In C, you can use a macro to get the source text of an expression as a string. For example

#include <stdio.h>
#define PRINT_INT(x) printf(#x " = %d\n", x)

int main(){
    // prints "3 = 3"
    PRINT_INT(3);
    int x = 4;
    // prints "x = 4"
    PRINT_INT(x);
#define FOO 5
    // prints "FOO = 5"
    PRINT_INT(FOO);
#define BAR FOO
    // prints "BAR = 5"
    PRINT_INT(BAR);
    return 0;
}

Is there a feature of D that allows you to achieve a similar goal? I’ve used this in the past for logging for example.

On Thursday, 17 December 2020 at 19:45:38 UTC, Dave P. wrote:
> In C, you can use a macro to get the source text of an expression as a string. For example
>
> #include <stdio.h>
> #define PRINT_INT(x) printf(#x " = %d\n", x)
>
> int main(){
>     // prints "3 = 3"
>     PRINT_INT(3);
>     int x = 4;
>     // prints "x = 4"
>     PRINT_INT(x);
> #define FOO 5
>     // prints "FOO = 5"
>     PRINT_INT(FOO);
> #define BAR FOO
>     // prints "BAR = 5"
>     PRINT_INT(BAR);
>     return 0;
> }
>
> Is there a feature of D that allows you to achieve a similar goal? I’ve used this in the past for logging for example.

Something like that?

import  std.stdio;

void print_int(alias n)()
{
    writeln(n.stringof~"=", n);
}

void main()
{
    int x = 42;
    print_int!(x);
    print_int!(7);
}

On Thursday, 17 December 2020 at 19:45:38 UTC, Dave P. wrote:
> In C, you can use a macro to get the source text of an expression as a string. For example
>
> #include <stdio.h>
> #define PRINT_INT(x) printf(#x " = %d\n", x)
>
> int main(){
>     // prints "3 = 3"
>     PRINT_INT(3);
>     int x = 4;
>     // prints "x = 4"
>     PRINT_INT(x);
> #define FOO 5
>     // prints "FOO = 5"
>     PRINT_INT(FOO);
> #define BAR FOO
>     // prints "BAR = 5"
>     PRINT_INT(BAR);
>     return 0;
> }
>
> Is there a feature of D that allows you to achieve a similar goal? I’ve used this in the past for logging for example.

https://code.dlang.org/packages/jdiutil

On Thursday, 17 December 2020 at 21:24:40 UTC, FreeSlave wrote:
> On Thursday, 17 December 2020 at 19:45:38 UTC, Dave P. wrote:
>> [...]
>
> Something like that?
>
> import  std.stdio;
>
> void print_int(alias n)()
> {
>     writeln(n.stringof~"=", n);
> }
>
> void main()
> {
>     int x = 42;
>     print_int!(x);
>     print_int!(7);
> }

Very cool! Where can I read about what an alias as a template parameter does?

On Thursday, 17 December 2020 at 21:40:09 UTC, Dave P. wrote:

> Very cool! Where can I read about what an alias as a template parameter does?

https://dlang.org/spec/template.html#aliasparameters

https://github.com/PhilippeSigaud/D-templates-tutorial