How to get a function name (string) @ compile time

[Andrew Pennebaker]

On Monday, 3 November 2008 at 12:29:16 UTC, Simen Kjaeraas wrote:
> On Mon, 03 Nov 2008 12:33:05 +0100, Denis Koroskin 
> <2korden at gmail.com> wrote:
>
>> On Mon, 03 Nov 2008 04:11:20 +0300, Daniel Ribeiro Maciel 
>> <daniel.maciel at gmail.com> wrote:
>>
>>> Denis Koroskin Wrote:
>>>
>>>> On Mon, 03 Nov 2008 01:59:56 +0300, Daniel Ribeiro Maciel
>>>> <daniel.maciel at gmail.com> wrote:
>>>>
>>>> > How do we get a function name (string) @ compile time?
>>>> >
>>>> > I need to do stuff like (in C)
>>>> >
>>>> > #include <stdio.h>
>>>> >
>>>> > #define HELLO( func ) \
>>>> >   printf( "calling " #func "\n" ); \
>>>> >   func();
>>>> >
>>>> > void foo()
>>>> > {
>>>> > 	printf( "@foo" );
>>>> > }
>>>> >
>>>> > int main()
>>>> > {
>>>> > 	HELLO( foo );
>>>> > 	printf( "\n" );
>>>> > }
>>>> >
>>>> > The output is:
>>>> > calling foo
>>>> > @foo
>>>> >
>>>> > Thanks in advance,
>>>> > Daniel
>>>> >
>>>>
>>>> Just in case you know little D here is the source code, 
>>>> explanation and
>>>> comparison to C++:
>>>>
>>>> import std.stdio; // this is used to import writefln() - a 
>>>> function
>>>> similar to printf (but typesafe)
>>>>
>>>> // this is a template function that takes almost anything 
>>>> (close to C++
>>>> templates and C macros)
>>>> void print(alias functionName)()
>>>> {
>>>>      // stringof is used to take a string representation of 
>>>> the identifier
>>>>      writefln("Calling ", functionName.stringof);
>>>>
>>>>      // let's invoke it! This will succeed if functionName 
>>>> is a function,
>>>> pointer to function,
>>>>      // delegate or an object that have overloaded opCall() 
>>>> (similar to C++
>>>> operator())
>>>>      functionName();
>>>> }
>>>>
>>>> void foo()
>>>> {
>>>>      writefln("@foo"); // same as printf("@foo);
>>>> }
>>>>
>>>> void main()
>>>> {
>>>>      // foo is a global (free) function. it is passed to the 
>>>> template
>>>> function.
>>>>      // In C++ you would do print<foo>(); (but C++ doesn't 
>>>> support
>>>> specializing
>>>>      // templates with functions nor does it have .stringof)
>>>>      print!(foo);
>>>> }
>>>
>>> Thanx a lot! It worked for some functions.
>>>
>>> I found a problem though. If we change foo to:
>>>
>>> void foo( double i )
>>> {
>>>      writefln("@foo ", i );
>>> }
>>>
>>> the compiler yields an error:
>>>
>>> test.d(30): function app.sandbox.main.foo (double i) does not 
>>> match parameter types ()
>>> test.d(30): Error: expected 1 arguments, not 0]
>>>
>>> line 30 is this:      writefln("Calling ", 
>>> functionName.stringof);
>>>
>>> Is this supposed to be a bug?
>>>
>>> Best regards,
>>> Daniel
>>>
>>
>> Yes, it is. For some reason it tries to evaluate function 
>> first and *then* take the stringof property (that is of the 
>> returned value), i.e. it rewrites it as 
>> "functionName().stringof". I have written about this bug 4 
>> months ago ("Omittable parens is an evil" thread) but it is 
>> not fixed yet.
>
> That's not the only error here. Your template function also 
> calls
> foo with no arguments on  the line below that bug. Fixing that 
> would
> probably include the ParameterTypeTuple and ReturnType 
> templates.

Er, when I try to use either foo.stringof, or __trait(identifier, 
foo), I always get that binding name, rather than the original 
function name, sad panda.

I can only print out the current variable name, but I want to 
print the name of the function declaration, no matter how deeply 
I pass that first function pointer into different calls :/