Won't compile for obvious reasons:

struct Bar { }
struct Foo
{
    this(Bar bar, int line = __LINE__)
    {
        pragma(msg, "Warning: Constructing Foo with Bar incurs
precision loss. Line: " ~ line);
    }
}

void main()
{
    auto foo = Foo(Bar());
}

That's just an example, but I want to issue a compile-time warning when a specific ctor is called because it might incur precision loss. I want to give the user the line number of the call, but I can't call to!string since it's not ctfe-able, so do I have any other options?

On 2011-09-21 02:18, Andrej Mitrovic wrote:
> Won't compile for obvious reasons:
>
> struct Bar { }
> struct Foo
> {
>      this(Bar bar, int line = __LINE__)
>      {
>          pragma(msg, "Warning: Constructing Foo with Bar incurs
> precision loss. Line: " ~ line);
>      }
> }
>
> void main()
> {
>      auto foo = Foo(Bar());
> }
>
> That's just an example, but I want to issue a compile-time warning
> when a specific ctor is called because it might incur precision loss.
> I want to give the user the line number of the call, but I can't call
> to!string since it's not ctfe-able, so do I have any other options?

Have a look at: http://d-programming-language.org/templates-revisited.html

Search for "Template Metaprogramming With Strings".

-- 
/Jacob Carlborg

On 9/21/11, Jacob Carlborg <doob@me.com> wrote:
> Have a look at: http://d-programming-language.org/templates-revisited.html

Right, but as I've said conv.to works at compile-time so that's unnecessary. Maybe adding a note there about this would be nice, so people don't spend time reimplementing common compile-time conversions that conv.to can already do.

On 2011-09-21 13:59, Andrej Mitrovic wrote:
> On 9/21/11, Jacob Carlborg<doob@me.com>  wrote:
>> Have a look at: http://d-programming-language.org/templates-revisited.html
>
> Right, but as I've said conv.to works at compile-time so that's
> unnecessary. Maybe adding a note there about this would be nice, so
> people don't spend time reimplementing common compile-time conversions
> that conv.to can already do.

Oh, I missed one of your posts, sorry.

-- 
/Jacob Carlborg