• Adam S (20/20) Jan 04 2014 I've encountered an issue using the 'with' statement. Can anyone
• bearophile (5/8) Jan 04 2014 Perhaps because "test" is not a member variable name. It's a
• Adam S (16/36) Jan 04 2014 Most template member funs seems to work fine. The issue only
• bearophile (8/23) Jan 04 2014 with() was designed and created to access fields of structs in a

"Adam S" <adamschwalm gmail.com> writes:

I've encountered an issue using the 'with' statement. Can anyone 
explain why the following requires that I explicitly specify the 
variable name, even though it is within a 'with'?

class Foo {
     auto test(alias val)() if (is(typeof(val) == int)){}
     auto test(alias val)() if (!is(typeof(val) == int)){}
}

void main() {

     auto bar = new Foo;

     with (bar) {
         //test!2();        //fails to compile
         //test!"cats"();   //fails to compile
         bar.test!2();      //works
         bar.test!"cats"(); //works
     }
}

The commented out lines fail with:
     Error: need 'this' for 'test' of type 'pure nothrow  safe 
void()'

Thanks

"bearophile" <bearophileHUGS lycos.com> writes:

Adam S:

 I've encountered an issue using the 'with' statement. Can 
 anyone explain why the following requires that I explicitly 
 specify the variable name,

Perhaps because "test" is not a member variable name. It's a 
(templated) class method.

Bye,
bearophile

"Adam S" <adamschwalm gmail.com> writes:

On Saturday, 4 January 2014 at 20:56:41 UTC, Adam S wrote:
 I've encountered an issue using the 'with' statement. Can 
 anyone explain why the following requires that I explicitly 
 specify the variable name, even though it is within a 'with'?

 class Foo {
     auto test(alias val)() if (is(typeof(val) == int)){}
     auto test(alias val)() if (!is(typeof(val) == int)){}
 }

 void main() {

     auto bar = new Foo;

     with (bar) {
         //test!2();        //fails to compile
         //test!"cats"();   //fails to compile
         bar.test!2();      //works
         bar.test!"cats"(); //works
     }
 }

 The commented out lines fail with:
     Error: need 'this' for 'test' of type 'pure nothrow  safe 
 void()'

 Thanks

Most template member funs seems to work fine. The issue only 
seems to appear when the member function is overloaded. For 
example

class Foo {
     auto test(alias val)() if (is(typeof(val) == int)){}
     //auto test(alias val)() if (!is(typeof(val) == int)){}

}

void main() {
     auto bar = new Foo;

     with (bar) {
         test!2();      //works
     }
}

works fine until the overload of test is uncommented. Then the 
same error occurs.

"bearophile" <bearophileHUGS lycos.com> writes:

Adam S:

 Most template member funs seems to work fine. The issue only 
 seems to appear when the member function is overloaded. For 
 example

 class Foo {
     auto test(alias val)() if (is(typeof(val) == int)){}
     //auto test(alias val)() if (!is(typeof(val) == int)){}

 }

 void main() {
     auto bar = new Foo;

     with (bar) {
         test!2();      //works
     }
 }

 works fine until the overload of test is uncommented. Then the 
 same error occurs.

with() was designed and created to access fields of structs in a 
simpler way. In D also enum and class members are usable with 
with(). Your use case seems a corner case of a usage pattern that 
was not included. So perhaps you have to write an enhancement 
request.

Bye,
bearophile