Mixing
String interpolation - what does the @ sign inside the curly braces do?
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up vote
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Consider:
string newline = "rn";
Console.WriteLine($"Hello without atnewlinehow are you?");
Console.WriteLine($"Hello with at@newlinehow are you?");
The output of both lines is identical. The newline is always printed as a newline.
Hello without at
how are you?
Hello with at
how are you?
So when do I need the at sign inside the curly braces?
c# .net
edited Aug 31 at 13:52
Peter Mortensen
12.9k1983111
asked Aug 31 at 8:57
Thomas
1,0001833
 |Â
show 2 more comments
up vote
19
down vote
favorite
Consider:
string newline = "rn";
Console.WriteLine($"Hello without atnewlinehow are you?");
Console.WriteLine($"Hello with at@newlinehow are you?");
The output of both lines is identical. The newline is always printed as a newline.
Hello without at
how are you?
Hello with at
how are you?
So when do I need the at sign inside the curly braces?
c# .net
edited Aug 31 at 13:52
Peter Mortensen
12.9k1983111
asked Aug 31 at 8:57
Thomas
1,0001833
1
Possible duplicate: stackoverflow.com/questions/6134547/…
– Keyur Ramoliya
Aug 31 at 8:59
5
This one is related
– Mong Zhu
Aug 31 at 9:00
7
@KeyurRamoliya: It's definitely not a duplicate of that. That's about verbatim string literals. This isn't one of those. It's using@with an identifier, which is typically used with keywords, e.g.@thisas the name of the first parameter in an extension method.
– Jon Skeet
Aug 31 at 9:00
@KeyurRamoliya I don't think that's a correct duplicate. HimBromBeere's answer is correct.
– Sweeper
Aug 31 at 9:01
Reference for verbatim string here.
– Tetsuya Yamamoto
Aug 31 at 9:01
 |Â
show 2 more comments
up vote
19
down vote
favorite
up vote
19
down vote
favorite
Consider:
string newline = "rn";
Console.WriteLine($"Hello without atnewlinehow are you?");
Console.WriteLine($"Hello with at@newlinehow are you?");
The output of both lines is identical. The newline is always printed as a newline.
Hello without at
how are you?
Hello with at
how are you?
So when do I need the at sign inside the curly braces?
c# .net
edited Aug 31 at 13:52
Peter Mortensen
12.9k1983111
asked Aug 31 at 8:57
Thomas
1,0001833
Consider:
string newline = "rn";
Console.WriteLine($"Hello without atnewlinehow are you?");
Console.WriteLine($"Hello with at@newlinehow are you?");
The output of both lines is identical. The newline is always printed as a newline.
Hello without at
how are you?
Hello with at
how are you?
So when do I need the at sign inside the curly braces?
c# .net
edited Aug 31 at 13:52
Peter Mortensen
12.9k1983111
asked Aug 31 at 8:57
Thomas
1,0001833
edited Aug 31 at 13:52
Peter Mortensen
12.9k1983111
edited Aug 31 at 13:52
Peter Mortensen
12.9k1983111
edited Aug 31 at 13:52
Peter Mortensen
12.9k1983111
12.9k1983111
asked Aug 31 at 8:57
Thomas
1,0001833
asked Aug 31 at 8:57
Thomas
1,0001833
asked Aug 31 at 8:57
Thomas
1,0001833
1,0001833
1
Possible duplicate: stackoverflow.com/questions/6134547/…
– Keyur Ramoliya
Aug 31 at 8:59
5
This one is related
– Mong Zhu
Aug 31 at 9:00
7
@KeyurRamoliya: It's definitely not a duplicate of that. That's about verbatim string literals. This isn't one of those. It's using@with an identifier, which is typically used with keywords, e.g.@thisas the name of the first parameter in an extension method.
– Jon Skeet
Aug 31 at 9:00
@KeyurRamoliya I don't think that's a correct duplicate. HimBromBeere's answer is correct.
