Get name of enum val at compile-time?

2012-01-15 Thread Nick Sabalausky 
Is there a way to get the name of an enum value at compile-time?

For instance:

import std.stdio;
enum Foo { hello }
void main()
{
writeln(Foo.hello);
}

That prints hello. But what I need is to get hello into a string at 
compile-time.

Of course, I could just manually write a ctfe-able fooToString(), or 
implement something like std.typecons.defineEnum (which appears to be 
deprecated now). But I'm wondering if I'm overlooking a better solution.

Re: Get name of enum val at compile-time?

2012-01-15 Thread Jonathan M Davis 
On Sunday, January 15, 2012 03:53:09 Nick Sabalausky wrote:
 Is there a way to get the name of an enum value at compile-time?
 
 For instance:
 
 import std.stdio;
 enum Foo { hello }
 void main()
 {
 writeln(Foo.hello);
 }
 
 That prints hello. But what I need is to get hello into a string at
 compile-time.
 
 Of course, I could just manually write a ctfe-able fooToString(), or
 implement something like std.typecons.defineEnum (which appears to be
 deprecated now). But I'm wondering if I'm overlooking a better solution.

to!string(Foo.hello)

- Jonathan M Davis

Re: Get name of enum val at compile-time?

2012-01-15 Thread Nick Sabalausky 
Jonathan M Davis jmdavisp...@gmx.com wrote in message 
news:mailman.388.1326617938.16222.digitalmars-d-le...@puremagic.com...
 On Sunday, January 15, 2012 03:53:09 Nick Sabalausky wrote:
 Is there a way to get the name of an enum value at compile-time?

 For instance:

 import std.stdio;
 enum Foo { hello }
 void main()
 {
 writeln(Foo.hello);
 }

 That prints hello. But what I need is to get hello into a string at
 compile-time.

 Of course, I could just manually write a ctfe-able fooToString(), or
 implement something like std.typecons.defineEnum (which appears to be
 deprecated now). But I'm wondering if I'm overlooking a better solution.

 to!string(Foo.hello)


Nope. That was the first thing I tried.

With 2.057:

type testCTEnumToString.d
import std.conv;
enum Foo { hello }
enum x = to!string();

dmd testCTEnumToString.d -c
phobos\std\conv.d(237): Error: template std.conv.toImpl(T,S) if 
(isImplicitlyConvertible!(S,T)) does not match any function template 
declaration
phobos\std\conv.d(237): Error: template std.conv.toImpl(T,S) if 
(isImplicitlyConvertible!(S,T)) cannot deduce template function from 
argument types !(string)()
phobos\std\conv.d(237): Error: template instance toImpl!(string) errors 
instantiating template
testCTEnumToString.d(3):called from here: to()

Doesn't work at runtime, either:

type testRTEnumToString.d
import std.conv;
enum Foo { hello }
void main()
{
auto x = to!string();
}

dmd testRTEnumToString.d -c
phobos\std\conv.d(237): Error: template std.conv.toImpl(T,S) if 
(isImplicitlyConvertible!(S,T)) does not match any function template 
declaration
phobos\std\conv.d(237): Error: template std.conv.toImpl(T,S) if 
(isImplicitlyConvertible!(S,T)) cannot deduce template function from 
argument types !(string)()
phobos\std\conv.d(237): Error: template instance toImpl!(string) errors 
instantiating template
testRTEnumToString.d(5): Error: template instance std.conv.to!(string).to!() 
error instantiating

Re: Get name of enum val at compile-time?

2012-01-15 Thread Nick Sabalausky 
Timon Gehr timon.g...@gmx.ch wrote in message 
news:jevefv$2je6$1...@digitalmars.com...
 On 01/15/2012 09:34 PM, Nick Sabalausky wrote:
 import std.conv;
 enum Foo { hello }
 enum x = to!string();


 enum x = to!string(Foo.hello);

Goddamnnit, what the fuck is wrong with me? Yes that works :)

Re: Get name of enum val at compile-time?

2012-01-15 Thread Timon Gehr 

On 01/15/2012 10:02 PM, Nick Sabalausky wrote:

Timon Gehrtimon.g...@gmx.ch  wrote in message
news:jevefv$2je6$1...@digitalmars.com...

On 01/15/2012 09:34 PM, Nick Sabalausky wrote:

import std.conv;
enum Foo { hello }
enum x = to!string();



enum x = to!string(Foo.hello);


Goddamnnit, what the fuck is wrong with me? Yes that works :)




I suspect a better error message would have prevented this.
DMD still has some potential of improvement in that area. =)

Re: Get name of enum val at compile-time?

2012-01-15 Thread Philippe Sigaud 
On Sun, Jan 15, 2012 at 22:19, Timon Gehr timon.g...@gmx.ch wrote:

Nick:
 Goddamnnit, what the fuck is wrong with me? Yes that works :)

 I suspect a better error message would have prevented this.
 DMD still has some potential of improvement in that area. =)

In that case, to!(Origin, Target) could be extended to deal with
to!(Origin, empty there).
It's been a long time since I last looked at std.conv.to, but maybe:

template to(T)
{
T to(A...)(A args)
{
static if (A.length)
return toImpl!T(args);
else
static assert(false, Trying to use to!(~T.stringof~)
with no argument. What were you trying to do?);
}
}

Re: Get name of enum val at compile-time?

2012-01-15 Thread Peter Alexander 

On 15/01/12 10:29 PM, Philippe Sigaud wrote:

On Sun, Jan 15, 2012 at 22:19, Timon Gehrtimon.g...@gmx.ch  wrote:

Nick:

Goddamnnit, what the fuck is wrong with me? Yes that works :)


I suspect a better error message would have prevented this.
DMD still has some potential of improvement in that area. =)


In that case, to!(Origin, Target) could be extended to deal with
to!(Origin,empty there).
It's been a long time since I last looked at std.conv.to, but maybe:

template to(T)
{
 T to(A...)(A args)
 {
 static if (A.length)
 return toImpl!T(args);
 else
 static assert(false, Trying to use to!(~T.stringof~)
with no argument. What were you trying to do?);
 }
}


The compiler should be able to give you a better error message. It 
shouldn't be the responsibility of the programmer to provide sensible 
error messages when you call a function with the wrong number of arguments.