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digitalmars.D.learn - Can I infer the type from this?

reply Dr.No <jckj33 gmail.com> writes:
I'd like to pass a symbol as paramater (class static member0 and 
at same time get the type of this, something like this:

template myTemp(alias s)
{
	enum myTemp = templateFunction!(??)(s.stringof);
}

the templateFunction has this signature:

int templateFunction(T)(string targetMembername)

but I don't how to get the type name from the give symbol name in 
myTemp. Can I make this work?
May 19 2018
parent reply Alex <sascha.orlov gmail.com> writes:
On Sunday, 20 May 2018 at 01:41:03 UTC, Dr.No wrote:

 I'd like to pass a symbol as paramater (class static member0 
 and at same time get the type of this, something like this:

 template myTemp(alias s)
 {
 	enum myTemp = templateFunction!(??)(s.stringof);
 }

 the templateFunction has this signature:

 int templateFunction(T)(string targetMembername)

 but I don't how to get the type name from the give symbol name 
 in myTemp. Can I make this work?


Something like this?

´´´
import std.stdio;

void main()
{
	size_t s;
	auto res = myTemp!s;
}


template myTemp(alias s)
{
	enum myTemp = templateFunction!(typeof(s))(s.stringof);
}


int templateFunction(T)(string targetMembername)
{
	static assert(is(T == size_t));
	assert(targetMembername == "s");
	return 42;
}
´´´
May 19 2018
parent reply Dr.No <jckj33 gmail.com> writes:
On Sunday, 20 May 2018 at 02:01:20 UTC, Alex wrote:

 On Sunday, 20 May 2018 at 01:41:03 UTC, Dr.No wrote:

 I'd like to pass a symbol as paramater (class static member0 
 and at same time get the type of this, something like this:

 template myTemp(alias s)
 {
 	enum myTemp = templateFunction!(??)(s.stringof);
 }

 the templateFunction has this signature:

 int templateFunction(T)(string targetMembername)

 but I don't how to get the type name from the give symbol name 
 in myTemp. Can I make this work?


 Something like this?

 ´´´
 import std.stdio;

 void main()
 {
 	size_t s;
 	auto res = myTemp!s;
 }


 template myTemp(alias s)
 {
 	enum myTemp = templateFunction!(typeof(s))(s.stringof);
 }


 int templateFunction(T)(string targetMembername)
 {
 	static assert(is(T == size_t));
 	assert(targetMembername == "s");
 	return 42;
 }
 ´´´


Oh, my bad: I totally forgot a crucial thing on question: I want 
this to work with a static member, for example, call myTemp like 
this myTemp!(C.a) I don't mind if I to pass the type as parameter 
somehow, like myTemp!(C, C.a) or myTemp!(C)(C.a) but I do need to 
pass a symbol as parameter, hence I'm using alias template 
parameter.
May 19 2018
parent Alex <sascha.orlov gmail.com> writes:
On Sunday, 20 May 2018 at 03:16:39 UTC, Dr.No wrote:

 Oh, my bad: I totally forgot a crucial thing on question: I 
 want this to work with a static member, for example, call 
 myTemp like this myTemp!(C.a) I don't mind if I to pass the 
 type as parameter somehow, like myTemp!(C, C.a) or 
 myTemp!(C)(C.a) but I do need to pass a symbol as parameter, 
 hence I'm using alias template parameter.


Still not sure, if I get you right...

´´´
import std.stdio;

void main() { auto res = myTemp!(C.s); }

class C { static size_t s; }

template myTemp(alias s) { enum myTemp = 
templateFunction!(typeof(s))(s.stringof); }

int templateFunction(T)(string targetMembername)
{
	static assert(is(T == size_t));
	assert(targetMembername == "s");
	return 42;
}
´´´

In general, I'm not sure, how you want to get a type of a general 
symbol (this is what templateFunction should do, isn't it?) as it 
could be a template or a value parameter for example.
However, I tried these cases, and typeof yields something 
reasonable then. In particular, it still did compile and yields 
something which could be checked against...
May 20 2018