– Sweeper
Aug 31 at 9:01
Reference for verbatim string here.
– Tetsuya Yamamoto
Aug 31 at 9:01
 |Â
show 2 more comments
1
Possible duplicate: stackoverflow.com/questions/6134547/…
– Keyur Ramoliya
Aug 31 at 8:59
5
This one is related
– Mong Zhu
Aug 31 at 9:00
7
@KeyurRamoliya: It's definitely not a duplicate of that. That's about verbatim string literals. This isn't one of those. It's using@with an identifier, which is typically used with keywords, e.g.@thisas the name of the first parameter in an extension method.
– Jon Skeet
Aug 31 at 9:00
@KeyurRamoliya I don't think that's a correct duplicate. HimBromBeere's answer is correct.
– Sweeper
Aug 31 at 9:01
Reference for verbatim string here.
– Tetsuya Yamamoto
Aug 31 at 9:01
1
1
Possible duplicate: stackoverflow.com/questions/6134547/…
– Keyur Ramoliya
Aug 31 at 8:59
Possible duplicate: stackoverflow.com/questions/6134547/…
– Keyur Ramoliya
Aug 31 at 8:59
5
5
This one is related
– Mong Zhu
Aug 31 at 9:00
This one is related
– Mong Zhu
Aug 31 at 9:00
7
7
@KeyurRamoliya: It's definitely not a duplicate of that. That's about verbatim string literals. This isn't one of those. It's using
@ with an identifier, which is typically used with keywords, e.g. @this as the name of the first parameter in an extension method.– Jon Skeet
Aug 31 at 9:00
@KeyurRamoliya: It's definitely not a duplicate of that. That's about verbatim string literals. This isn't one of those. It's using
@ with an identifier, which is typically used with keywords, e.g. @this as the name of the first parameter in an extension method.– Jon Skeet
Aug 31 at 9:00
@KeyurRamoliya I don't think that's a correct duplicate. HimBromBeere's answer is correct.
– Sweeper
Aug 31 at 9:01
@KeyurRamoliya I don't think that's a correct duplicate. HimBromBeere's answer is correct.
– Sweeper
Aug 31 at 9:01
Reference for verbatim string here.
– Tetsuya Yamamoto
Aug 31 at 9:01
Reference for verbatim string here.
– Tetsuya Yamamoto
Aug 31 at 9:01
 |Â
show 2 more comments
2 Answers
2
active
oldest
votes
up vote
26
down vote
accepted
$"Hello myValue " is an interpolated string which was introduced in C#6. In your case this is equivalent to a call to String.Format("Hello 0", myValue).
The verbatim (@) is needed when your variable has the same name as a keyword, which, as far as I know, newline is not. However the following would cause a compiler-error:
String.Format("Hello 0", if)
whilst this won´t:
String.Format("Hello 0", @if)
Here the verbatim tells the compiler that if is the name of a variable, not the if-keyword.
So you don´t need the verbatim in your case, because newline is not a keyword. Or in other words your code is equivalent to this:
Console.WriteLine("Hello with at0how are you?", @newline);
which is a valid (even though redundant) use of the verbatim.
For further information refer to the documentation about string-interpolation.
answered Aug 31 at 8:59
HimBromBeere
21.7k33156
1
$is not really a shortcut forString.Formatit basically returns aFormattableStringwhich in many ways differs fromString.Format
– Mateusz
Aug 31 at 9:09
@Mateusz Doesn´tString.Formatreturn anFormatableStringalso?
– HimBromBeere
Aug 31 at 9:10
Not quite the same,$can return astringalready processed,FormattableStringwhich then can be used to process it on how you want/need it to andIFormattablewhich is the only one that really relates toString.Formatmethod but it's not a shortcut, more like a long road to format.
– Mateusz
Aug 31 at 9:13
1
$"Hello myValue"is in fact also a shortcut tostring.Formatsince the compiler will only use theFormattableStringif the only target for the expression is aFormattableString. So the compiler will reformat this directly to astring.Formatcall.
