Experimental approach to reference-type random number generators

[Joseph Rushton Wakeling]

On 24/08/13 20:35, Joseph Rushton Wakeling wrote:
> I do have one specific query

Actually, two.  Lines 448-457 of the second codepad paste have this unittest, 
with the last line commented out:


     // Check .save works
     foreach (Type; TypeTuple!(MinstdRand0, MinstdRand))
     {
         auto rnd1 = Type(unpredictableSeed);
         auto rnd2 = rnd1.save;
         //assert(rnd1 == rnd2);
         // Enable next test when RNGs are reference types
         version(none) { assert(rnd1 !is rnd2); }
         //assert(rnd1.take(100).array() == rnd2.take(100).array());
     }

If the last assert is uncommented,

     assert(rnd1.take(100).array() == rnd2.take(100).array());

... then running the unittests results in the following error:

     /opt/dmd/include/d2/std/array.d(37): Error: variable 
std.array.array!(Take!(RandomGenerator!(LinearCongruentialEngine!(uint, 16807, 
0, 2147483647)))).array.r has scoped destruction, cannot build closure

This is rather worrying and I'm concerned that this could be a fundamental flaw 
in the whole design.  Can anyone advise on how to fix it?