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digitalmars.D - Allow auto in function parameters with default arguments?

reply Andrej Mitrovic <andrej.mitrovich gmail.com> writes:
It occurred to me that using a parameter with a default value that is
a function call could benefit from using auto:

struct Foo(T) { }

auto getFoo()
{
    return Foo!int();
}

void func(int x, auto foo = getFoo()) { }

Granted this is a simple case and might be overkill, but if the
function returns some complicated range type (or worse, a Voldemort
type) it might be hard or impossible to specify the type.
Sep 09 2012
next sibling parent reply Timon Gehr <timon.gehr gmx.ch> writes:
On 09/10/2012 06:20 AM, Andrej Mitrovic wrote:

 It occurred to me that using a parameter with a default value that is
 a function call could benefit from using auto:

 struct Foo(T) { }

 auto getFoo()
 {
      return Foo!int();
 }

 void func(int x, auto foo = getFoo()) { }

 Granted this is a simple case and might be overkill,


As parameter names are optional, foo is parsed as the parameter type in
this case. What exact change do you propose?


 but if the function returns some complicated range type (or worse, a Voldemort
 type) it might be hard or impossible to specify the type.


Every type that you can get hold of a value of can be specified by the 
means of typeof.
Sep 10 2012
parent Andrej Mitrovic <andrej.mitrovich gmail.com> writes:
On 9/10/12, Timon Gehr <timon.gehr gmx.ch> wrote:

 Every type that you can get hold of a value of can be specified by the
 means of typeof.


Yeah but it's repetitive. typeof(exp) arg = exp;
Sep 10 2012
prev sibling parent reply "Mehrdad" <wfunction hotmail.com> writes:
http://forum.dlang.org/thread/is9jmn$2ia5$1 digitalmars.com
Sep 10 2012
parent Artur Skawina <art.08.09 gmail.com> writes:
On 09/11/12 08:21, Mehrdad wrote:

 http://forum.dlang.org/thread/is9jmn$2ia5$1 digitalmars.com


Completely different issue. That one is about syntax sugar for template
functions, while this one would just save the programmer some typing when
declaring "normal" functions (by propagating the type of the default
argument expression, which would make it possible to skip the redundant
'typeof(expr)' part).

artur
Sep 11 2012