– Lasse Vågsæther Karlsen
Aug 31 at 9:14
1
It is also worth to mention about interoperability between different languages. Keyword in one language is not necessarily the keyword in the second.
– Karol
Sep 1 at 12:11
 |Â
show 19 more comments
up vote
13
down vote
It's a redundant verbatim prefix. From the C# specification:
The prefix "@" enables the use of keywords as identifiers, which is useful when interfacing with other programming languages. The character @ is not actually part of the identifier, so the identifier might be seen in other languages as a normal identifier, without the prefix. An identifier with an @ prefix is called a verbatim identifier. Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style.
A use case would be if you would want to write a function like this:
private void print(string @string) => Console.WriteLine(@string);
Normally you would not be able to name an identifier string because it is a reserved keyword. The @ prefix enables you to do so.
edited Aug 31 at 13:54
Peter Mortensen
12.9k1983111
answered Aug 31 at 9:01
ChristianMurschall
907315
4
Important part is "The character @ is not actually part of the identifier" because that explains why it compiles even if the variable doesn't have it.
– Tim Schmelter
Aug 31 at 9:08
4
Another part that I find important is "Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style." So@newlineis tolerated but misleading/confusing.
– Jeppe Stig Nielsen
Aug 31 at 9:40
I note that your example does not match the text you've quoted from the specification, and that this is a very poor use case. The purpose of this feature is not to allow you to make a formal parameter called@stringbecause that would be a bizarre thing to do. The purpose of the feature is to allow you to, say, extend a third-party class written in a non-C# language that has a virtual member calledstring. You need to be able to sayclass D : ThirdParty public override void @string() .... That would be a by-design use case.
– Eric Lippert
Aug 31 at 21:13
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
26
down vote
accepted
$"Hello myValue " is an interpolated string which was introduced in C#6. In your case this is equivalent to a call to String.Format("Hello 0", myValue).
The verbatim (@) is needed when your variable has the same name as a keyword, which, as far as I know, newline is not. However the following would cause a compiler-error:
String.Format("Hello 0", if)
whilst this won´t:
String.Format("Hello 0", @if)
Here the verbatim tells the compiler that if is the name of a variable, not the if-keyword.
So you don´t need the verbatim in your case, because newline is not a keyword. Or in other words your code is equivalent to this:
Console.WriteLine("Hello with at0how are you?", @newline);
which is a valid (even though redundant) use of the verbatim.
For further information refer to the documentation about string-interpolation.
answered Aug 31 at 8:59
HimBromBeere
21.7k33156
1
$is not really a shortcut forString.Formatit basically returns aFormattableStringwhich in many ways differs fromString.Format
– Mateusz
Aug 31 at 9:09
@Mateusz Doesn´tString.Formatreturn anFormatableStringalso?
– HimBromBeere
Aug 31 at 9:10
Not quite the same,$can return astringalready processed,FormattableStringwhich then can be used to process it on how you want/need it to andIFormattablewhich is the only one that really relates toString.Formatmethod but it's not a shortcut, more like a long road to format.
– Mateusz
Aug 31 at 9:13
1
$"Hello myValue"is in fact also a shortcut tostring.Formatsince the compiler will only use theFormattableStringif the only target for the expression is aFormattableString. So the compiler will reformat this directly to astring.Formatcall.
– Lasse Vågsæther Karlsen
Aug 31 at 9:14
1
It is also worth to mention about interoperability between different languages. Keyword in one language is not necessarily the keyword in the second.
– Karol
Sep 1 at 12:11
 |Â
show 19 more comments
up vote
26
down vote
accepted
$"Hello myValue " is an interpolated string which was introduced in C#6. In your case this is equivalent to a call to String.Format("Hello 0", myValue).
The verbatim (@) is needed when your variable has the same name as a keyword, which, as far as I know, newline is not. However the following would cause a compiler-error:
String.Format("Hello 0", if)
whilst this won´t:
String.Format("Hello 0", @if)
Here the verbatim tells the compiler that if is the name of a variable, not the if-keyword.
