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);
}

Re: Inspecting lambda parameters

[Jacob Carlborg via Digitalmars-d-learn]

On 2014-05-10 18:56, Meta wrote:


Wasn't there recently a pull request to add TemplateArgsOf, or something
like that.


There's this pull request [1] that adds a couple of new traits that 
might help.



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);
}


Unfortunately I don't know the types it's going to be instantiated with. 
That's part of the introspecting to figure out.


[1] https://github.com/D-Programming-Language/dmd/pull/3515

--
/Jacob Carlborg