Re: Inspecting lambda parameters

[Meta via Digitalmars-d-learn]

On Saturday, 10 May 2014 at 10:56:57 UTC, Jacob Carlborg wrote:
I know that there are templates to inspect function parameters, 
like ParameterIdentifierTuple and ParameterTypeTuple. But these 
don't work for templated/untyped lambdas, they're apparently 
not callables. I don't expect ParameterTypeTuple to work, but 
it would be nice if ParameterIdentifierTuple and "arity" worked.

Here's an example for clarify:

void foo (alias func) ()
{
    alias Types = ParameterTypeTuple!(func);
}

void main ()
{
    foo!(x => x * 2);
}

Anyone know if this is fixable or if there's a workaround? I 
would like to avoid using hacks like .stringof. I know there's 
__parameters as well, but that doesn't work either.

Wasn't there recently a pull request to add TemplateArgsOf, or 
something like that. Also, if you know what type the lambda is 
going to be instantiated with, you can turn it into a function by 
doing:

void foo (alias func) ()
{
    alias Types = ParameterTypeTuple!(func!int);
}