So you don´t need the verbatim in your case, because newline is not a keyword. Or in other words your code is equivalent to this:
Console.WriteLine("Hello with at0how are you?", @newline);
which is a valid (even though redundant) use of the verbatim.
For further information refer to the documentation about string-interpolation.
answered Aug 31 at 8:59
HimBromBeere
21.7k33156
1
$is not really a shortcut forString.Formatit basically returns aFormattableStringwhich in many ways differs fromString.Format
– Mateusz
Aug 31 at 9:09
@Mateusz Doesn´tString.Formatreturn anFormatableStringalso?
– HimBromBeere
Aug 31 at 9:10
Not quite the same,$can return astringalready processed,FormattableStringwhich then can be used to process it on how you want/need it to andIFormattablewhich is the only one that really relates toString.Formatmethod but it's not a shortcut, more like a long road to format.
– Mateusz
Aug 31 at 9:13
1
$"Hello myValue"is in fact also a shortcut tostring.Formatsince the compiler will only use theFormattableStringif the only target for the expression is aFormattableString. So the compiler will reformat this directly to astring.Formatcall.
– Lasse Vågsæther Karlsen
Aug 31 at 9:14
1
It is also worth to mention about interoperability between different languages. Keyword in one language is not necessarily the keyword in the second.
– Karol
Sep 1 at 12:11
 |Â
show 19 more comments
up vote
26
down vote
accepted
up vote
26
down vote
accepted
$"Hello myValue " is an interpolated string which was introduced in C#6. In your case this is equivalent to a call to String.Format("Hello 0", myValue).
The verbatim (@) is needed when your variable has the same name as a keyword, which, as far as I know, newline is not. However the following would cause a compiler-error:
String.Format("Hello 0", if)
whilst this won´t:
String.Format("Hello 0", @if)
Here the verbatim tells the compiler that if is the name of a variable, not the if-keyword.
So you don´t need the verbatim in your case, because newline is not a keyword. Or in other words your code is equivalent to this:
Console.WriteLine("Hello with at0how are you?", @newline);
which is a valid (even though redundant) use of the verbatim.
For further information refer to the documentation about string-interpolation.
answered Aug 31 at 8:59
HimBromBeere
21.7k33156
$"Hello myValue " is an interpolated string which was introduced in C#6. In your case this is equivalent to a call to String.Format("Hello 0", myValue).
The verbatim (@) is needed when your variable has the same name as a keyword, which, as far as I know, newline is not. However the following would cause a compiler-error:
String.Format("Hello 0", if)
whilst this won´t:
String.Format("Hello 0", @if)
Here the verbatim tells the compiler that if is the name of a variable, not the if-keyword.
So you don´t need the verbatim in your case, because newline is not a keyword. Or in other words your code is equivalent to this:
Console.WriteLine("Hello with at0how are you?", @newline);
which is a valid (even though redundant) use of the verbatim.
For further information refer to the documentation about string-interpolation.
answered Aug 31 at 8:59
HimBromBeere
21.7k33156
edited Sep 4 at 6:41
answered Aug 31 at 8:59
HimBromBeere
21.7k33156
answered Aug 31 at 8:59
HimBromBeere
21.7k33156
answered Aug 31 at 8:59
HimBromBeere
21.7k33156
21.7k33156
1
$is not really a shortcut forString.Formatit basically returns aFormattableStringwhich in many ways differs fromString.Format
– Mateusz
Aug 31 at 9:09
@Mateusz Doesn´tString.Formatreturn anFormatableStringalso?
– HimBromBeere
Aug 31 at 9:10
Not quite the same,$can return astringalready processed,FormattableStringwhich then can be used to process it on how you want/need it to andIFormattablewhich is the only one that really relates toString.Formatmethod but it's not a shortcut, more like a long road to format.
