How can I write compile-time (pure) BigInt computations?

[Chris Dew]

I didn't know that, CTFE is really flexible.

I've filed the bug http://d.puremagic.com/issues/show_bug.cgi?id=6850
even though it won't hinder me.

Thanks,

Chris.

On 25 October 2011 12:25, Gor Gyolchanyan <gor.f.gyolchanyan at gmail.com> wrote:
> CTFE does not require purity. Your error is not CTFE-specific.
> It's a bug in BigInt's implementation, because the opBinary(string op
> : "%") is not marked pure as it should be.
>
> On Tue, Oct 25, 2011 at 3:05 PM, Chris Dew <cmsdew at gmail.com> wrote:
>> I would like to do some expensive BigInt computation at compile-time.
>>
>> The basic arithmetic operations on BigInt seem to be impure, which
>> seems to make this impossible.
>>
>> How can I work round this?
>>
>> Thanks,
>>
>> Chris.
>>
>>
>> gcd.d:
>>
>> import std.stdio;
>> import std.bigint;
>>
>> pure BigInt gcd(BigInt a, BigInt b) {  if (b == 0) return a;  return
>> gcd(b, a % b);}
>> int main() {  BigInt n = "10000000000";  writefln("%s", gcd(cast(BigInt)48, n));
>>   return 0;}
>> ./gcd.d(6): Error: pure function 'gcd' cannot call impure function 'opBinary'
>> Failed: dmd  -v -o- './gcd.d' -I'.' >./gcd.d.deps
>>
>