Feels pretty silly, but I can't compile this:


import std.random;
auto i = uniform(0, 10);


DMD spits this:

/usr/include/dmd/phobos/std/random.d(1188): Error: static variable initialized cannot be read at compile time
/usr/include/dmd/phobos/std/random.d(1231):        called from here: rndGen()
/usr/include/dmd/phobos/std/random.d(1231):        called from here: uniform(a, b, rndGen())


Perhaps I'm missing something obvious?
dmd 2.067.1, openSUSE 13.2 x64

On Sunday, 3 May 2015 at 08:42:57 UTC, tired_eyes wrote:
> Feels pretty silly, but I can't compile this:
>
>
> import std.random;
> auto i = uniform(0, 10);
>
>
> DMD spits this:
>
> /usr/include/dmd/phobos/std/random.d(1188): Error: static variable initialized cannot be read at compile time
> /usr/include/dmd/phobos/std/random.d(1231):        called from here: rndGen()
> /usr/include/dmd/phobos/std/random.d(1231):        called from here: uniform(a, b, rndGen())
>
>
> Perhaps I'm missing something obvious?
> dmd 2.067.1, openSUSE 13.2 x64

void main() {
	import std.random;
	auto i = uniform(0, 10);
}

On Sunday, 3 May 2015 at 08:48:52 UTC, Dennis Ritchie wrote:
> On Sunday, 3 May 2015 at 08:42:57 UTC, tired_eyes wrote:
>> Feels pretty silly, but I can't compile this:
>>
>>
>> import std.random;
>> auto i = uniform(0, 10);
>>
>>
>> DMD spits this:
>>
>> /usr/include/dmd/phobos/std/random.d(1188): Error: static variable initialized cannot be read at compile time
>> /usr/include/dmd/phobos/std/random.d(1231):        called from here: rndGen()
>> /usr/include/dmd/phobos/std/random.d(1231):        called from here: uniform(a, b, rndGen())
>>
>>
>> Perhaps I'm missing something obvious?
>> dmd 2.067.1, openSUSE 13.2 x64
>
> void main() {
> 	import std.random;
> 	auto i = uniform(0, 10);
> }

Not so simple, unfortunately.
Actual code:


import std.random;

struct Mystruct {
    auto id = uniform(0, 10);
}

void main() {
    // wahtever
}


..and no luck.

On Sunday, 3 May 2015 at 09:04:07 UTC, tired_eyes wrote:
> On Sunday, 3 May 2015 at 08:48:52 UTC, Dennis Ritchie wrote:
>> On Sunday, 3 May 2015 at 08:42:57 UTC, tired_eyes wrote:
>>> Feels pretty silly, but I can't compile this:
>>>
>>>
>>> import std.random;
>>> auto i = uniform(0, 10);
>>>
>>>
>>> DMD spits this:
>>>
>>> /usr/include/dmd/phobos/std/random.d(1188): Error: static variable initialized cannot be read at compile time
>>> /usr/include/dmd/phobos/std/random.d(1231):        called from here: rndGen()
>>> /usr/include/dmd/phobos/std/random.d(1231):        called from here: uniform(a, b, rndGen())
>>>
>>>
>>> Perhaps I'm missing something obvious?
>>> dmd 2.067.1, openSUSE 13.2 x64
>>
>> void main() {
>> 	import std.random;
>> 	auto i = uniform(0, 10);
>> }
>
> Not so simple, unfortunately.
> Actual code:
>
>
> import std.random;
>
> struct Mystruct {
>     auto id = uniform(0, 10);
> }
>
> void main() {
>     // wahtever
> }
>
>
> ..and no luck.

I think it is a bug:

import std.stdio, std.random;

struct Mystruct {
	//mixin(`auto id = uniform(0, 10);`);
	// Error: static variable initialized cannot be read at compile time
	int val;
}

void main() {

	Mystruct test;

	test.val = uniform(0, 10); // OK
	writeln(test.val);

	mixin(`auto n = uniform(0, 10);`); // OK
}

Hmmm.

hap.random from http://code.dlang.org/packages/hap behaves exactly the same.

On Sunday, 3 May 2015 at 09:28:40 UTC, Dennis Ritchie wrote:
> On Sunday, 3 May 2015 at 09:04:07 UTC, tired_eyes wrote:
>> On Sunday, 3 May 2015 at 08:48:52 UTC, Dennis Ritchie wrote:
>>> On Sunday, 3 May 2015 at 08:42:57 UTC, tired_eyes wrote:
>>>> Feels pretty silly, but I can't compile this:
>>>>
>>>>
>>>> import std.random;
>>>> auto i = uniform(0, 10);
>>>>
>>>>
>>>> DMD spits this:
>>>>
>>>> /usr/include/dmd/phobos/std/random.d(1188): Error: static variable initialized cannot be read at compile time
>>>> /usr/include/dmd/phobos/std/random.d(1231):        called from here: rndGen()
>>>> /usr/include/dmd/phobos/std/random.d(1231):        called from here: uniform(a, b, rndGen())
>>>>
>>>>
>>>> Perhaps I'm missing something obvious?
>>>> dmd 2.067.1, openSUSE 13.2 x64
>>>
>>> void main() {
>>> 	import std.random;
>>> 	auto i = uniform(0, 10);
>>> }
>>
>> Not so simple, unfortunately.
>> Actual code:
>>
>>
>> import std.random;
>>
>> struct Mystruct {
>>    auto id = uniform(0, 10);
>> }
>>
>> void main() {
>>    // wahtever
>> }
>>
>>
>> ..and no luck.
>
> I think it is a bug:

No. The aboc code defines a field of Mystruct calld 'id', with a type inferred from the static initializer expression 'uniform(0, 10)'. The problem is that a static initializer is... static! So the expression must be evaluated at compile-time. The uniform generator from std.random cannot be used at compile-time, thus the error.

You could do:
---
import std.random;

struct Mystruct {
	int id;
	
	static opCall() {
		Mystruct s;
		s.id = uniform(0, 10);
		return s;
	}
}

void main() {
    auto s = Mystruct();
	// whatever
}
---

> import std.random;
>
> struct Mystruct {
> 	int id;
> 	
> 	static opCall() {
> 		Mystruct s;
> 		s.id = uniform(0, 10);
> 		return s;
> 	}
> }
>
> void main() {
>     auto s = Mystruct();
> 	// whatever
> }
> ---

This make sense, thant you for the explanation.