– Mateusz
Aug 31 at 9:13
1
$"Hello myValue"is in fact also a shortcut tostring.Formatsince the compiler will only use theFormattableStringif the only target for the expression is aFormattableString. So the compiler will reformat this directly to astring.Formatcall.
– Lasse Vågsæther Karlsen
Aug 31 at 9:14
1
It is also worth to mention about interoperability between different languages. Keyword in one language is not necessarily the keyword in the second.
– Karol
Sep 1 at 12:11
 |Â
show 19 more comments
1
$is not really a shortcut forString.Formatit basically returns aFormattableStringwhich in many ways differs fromString.Format
– Mateusz
Aug 31 at 9:09
@Mateusz Doesn´tString.Formatreturn anFormatableStringalso?
– HimBromBeere
Aug 31 at 9:10
Not quite the same,$can return astringalready processed,FormattableStringwhich then can be used to process it on how you want/need it to andIFormattablewhich is the only one that really relates toString.Formatmethod but it's not a shortcut, more like a long road to format.
– Mateusz
Aug 31 at 9:13
1
$"Hello myValue"is in fact also a shortcut tostring.Formatsince the compiler will only use theFormattableStringif the only target for the expression is aFormattableString. So the compiler will reformat this directly to astring.Formatcall.
– Lasse Vågsæther Karlsen
Aug 31 at 9:14
1
It is also worth to mention about interoperability between different languages. Keyword in one language is not necessarily the keyword in the second.
– Karol
Sep 1 at 12:11
1
1
$ is not really a shortcut for String.Format it basically returns a FormattableString which in many ways differs from String.Format– Mateusz
Aug 31 at 9:09
$ is not really a shortcut for String.Format it basically returns a FormattableString which in many ways differs from String.Format– Mateusz
Aug 31 at 9:09
@Mateusz Doesn´t
String.Format return an FormatableString also?– HimBromBeere
Aug 31 at 9:10
@Mateusz Doesn´t
String.Format return an FormatableString also?– HimBromBeere
Aug 31 at 9:10
Not quite the same,
$ can return a string already processed, FormattableString which then can be used to process it on how you want/need it to and IFormattable which is the only one that really relates to String.Format method but it's not a shortcut, more like a long road to format.– Mateusz
Aug 31 at 9:13
Not quite the same,
$ can return a string already processed, FormattableString which then can be used to process it on how you want/need it to and IFormattable which is the only one that really relates to String.Format method but it's not a shortcut, more like a long road to format.– Mateusz
Aug 31 at 9:13
1
1
$"Hello myValue" is in fact also a shortcut to string.Format since the compiler will only use the FormattableString if the only target for the expression is a FormattableString. So the compiler will reformat this directly to a string.Format call.– Lasse Vågsæther Karlsen
Aug 31 at 9:14
$"Hello myValue" is in fact also a shortcut to string.Format since the compiler will only use the FormattableString if the only target for the expression is a FormattableString. So the compiler will reformat this directly to a string.Format call.– Lasse Vågsæther Karlsen
Aug 31 at 9:14
1
1
It is also worth to mention about interoperability between different languages. Keyword in one language is not necessarily the keyword in the second.
– Karol
Sep 1 at 12:11
It is also worth to mention about interoperability between different languages. Keyword in one language is not necessarily the keyword in the second.
– Karol
Sep 1 at 12:11
 |Â
show 19 more comments
up vote
13
down vote
It's a redundant verbatim prefix. From the C# specification:
The prefix "@" enables the use of keywords as identifiers, which is useful when interfacing with other programming languages. The character @ is not actually part of the identifier, so the identifier might be seen in other languages as a normal identifier, without the prefix. An identifier with an @ prefix is called a verbatim identifier. Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style.
A use case would be if you would want to write a function like this:
private void print(string @string) => Console.WriteLine(@string);
Normally you would not be able to name an identifier string because it is a reserved keyword. The @ prefix enables you to do so.
edited Aug 31 at 13:54
Peter Mortensen
12.9k1983111
answered Aug 31 at 9:01
ChristianMurschall
907315
4
Important part is "The character @ is not actually part of the identifier" because that explains why it compiles even if the variable doesn't have it.
