Template method and type resolution of return type

[matovitch via Digitalmars-d-learn]

On Saturday, 19 April 2014 at 17:49:54 UTC, bearophile wrote:
> matovitch:
>
>> struct Test
>> {
>> 	immutable (ubyte)[] data;
>>
>> 	T get(T)()
>> 	{
>> 		return *(cast(T*)(&(data[0])));
>> 	}
>
> It's better to return const/immutable data. Otherwise the 
> program gives undefined results. In alternative use mutable 
> ubytes for data.
>
> Also &data[0] is probably data.ptr.

I did'nt know that one.

>
>
>> This won't compile :
>>
>> import std.stdio;
>>
>> void main()
>> {
>> 	Test t;
>> 	t.data = [152, 32, 64, 28, 95];
>> 	float b = t.get;
>> 	writefln("%s", b);
>
> D doesn't perform inference on the return type.

I see. But why ?

It's seems it exits a workaround overloading cast operators in 
c++ :
     
http://programmaticallyspeaking.blogspot.se/2012/09/infer-return-type-for-templated.html

However I think it would only work with opImplicitCast in D. The 
code given in vibe.d doc could became :

void manipulateJson(Json j)
{
	j = Json.emptyObject;
	j.name = "Example";
	j.id = 1;

	// retrieving the values is done using get()
	assert(j["name"] == "Example");
	assert(j["id"] == 1);

	// print out as JSON: {"name": "Example", "id": 1}
	writefln("JSON: %s", j.toString());
}


ps : Thank you for all your great examples on Rosetta code (or 
the last one about the rubik's cube).