alias with lambda syntax: alias fun2=a=fun(a);

[Timothee Cour via Digitalmars-d-learn]

Is there a way to do this?

import std.algorithm;

auto fun(T)(T a){return a;}

template fun2(T){auto fun2(T a){return fun(a);}}//OK but heavy syntax and
cannot be nested inside test()

void main(){
  //alias fun2=fun!int; //OK but needs to specify template params
  //none of those work:
  //alias fun2=a=fun(a);
  //alias fun2(T)=(T a)=fun(a);
  //alias fun2(T)=(T a){return fun(a);}
  auto b=[1].map!fun2;
  assert(b.equal([1]));
}

Re: alias with lambda syntax: alias fun2=a=fun(a);

[timotheecour via Digitalmars-d-learn]

On Thursday, 5 June 2014 at 06:58:50 UTC, Timothee Cour via
Digitalmars-d-learn wrote:

Is there a way to do this?

import std.algorithm;

auto fun(T)(T a){return a;}

template fun2(T){auto fun2(T a){return fun(a);}}//OK but heavy 
syntax and

cannot be nested inside test()

void main(){
  //alias fun2=fun!int; //OK but needs to specify template 
params

  //none of those work:
  //alias fun2=a=fun(a);
  //alias fun2(T)=(T a)=fun(a);
  //alias fun2(T)=(T a){return fun(a);}
  auto b=[1].map!fun2;
  assert(b.equal([1]));
}


ok I remembered we can use std.typetuple.Alias for that.

Re: alias with lambda syntax: alias fun2=a=fun(a);

[Timothee Cour via Digitalmars-d-learn]

ok I remembered we can use std.typetuple.Alias for that.


On Wed, Jun 4, 2014 at 11:58 PM, Timothee Cour thelastmamm...@gmail.com
wrote:

 Is there a way to do this?

 import std.algorithm;

 auto fun(T)(T a){return a;}

 template fun2(T){auto fun2(T a){return fun(a);}}//OK but heavy syntax and
 cannot be nested inside test()

 void main(){
   //alias fun2=fun!int; //OK but needs to specify template params
   //none of those work:
   //alias fun2=a=fun(a);
   //alias fun2(T)=(T a)=fun(a);
   //alias fun2(T)=(T a){return fun(a);}
   auto b=[1].map!fun2;
   assert(b.equal([1]));
 }

Re: alias with lambda syntax: alias fun2=a=fun(a);

[Artur Skawina via Digitalmars-d-learn]

On 06/05/14 08:58, Timothee Cour via Digitalmars-d-learn wrote:
 Is there a way to do this?
 
 auto fun(T)(T a){return a;}
 
 template fun2(T){auto fun2(T a){return fun(a);}}//OK but heavy syntax and 
 cannot be nested inside test()
  
   alias fun2(T) = fun!T;

But this will prevent IFTI, so you'd either need to use 'fun2!int' or
introduce another alias ...

 void main(){
   //alias fun2=fun!int; //OK but needs to specify template params

... like this one.

If you want the params inferred, then

   static auto ref fun2(A...)(A a) { return fun(a); }

will mostly work. [1]

   //none of those work:
   //alias fun2=a=fun(a);
   //alias fun2(T)=(T a)=fun(a);
   //alias fun2(T)=(T a){return fun(a);}
   auto b=[1].map!fun2;
   assert(b.equal([1]));
 }
 

artur

[1] no perfect forwarding; there's no terse way to do that in D.

Re: alias with lambda syntax: alias fun2=a=fun(a);

[Artur Skawina via Digitalmars-d-learn]

 On 06/05/14 08:58, Timothee Cour via Digitalmars-d-learn wrote:

   //none of those work:
   //alias fun2=a=fun(a);

  alias fun2=ALIAS!(a=fun(a));

That 'ALIAS' template will need to be in module scope.
  
  alias ALIAS(alias A) = A;

artur

Re: alias with lambda syntax: alias fun2=a=fun(a);

[Meta via Digitalmars-d-learn]

On Thursday, 5 June 2014 at 07:19:07 UTC, timotheecour wrote:

ok I remembered we can use std.typetuple.Alias for that.


Or std.functional.unaryFun.