– Tim Schmelter
Aug 31 at 9:08
4
Another part that I find important is "Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style." So@newlineis tolerated but misleading/confusing.
– Jeppe Stig Nielsen
Aug 31 at 9:40
I note that your example does not match the text you've quoted from the specification, and that this is a very poor use case. The purpose of this feature is not to allow you to make a formal parameter called@stringbecause that would be a bizarre thing to do. The purpose of the feature is to allow you to, say, extend a third-party class written in a non-C# language that has a virtual member calledstring. You need to be able to sayclass D : ThirdParty public override void @string() .... That would be a by-design use case.
– Eric Lippert
Aug 31 at 21:13
add a comment |Â
up vote
13
down vote
It's a redundant verbatim prefix. From the C# specification:
The prefix "@" enables the use of keywords as identifiers, which is useful when interfacing with other programming languages. The character @ is not actually part of the identifier, so the identifier might be seen in other languages as a normal identifier, without the prefix. An identifier with an @ prefix is called a verbatim identifier. Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style.
A use case would be if you would want to write a function like this:
private void print(string @string) => Console.WriteLine(@string);
Normally you would not be able to name an identifier string because it is a reserved keyword. The @ prefix enables you to do so.
edited Aug 31 at 13:54
Peter Mortensen
12.9k1983111
answered Aug 31 at 9:01
ChristianMurschall
907315
4
Important part is "The character @ is not actually part of the identifier" because that explains why it compiles even if the variable doesn't have it.
– Tim Schmelter
Aug 31 at 9:08
4
Another part that I find important is "Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style." So@newlineis tolerated but misleading/confusing.
– Jeppe Stig Nielsen
Aug 31 at 9:40
I note that your example does not match the text you've quoted from the specification, and that this is a very poor use case. The purpose of this feature is not to allow you to make a formal parameter called@stringbecause that would be a bizarre thing to do. The purpose of the feature is to allow you to, say, extend a third-party class written in a non-C# language that has a virtual member calledstring. You need to be able to sayclass D : ThirdParty public override void @string() .... That would be a by-design use case.
– Eric Lippert
Aug 31 at 21:13
add a comment |Â
up vote
13
down vote
up vote
13
down vote
It's a redundant verbatim prefix. From the C# specification:
The prefix "@" enables the use of keywords as identifiers, which is useful when interfacing with other programming languages. The character @ is not actually part of the identifier, so the identifier might be seen in other languages as a normal identifier, without the prefix. An identifier with an @ prefix is called a verbatim identifier. Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style.
A use case would be if you would want to write a function like this:
private void print(string @string) => Console.WriteLine(@string);
Normally you would not be able to name an identifier string because it is a reserved keyword. The @ prefix enables you to do so.
edited Aug 31 at 13:54
Peter Mortensen
12.9k1983111
answered Aug 31 at 9:01
ChristianMurschall
907315
It's a redundant verbatim prefix. From the C# specification:
The prefix "@" enables the use of keywords as identifiers, which is useful when interfacing with other programming languages. The character @ is not actually part of the identifier, so the identifier might be seen in other languages as a normal identifier, without the prefix. An identifier with an @ prefix is called a verbatim identifier. Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style.
A use case would be if you would want to write a function like this:
private void print(string @string) => Console.WriteLine(@string);
Normally you would not be able to name an identifier string because it is a reserved keyword. The @ prefix enables you to do so.
edited Aug 31 at 13:54
Peter Mortensen
12.9k1983111
answered Aug 31 at 9:01
ChristianMurschall
907315
edited Aug 31 at 13:54
Peter Mortensen
12.9k1983111
edited Aug 31 at 13:54
Peter Mortensen
12.9k1983111
edited Aug 31 at 13:54
Peter Mortensen
12.9k1983111
12.9k1983111
answered Aug 31 at 9:01
ChristianMurschall
907315
answered Aug 31 at 9:01
ChristianMurschall
907315
answered Aug 31 at 9:01
ChristianMurschall
907315
907315
4
Important part is "The character @ is not actually part of the identifier" because that explains why it compiles even if the variable doesn't have it.
