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digitalmars.D.learn - Iterating a typle tuple of templates

reply bearophile <bearophileHUGS lycos.com> writes:
I am allowed to create a type tuple of function templates, but then it seems I
am not allowed to use a static foreach on that type tuple:


import std.typetuple;

int foo(T)(T x) {
    return 0;
}

void main() {
    alias TypeTuple!(foo, foo) t2;
    static assert(t2[0](0) == 0); // OK
    static assert(t2[1](0) == 0); // OK
    foreach (t; t2) {} // Error
}


Is this expected, a bug in my code, a known bug in DMD, a new DMD bug, a
limitation meant to be removed, etc?

Bye,
bearophile
Mar 03 2011
parent reply Jacob Carlborg <doob me.com> writes:
On 2011-03-04 04:37, bearophile wrote:

 I am allowed to create a type tuple of function templates, but then it seems I
am not allowed to use a static foreach on that type tuple:


 import std.typetuple;

 int foo(T)(T x) {
      return 0;
 }

 void main() {
      alias TypeTuple!(foo, foo) t2;
      static assert(t2[0](0) == 0); // OK
      static assert(t2[1](0) == 0); // OK
      foreach (t; t2) {} // Error
 }


 Is this expected, a bug in my code, a known bug in DMD, a new DMD bug, a
limitation meant to be removed, etc?

 Bye,
 bearophile



Maybe you can try something like typeof(t2) in the foreach.

-- 
/Jacob Carlborg
Mar 03 2011
next sibling parent reply bearophile <bearophileHUGS lycos.com> writes:
Jacob Carlborg:


 Maybe you can try something like typeof(t2) in the foreach.



If you mean code like this:

import std.typetuple;

int foo(T)(T x) {
     return x;
}

void main() {
     alias TypeTuple!(foo, foo) t2;
     foreach (i, t; typeof(t2)) {
         pragma(msg, t);
         assert(t2[i](i) == i); // OK
         //assert(t(i) == i); // Not OK
    }
}

It seems "t" is not useful...

Is all this Bugzilla-worthy?

Thank you, bye,
bearophile
Mar 04 2011
next sibling parent Trass3r <un known.com> writes:
bearophile Wrote:

 It seems "t" is not useful...



Yep, foreach over tuples is kinda messed up.
Same with reference tuple foreach:
http://d.puremagic.com/issues/show_bug.cgi?id=2411
Direct access doesn't work but accessing via [i] does.
Mar 04 2011
prev sibling parent Jacob Carlborg <doob me.com> writes:
On 2011-03-04 13:19, bearophile wrote:

 Jacob Carlborg:


 Maybe you can try something like typeof(t2) in the foreach.



 If you mean code like this:

 import std.typetuple;

 int foo(T)(T x) {
       return x;
 }

 void main() {
       alias TypeTuple!(foo, foo) t2;
       foreach (i, t; typeof(t2)) {
           pragma(msg, t);
           assert(t2[i](i) == i); // OK
           //assert(t(i) == i); // Not OK
      }
 }

 It seems "t" is not useful...



Yeah, that's really annoying.


 Is all this Bugzilla-worthy?

 Thank you, bye,
 bearophile





-- 
/Jacob Carlborg
Mar 04 2011
prev sibling parent "Simen kjaeraas" <simen.kjaras gmail.com> writes:
bearophile <bearophileHUGS lycos.com> wrote:


 Jacob Carlborg:


 Maybe you can try something like typeof(t2) in the foreach.



 If you mean code like this:

 import std.typetuple;

 int foo(T)(T x) {
      return x;
 }

 void main() {
      alias TypeTuple!(foo, foo) t2;
      foreach (i, t; typeof(t2)) {
          pragma(msg, t);
          assert(t2[i](i) == i); // OK
          //assert(t(i) == i); // Not OK
     }
 }

 It seems "t" is not useful...

 Is all this Bugzilla-worthy?



Yes.

-- 
Simen
Mar 04 2011