How do you use templates in D?

[Andrew Pennebaker]

bearophile: Aw shucks, every single link to the old D ports is broken. Even
Fawzi took down his RTest project. I'll message him to ask that he reupload
it.

Cheers,

Andrew Pennebaker
www.yellosoft.us

On Tue, Oct 18, 2011 at 4:06 PM, Andrew Pennebaker <
andrew.pennebaker at gmail.com> wrote:

> bearophile, Awesome! I'll take a look at the old D ports to see how they
> did it.
>
> Çehreli, thanks much! Another D user suggested the same fixes at
> StackOverflow, so my project is making progress.
>
> Fawcett, you've got the right idea :) The difference between your example
> code and QuickCheck is that your example looks more like assert statements,
> and QuickCheck's forAll() generates the assertions dynamically, by the
> hundreds. The API has you specifying only the property to be tested, and the
> generators for its input types. You're definitely on the right track.
>
> Cheers,
>
> Andrew Pennebaker
> www.yellosoft.us
>
> On Tue, Oct 18, 2011 at 3:48 PM, Graham Fawcett <fawcett at uwindsor.ca>wrote:
>
>> On Tue, 18 Oct 2011 15:06:21 -0400, Andrew Pennebaker wrote:
>>
>> > Recap:
>> >
>> > forAll() accepts a property of type bool function(void), and a
>> > collection of generator functions, of types *arbitrary_type*
>> > function(void). forAll calls the generator functions, storing the values
>> > in another collection, and passing the values to the property. If the
>> > property returns false, the values are printed to the screen.
>>
>> A variadic forAll seems doable, e.g.
>>
>>  forAll!isEven(&my_ints, &my_floats, &my_ulongs);
>>
>> The types are not *entirely* arbitrary, right? Each has a return type Tn,
>> constrained such that "isEven!Tn" must be a valid instance of the isEven
>> template. so "forAll!isEven(&ints, &floats, &bananas)" would be invalid,
>> assuming there's no legal "isEven!Banana" instance.
>>
>> It would look something like this (here with arrays, instead of lambdas):
>>
>> import std.stdio;
>>
>> bool isEven(T)(T v) {
>>  return v % 2 == 0;
>> }
>>
>> bool forAll(alias Pred, T...)(T seqs) {
>>  bool result = true;
>>  foreach(sequence; seqs) {
>>    foreach(elem; sequence)
>>      result &= Pred(elem);
>>  }
>>  return result;
>> }
>>
>> void main() {
>>  writeln(forAll!isEven([22, 22], [23L, 22L]));
>>  writeln(forAll!isEven([2,4], [6.0,8.0], [10L,12L]));
>> }
>>
>> Graham
>>
>>
>
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