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digitalmars.D - Copying parameter lists verbatim

reply Manu via Digitalmars-d <digitalmars-d puremagic.com> writes:
So, about 2 years back I motivated a bunch of work on traits relating to
parameter lists.
I'm looking at std.traits now, but I can't see one of the things that I
could have sworn was added at the time.

I need to clone a functions parameter list, including the names and default
args. Ie.

  void f(int x, float y = 10);
  void myFunc(CloneParameterList!f)
  assert(myFunc.stringof == "void myFunc(int x, float y = 10)");

It wasn't that, but I recall agreeing that it was possible now... but I
can't see how to do it.
I thought it was implemented using a __traits, but nothing stands out to me.

Looking at the source in std.traits, it refers to FunctionTypeOf, which I
don't recall anything about when we were implementing this stuff initially.
Perhaps there's been further development and changes since I last looked at
it...?

Anyway, does anybody know a nice tidy way to do it?
Jul 18 2014
next sibling parent reply "Dicebot" <public dicebot.lv> writes:
http://dlang.org/phobos/std_traits.html#ParameterIdentifierTuple
http://dlang.org/phobos/std_traits.html#ParameterDefaultValueTuple
http://dlang.org/phobos/std_traits.html#ParameterTypeTuple

?
Jul 19 2014
parent "Dicebot" <public dicebot.lv> writes:
Also, vibe.d internal `cloneFunction` which generates copy of 
method/function signature with fully qualified type names (for 
mixin hygiene): 
https://github.com/rejectedsoftware/vibe.d/blob/master/source/vibe/internal/meta/codegen.d#L177
Jul 19 2014
prev sibling parent reply "Jakob Ovrum" <jakobovrum gmail.com> writes:
On Saturday, 19 July 2014 at 06:13:10 UTC, Manu via Digitalmars-d 
wrote:

 Anyway, does anybody know a nice tidy way to do it?


Unfortunately the only way to create perfect forwarding functions 
completely generically is still using an ugly string mixin that 
generates the forwarding function. A subset of forwarding 
functions can be created using templates and auto-ref, but of 
course a function template has many disadvantages to a concrete 
function (virtual functions being a good example).
Jul 19 2014
parent reply Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:
On 7/19/14, 9:36 AM, Jakob Ovrum wrote:

 On Saturday, 19 July 2014 at 06:13:10 UTC, Manu via Digitalmars-d wrote:

 Anyway, does anybody know a nice tidy way to do it?


 Unfortunately the only way to create perfect forwarding functions
 completely generically is still using an ugly string mixin that
 generates the forwarding function. A subset of forwarding functions can
 be created using templates and auto-ref, but of course a function
 template has many disadvantages to a concrete function (virtual
 functions being a good example).


How can this be encapsulated as a library artifact? -- Andrei
Jul 19 2014
parent "Jakob Ovrum" <jakobovrum gmail.com> writes:
On Saturday, 19 July 2014 at 17:40:01 UTC, Andrei Alexandrescu 
wrote:

 On 7/19/14, 9:36 AM, Jakob Ovrum wrote:

 On Saturday, 19 July 2014 at 06:13:10 UTC, Manu via 
 Digitalmars-d wrote:

 Anyway, does anybody know a nice tidy way to do it?


 Unfortunately the only way to create perfect forwarding 
 functions
 completely generically is still using an ugly string mixin that
 generates the forwarding function. A subset of forwarding 
 functions can
 be created using templates and auto-ref, but of course a 
 function
 template has many disadvantages to a concrete function (virtual
 functions being a good example).


 How can this be encapsulated as a library artifact? -- Andrei


Since the key parts of the forwarding function - the parameter 
list and attribute list - are part of the signature, the entire 
function declaration has to be mixed in. That means the function 
body has to be provided as a string argument. This tends to cause 
some seriously unreadable code. It may be a lost cause but I'm 
hoping we can amend the language to avoid that.
Jul 20 2014