– Tim Schmelter
Aug 31 at 9:08
4
Another part that I find important is "Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style." So@newlineis tolerated but misleading/confusing.
– Jeppe Stig Nielsen
Aug 31 at 9:40
I note that your example does not match the text you've quoted from the specification, and that this is a very poor use case. The purpose of this feature is not to allow you to make a formal parameter called@stringbecause that would be a bizarre thing to do. The purpose of the feature is to allow you to, say, extend a third-party class written in a non-C# language that has a virtual member calledstring. You need to be able to sayclass D : ThirdParty public override void @string() .... That would be a by-design use case.
– Eric Lippert
Aug 31 at 21:13
add a comment |Â
4
Important part is "The character @ is not actually part of the identifier" because that explains why it compiles even if the variable doesn't have it.
– Tim Schmelter
Aug 31 at 9:08
4
Another part that I find important is "Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style." So@newlineis tolerated but misleading/confusing.
– Jeppe Stig Nielsen
Aug 31 at 9:40
I note that your example does not match the text you've quoted from the specification, and that this is a very poor use case. The purpose of this feature is not to allow you to make a formal parameter called@stringbecause that would be a bizarre thing to do. The purpose of the feature is to allow you to, say, extend a third-party class written in a non-C# language that has a virtual member calledstring. You need to be able to sayclass D : ThirdParty public override void @string() .... That would be a by-design use case.
– Eric Lippert
Aug 31 at 21:13
4
4
Important part is "The character @ is not actually part of the identifier" because that explains why it compiles even if the variable doesn't have it.
– Tim Schmelter
Aug 31 at 9:08
Important part is "The character @ is not actually part of the identifier" because that explains why it compiles even if the variable doesn't have it.
– Tim Schmelter
Aug 31 at 9:08
4
4
Another part that I find important is "Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style." So
@newline is tolerated but misleading/confusing.– Jeppe Stig Nielsen
Aug 31 at 9:40
Another part that I find important is "Use of the @ prefix for identifiers that are not keywords is permitted, but strongly discouraged as a matter of style." So
@newline is tolerated but misleading/confusing.– Jeppe Stig Nielsen
Aug 31 at 9:40
I note that your example does not match the text you've quoted from the specification, and that this is a very poor use case. The purpose of this feature is not to allow you to make a formal parameter called
@string because that would be a bizarre thing to do. The purpose of the feature is to allow you to, say, extend a third-party class written in a non-C# language that has a virtual member called string. You need to be able to say class D : ThirdParty public override void @string() ... . That would be a by-design use case.– Eric Lippert
Aug 31 at 21:13
I note that your example does not match the text you've quoted from the specification, and that this is a very poor use case. The purpose of this feature is not to allow you to make a formal parameter called
@string because that would be a bizarre thing to do. The purpose of the feature is to allow you to, say, extend a third-party class written in a non-C# language that has a virtual member called string. You need to be able to say class D : ThirdParty public override void @string() ... . That would be a by-design use case.– Eric Lippert
Aug 31 at 21:13
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1
Possible duplicate: stackoverflow.com/questions/6134547/…
– Keyur Ramoliya
Aug 31 at 8:59
5
This one is related
– Mong Zhu
Aug 31 at 9:00
7
@KeyurRamoliya: It's definitely not a duplicate of that. That's about verbatim string literals. This isn't one of those. It's using
@with an identifier, which is typically used with keywords, e.g.@thisas the name of the first parameter in an extension method.– Jon Skeet
Aug 31 at 9:00
@KeyurRamoliya I don't think that's a correct duplicate. HimBromBeere's answer is correct.
– Sweeper
Aug 31 at 9:01
Reference for verbatim string here.
– Tetsuya Yamamoto
Aug 31 at 9:01