classes I get StackOverflowException. — er-v, May 01 '12 at 22:54
Have you considered [Roslyn](http://msdn.microsoft.com/en-us/roslyn)? — Brian, May 02 '12 at 13:06

score 11 · Accepted Answer · answered May 01 '12 at 22:54

11

Just counting occurences of "class" does not tell you how many classes are in a file:

#if FOO
partial class C 
{
    // class!
    int @class = 123;
    string c = "class";
}
partial class C {}
#else
partial class D {}
partial class D {}
partial class D {}
#endif

The string "class" appears eight times in there, but the file only defines a single class.

answered May 01 '12 at 22:54

Eric Lippert

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@EricLippert Well, the question is not about how to solve the problem. Partial classes is not a big problem. I can use stack and build names depends on namespaces, classes and nested classes. Is there any other places where keyword class can be used in C#? – er-v May 01 '12 at 23:07

score 4 · Answer 2 · edited May 23 '17 at 11:56

4

You might want to use something like ANTLR ( http://www.antlr.org/ ) and use for example something similar to this SO post Partial grammar for counting class count . I think it is safer than trying to write your own parser.

edited May 23 '17 at 11:56

Community

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answered May 01 '12 at 22:36

Styxxy

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score 3 · Answer 3 · edited May 23 '17 at 12:20

3

It's also possible to use class as an identifier by preceding it with an "at" sign.

int @class = 1;

I'm not saying it's advisable to write that, but you might want to consider it if you're trying to count classes.

Related

What's the use/meaning of the @ character in variable names in C#?

edited May 23 '17 at 12:20

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answered May 01 '12 at 22:30

Mark Byers

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finally i know how to give my variables the name `@var` and `@param`! – thumbmunkeys May 01 '12 at 22:31
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I know it, but keyword class is not used here. Just the _word_ class is used ) – er-v May 01 '12 at 22:33
Note that this is not only for variables but for any identifier. – Stilgar May 01 '12 at 22:34
@er-v: What else are you expecting? The two that you have listed are the _only_ two real uses of the keyword. Look in the spec... look in the documentation... it's all there. – Jeff Mercado May 01 '12 at 22:37
@JeffMercado Actually there is no place in documentation where it's clearly stated, that this is only real uses. I'm expecting that this the is only, but I can't be shure. – er-v May 01 '12 at 22:46
1

@er-v: Yes, it is. Read the grammar that is *fully* specified in the, wouldn't you know, specification. – jason May 02 '12 at 00:17
@pivotnig: Not sure about `param` off the top of my head, but you can already give your variables the name `var` (but please don't). You can even have a class named var, but future users of your code will hate you. Code like `var var = new var {q = "3"};` is legal if you have a `var` class. – Brian May 02 '12 at 13:09
@Brian thanks, you're right, `param` and `var` work as any other identifier without the @... TIL: something useless :) – thumbmunkeys May 02 '12 at 13:58

score 1 · Answer 4 · answered May 01 '12 at 23:00

1

It seems that you can have class defined as a compilation conditional symbol, e.g.

#if class
#else
#endif

...and it compiles if you define it in the project properties / build.

answered May 01 '12 at 23:00

NSGaga-mostly-inactive

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score 0 · Answer 5 · answered May 01 '12 at 22:32

0

Can't think of any other usage but remember that you can use keywords as identifiers if they are prefixed with @

answered May 01 '12 at 22:32

Stilgar

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score 0 · Answer 6 · answered May 01 '12 at 22:38

0

It's possible to use the keyword class in a generic method definition:

foo<T>(T object) where T:class

Use object, if you want to be able to pass y as anything:

foo(string x, class y) { }

answered May 01 '12 at 22:38

Lion

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foo(string x, class y) { } - does not compile, am I doing something wrong? – er-v May 01 '12 at 22:51
Perhaps some compilers don't allow this. – Lion May 01 '12 at 23:28
I could find the same thing also discussed [here](http://stackoverflow.com/questions/1293850/using-the-class-keyword-as-in-a-method-argument-in-c-sharp). – Lion May 01 '12 at 23:33
1

@Lion, or perhaps all compilers don't allow this. – svick May 01 '12 at 23:39

Where keyword class can be used in c#?

Edit

6 Answers6