www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.learn - template with enum parameter doesn't compile

reply Sjoerd Nijboer <dlang sjoerdnijboer.com> writes:
So the following code doesn't compile for some reason, and I 
can't figure out why.

enum MyEnum { A, B, C }

class MyClass(MyEnum myEnum)
{
     /*...*/
}

int main()
{
	MyClass!MyEnum.A a;
}

The error:  Error: template instance `MyClass!(MyEnum)` does not 
match template declaration `MyClass(MyEnum myEnum)`
pops up, no matter what I do.
I'm quite puzzled actually
Apr 05
next sibling parent reply lithium iodate <whatdoiknow doesntexist.net> writes:
On Friday, 5 April 2019 at 14:47:42 UTC, Sjoerd Nijboer wrote:
 So the following code doesn't compile for some reason, and I 
 can't figure out why.
 The error:  Error: template instance `MyClass!(MyEnum)` does 
 not match template declaration `MyClass(MyEnum myEnum)`
 pops up, no matter what I do.
 I'm quite puzzled actually
You are just having a little issue with operator precedence there. Your code attempts to get the member `A` from `MyClass!MyEnum`, if you add braces around it, it'll work just fine `MyClass!(MyEnum.A)`.
Apr 05
parent Sjoerd Nijboer <dlang sjoerdnijboer.com> writes:
On Friday, 5 April 2019 at 14:52:05 UTC, lithium iodate wrote:
 You are just having a little issue with operator precedence 
 there. Your code attempts to get the member `A` from 
 `MyClass!MyEnum`, if you add braces around it, it'll work just 
 fine `MyClass!(MyEnum.A)`.
That's really funny acutally. It works. Thank you!
Apr 05
prev sibling parent Nicholas Wilson <iamthewilsonator hotmail.com> writes:
On Friday, 5 April 2019 at 14:47:42 UTC, Sjoerd Nijboer wrote:
 So the following code doesn't compile for some reason, and I 
 can't figure out why.

 enum MyEnum { A, B, C }

 class MyClass(MyEnum myEnum)
 {
     /*...*/
 }

 int main()
 {
 	MyClass!MyEnum.A a;
 }

 The error:  Error: template instance `MyClass!(MyEnum)` does 
 not match template declaration `MyClass(MyEnum myEnum)`
 pops up, no matter what I do.
You wrote:
 MyClass!MyEnum.A a;
Which is equivalent to
 MyClass!(MyEnum).A a;
What you want is MyClass!(MyEnum.A) a;
Apr 05