• IM (17/17) Jan 02 2019 1- How do I do in D the equivalent of the following C++ macro?
• H. S. Teoh (16/21) Jan 02 2019 [...]
• IM (2/23) Jan 02 2019 Thank you so much. Will give this a try.
• Steven Schveighoffer (12/29) Jan 02 2019 With those ... I have to guess.
• IM (5/18) Jan 02 2019 Perfect, this was it. Thank you so much. doSomeWork() was nested

IM <3di gm.com> writes:

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!

"H. S. Teoh" <hsteoh quickfur.ath.cx> writes:

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.

IM <3di gm.com> writes:

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.

Steven Schveighoffer <schveiguy gmail.com> writes:

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

IM <3di gm.com> writes:

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