_obsolete_dont_use/udas.d

   1 /* Invisible Vector Library
   2  * coded by Ketmar // Invisible Vector <ketmar@ketmar.no-ip.org>
   3  * Understanding is not required. Only obedience.
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, version 3 of the License ONLY.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  16  */
  17 // severely outdated! do not use!
  18 module iv.udas /*is aliced*/;
  19 import iv.alice;
  20
  21 private alias aliasHelper(alias T) = T;
  22 private alias aliasHelper(T) = T;
  23
  24
  25 template hasUDA(alias T, alias uda) {
  26   static template Has(alias uda, lst...) {
  27     static if (lst.length == 0)
  28       enum Has = false;
  29     else static if (is(aliasHelper!(lst[0]) == uda) || is(typeof(lst[0]) == uda))
  30       enum Has = true;
  31     else
  32       enum Has = Has!(uda, lst[1..$]);
  33   }
  34   enum hasUDA = Has!(uda, __traits(getAttributes, T));
  35 }
  36
  37
  38 template getUDA(alias T, alias uda) {
  39   template Find(lst...) {
  40     static if (lst.length == 0)
  41       static assert(0, "uda '"~uda.stringof~"' not found in type '"~T.stringof~"'");
  42     else static if (is(aliasHelper!(lst[0]) == uda) || is(typeof(lst[0]) == uda))
  43       enum Find = lst[0];
  44     else
  45       enum Find = Find!(lst[1..$]);
  46   }
  47   enum getUDA = Find!(__traits(getAttributes, T));
  48 }
  49
  50
  51 unittest {
  52   enum testuda0;
  53   struct testuda1 {}
  54
  55   struct A {
  56     @A string bar;
  57   }
  58
  59   @testuda1 struct Foo {
  60     @A("foo")
  61     int i;
  62     @testuda0 string s;
  63   }
  64
  65   static assert(!hasUDA!(Foo, A));
  66   static assert(hasUDA!(Foo, testuda1));
  67   static assert(hasUDA!(Foo.i, A));
  68   static assert(getUDA!(Foo.i, A).bar == "foo");
  69
  70   //even uda-inception works
  71   static assert(hasUDA!(getUDA!(Foo.i, A).bar, A));
  72   static assert(!hasUDA!(getUDA!(Foo.i, A).bar, testuda1));
  73 }