Function meta information

[Denis Koroskin]

On Fri, 25 Dec 2009 17:19:42 +0300, Eldar Insafutdinov  
<e.insafutdinov at gmail.com> wrote:

> Currently we have ParameterTypeTuple for extracting type list of  
> function arguments. This is not enough. There should be a clean way to  
> extract storage classes and default arguments if there are any. Any  
> thoughts?

I guess you must parse string representation of the function to get  
everythig you need as of now.
I know someone already did this and posted his code on dsource.org, but I  
can't tell where exactly I saw it out of my head.

If you decide to make your own implementation, here is a start:

struct Foo
{
}

void bar(ref Foo foo, int i = 42)
{
}

void Inspect(T)(T t)
{
	pragma(msg, T.stringof);
}

void main()
{
	Inspect(&bar);
}

Output:
void function(ref Foo foo, int i = 42)

Note that function properties are *extremely* bugged ATM - compiler  
mistakenly thinks that "bar" and typeof(bar)", or "bar.stringof" and  
"bar().stringof" are interchangeable (omissible parens hell). For example:

template ToString(alias func)
{
	pragma(msg, typeof(func).stringof);
	enum ToString = typeof(func).stringof;
}

void main()
{
	enum s = ToString!(bar);
}

results in the following output:

test.d(11): Error: expected 2 function arguments, not 0
(void(ref Foo foo, int i = 42))() // TADAM!
test.d(12): Error: expected 2 function arguments, not 0
test.d(17): Error: template instance test.ToString!(bar) error  
instantiating

This one will hopefully resolved once @property feature gets implemented  
and omissible parens will go away.