Multiple return values...
Derek
ddparnell at bigpond.com
Thu Mar 15 02:52:13 PDT 2012
On Thu, 15 Mar 2012 19:23:57 +1100, Timon Gehr <timon.gehr at gmx.ch> wrote:
>> I'd like to break the nexus between science and magic here.
>>
>
> // this is used to access language built-in tuples
> template to(T...) {
> alias T to;
> }
>
> // this builds a struct akin to std.typecons.tuple
> // it contains the function parameters as fields t[0], t[1],...
> auto from(T...)(T t) {
> struct Result { T t; alias t this; }
> return Result( t );
> }
>
> // to!(a,b) creates a tuple containing aliases to a and b
>
> to!(a,b) = from(b,a); // cannot assign Result to two fields
> to!(a,b) = from(b,a).t; // try alias this
> auto __tmp = from(b,a).t; // expand tuple assign to multiple assignment
> a[0] = __tmp[0], a[1] = __tmp[1];
Thanks, but I was hoping more for an explanation in English.
Are you saying that the generated code is something like ...
struct __tmpS { int Fa, int Fb };
__tempS __tmp;
__tmp.Fa = a;
__tmp.Fb = b;
a = __tmp.Fb;
b = __tmp.Fa;
--
Derek Parnell
Melbourne, Australia
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