Named arguments

[Andrey]

On Tuesday, 24 October 2017 at 20:36:00 UTC, H. S. Teoh wrote:
> On Tue, Oct 24, 2017 at 01:22:41PM -0600, Jonathan M Davis via 
> Digitalmars-d wrote: [...]
>> Personally, I don't want them in D. If you have enough 
>> arguments that it matters, then the function probably has too 
>> many parameters or too many similar parameters.
>
> If a function has too many parameters, or only a small subset 
> of parameters need to be something other than some default 
> value, or the set of parameters may change frequently, then my 
> default approach is to abstract the parameters into a struct:
>
> 	struct OutputArgs {
> 		string filename;
> 		int width = 300;
> 		int height = 300;
> 		string fontDir = "/usr/share/local/fonts/arial.ttf";
> 		int fontSize = 12;
> 		Color background = Color.black;
> 		Color foreground = Color.white;
> 		bool antiAlias = true;
> 	}
>
> 	void generateOutput(OutputArgs args) { ... }
>
> 	void main() {
> 		// Setup function arguments.
> 		// N.B.: only .filename needs to be explicitly set.
> 		OutputArgs args;
> 		args.filename = "/tmp/output.png";
>
> 		// Call function with mostly default arguments.
> 		generateOutput(args);
> 	}
>
> This approach means that if you ever need to add more 
> parameters to OutputArgs, as long as the default value is 
> compatible with previous behaviour, you won't have to change 
> existing code. Also, the caller can set the arguments in any 
> order without needing to memorize which parameter is in which 
> position.
> ...

good alternative, I already forgot about the power of structs 
after Java.