1- How do I do in D the equivalent of the following C++ macro?

#define OUT_VAL(val) (count << #val << " = " << val << endl)

In particular the #val above to the actual macro argument as a string?

2- Yesterday I was experimenting with something and I wrote something like the following:

struct MyType {
  ...
}

void doSomeWork(ref MyType o) {
   ...
}

auto t = MyType(...);

t.doSomeWork(); // <-- failed to compile.

Why did the above UFCS call fail to compile? I had to do doSomeWork(t) instead.

Thank you so much!

On Wed, Jan 02, 2019 at 05:38:41PM +0000, IM via Digitalmars-d-learn wrote:
> 1- How do I do in D the equivalent of the following C++ macro?
> 
> #define OUT_VAL(val) (count << #val << " = " << val << endl)
> 
> In particular the #val above to the actual macro argument as a string?
[...]

Try something along these lines:

	import std.stdio;
	void OUT_VAL(alias val)() {
		writefln("%s = %s", __traits(identifier, val), val);
	}
	void main() {
		int i = 123;
		string s = "abc";
		OUT_VAL!i;
		OUT_VAL!s;
	}


T

-- 
The easy way is the wrong way, and the hard way is the stupid way. Pick one.

On 1/2/19 12:38 PM, IM wrote:

> 2- Yesterday I was experimenting with something and I wrote something like the following:
> 
> struct MyType {
>    ...
> }
> 
> void doSomeWork(ref MyType o) {
>     ...
> }
> 
> auto t = MyType(...);
> 
> t.doSomeWork(); // <-- failed to compile.
> 
> Why did the above UFCS call fail to compile? I had to do doSomeWork(t) instead.

With those ... I have to guess.

There are 2 possibilities.

Possibility 1: there is a method named 'doSomeWork' which takes at least one parameter. This overrides the UFCS function (member functions always win over UFCS).

Possibility 2: All this is actually inside a function or unittest. Nested functions cannot participate in UFCS.

Of course, these are guesses. But given the very scant code above, I'm not sure I could offer any other suggestions. If neither of those is the case, I'd need a working example.

-Steve

On Wednesday, 2 January 2019 at 21:56:03 UTC, Steven Schveighoffer wrote:
> On 1/2/19 12:38 PM, IM wrote:
>
>> [...]
>
> With those ... I have to guess.
>
> There are 2 possibilities.
>
> Possibility 1: there is a method named 'doSomeWork' which takes at least one parameter. This overrides the UFCS function (member functions always win over UFCS).
>
> Possibility 2: All this is actually inside a function or unittest. Nested functions cannot participate in UFCS.
>

Perfect, this was it. Thank you so much. doSomeWork() was nested inside a unittest{} block. I didn't know UFCS won't work in this case.

> Of course, these are guesses. But given the very scant code above, I'm not sure I could offer any other suggestions. If neither of those is the case, I'd need a working example.
>
> -Steve

On Wednesday, 2 January 2019 at 17:49:52 UTC, H. S. Teoh wrote:
> On Wed, Jan 02, 2019 at 05:38:41PM +0000, IM via Digitalmars-d-learn wrote:
>> 1- How do I do in D the equivalent of the following C++ macro?
>> 
>> #define OUT_VAL(val) (count << #val << " = " << val << endl)
>> 
>> In particular the #val above to the actual macro argument as a string?
> [...]
>
> Try something along these lines:
>
> 	import std.stdio;
> 	void OUT_VAL(alias val)() {
> 		writefln("%s = %s", __traits(identifier, val), val);
> 	}
> 	void main() {
> 		int i = 123;
> 		string s = "abc";
> 		OUT_VAL!i;
> 		OUT_VAL!s;
> 	}
>
>
> T

Thank you so much. Will give this a try.