Wiadomo=B6=E6 napisana pr= zez Herb Sutter <hsutter@micros= oft.com> w dniu 20 gru 2012, o godz. 21:09:

Composition and currying are cool.
<= o:p>
Those who don’t like the ters= e syntax may object that it’s only slightly worse with the current sy= ntax, though, right?

auto compose =3D []( auto f, auto g ) { return
    [=3D]( auto x ) f( g(x) ); };=

auto curry3 =3D
   []( auto f = ) { return
     = [=3D](auto x) { return [=3D](auto y) { return [=3D](auto z) { return=
      &nbs= p;    f(x,y,z); }; }; }; };
Though you do have to be a littl= e careful to balance the {‘s and };’s.

Herb
From: = ;Scott Prager [mailto:splinterofchaos@gmail.com]
Sent: Thursday, December 20, 2012 10:16 AM
= To: std-proposals@isocpp.org
Cc: std-discussion@isocpp.or= g; fa= isalv@gmail.com
Subject: [std-proposals] Re: An implementation of Generic lambdas (Req= uest for feedback)
Absolutely fa= ntastic! A few things on interest:

I had not realized this syntax su= pports nesting:
compose =3D []( auto f, g )
= [=3D]( auto<= span class=3D"Apple-converted-space"> x ) f( g(x)= );
<= br>auto curr= y3 =3D
[]( auto= f )
= [=3D](<= /span>auto x= ) [=3D](auto y) [=3D](auto z <= br> &n= bsp;f(<= /span>x,y,z);
And v=
ariadic lambdas, too! Very nice. 
But I wonder =
why we couldn't...
auto f =3D []( <=
span style=3D"color: rgb(0, 0, 136); ">auto _f ) [](auto ...x) _f(x...);
I wrote some tests. A few lines caused the comp=
iler to crash so I commented them out and labelled them "Crash!".
https://gist.github.com/43471=
30
On= Monday, December 17, 2012 2:05:37 PM UTC-5, faisalv wrote:
Motivated by the positive feedback we received rega= rding Generic
Lambdas= (during the October 2012 ISO C++ Standards Meeting in
Portland), I have implemented a reasonabl= y complete (unless I am <= br>missing something obvious) implementation
(= http://faisalv.github.com/clang-glambda/) of most of the proposal
(named lambda syntax for f= unctions has not been attempted) using a
fork of clang.&nb= sp;

We would like to encourage developers who are interested = in this
feature, to e= ither compile the code or download the binaries (sorry,
only windows for now) and play with the = implementation and provide us
with feedback so that we can incorporate it within our next revisi= on
of the document.

The following link= : http://faisalv.github.com/clang-glambda/, ha= s some
instructions (= towards the bottom) on how to compile the code or use
the binaries for windows.

Any and all constructive feedback= will be greatly appreciated.

The current version (12/2012) implements subproposals 2.1, 2.2= , 2.3 and 2.5.

2.= 1 Allow the type-specifier within a parameter declaration of a
lambda to be auto (i.e. auto is= mandatory)

auto = Sum =3D [](auto a, decltype(a) b) { return a + b; };
int i =3D Sum(3, 4);
double d =3D Sum(3.14, 2.77);

2.2 Allow the use of familiar = template syntax in lambda expressions=

auto NumElements =3D []<int N>(auto (&a)[N])= { return N; };
int a= rri[]{1, 2, 3};
doubl= e arrd[]{3.14, 2.77, 6.626};
auto total =3D NumElements(arri) + NumElements(arrd);

2.3 Permit a lambda body to be= an expression

in= t local =3D 10;
auto = L =3D [&](auto a) a + ++local;&nb= sp;

2.5 Autogenerate a conversion to function pointer in capt= ureless generic lambdas <= br>
auto L =3D [](auto a, decltype(a) b) { return a + b; };
int (*fp)(int, int) =3D L;

Thank you and loo= king forward to the feedback!
--

&nbs= p;
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