Is there any reason why the following code fails to compile?

---
auto bfalse = to!bool(0);
auto btrue = to!bool(1);
---
dmd2/src/phobos/std/conv.d(329): Error: template std.conv.toImpl
cannot deduce template function from argument types !(bool)(int)


I can use a string, like so:
---
auto bfalse = to!bool("false");
auto btrue = to!bool("true");
---
...but usually the database column is an INTEGER type.

I can cast(bool)(0) or cast(bool)(1) no problem but I much prefer
to!bool.

Thanks,
G.

On Tuesday, 27 August 2013 at 04:08:47 UTC, growler wrote:
> Is there any reason why the following code fails to compile?
>
> ---
> auto bfalse = to!bool(0);
> auto btrue = to!bool(1);
> ---
> dmd2/src/phobos/std/conv.d(329): Error: template std.conv.toImpl
> cannot deduce template function from argument types !(bool)(int)

No one implemented probably. BTW:

void main() {
     bool a = 0;
     bool b = 1;

     assert(!a);
     assert(b);
}

On Tue, Aug 27, 2013 at 07:12:56AM +0200, Jesse Phillips wrote:
> On Tuesday, 27 August 2013 at 04:08:47 UTC, growler wrote:
> >Is there any reason why the following code fails to compile?
> >
> >---
> >auto bfalse = to!bool(0);
> >auto btrue = to!bool(1);
> >---
> >dmd2/src/phobos/std/conv.d(329): Error: template std.conv.toImpl
> >cannot deduce template function from argument types !(bool)(int)
> 
> No one implemented probably. BTW:
> 
> void main() {
>      bool a = 0;
>      bool b = 1;
> 
>      assert(!a);
>      assert(b);
> }

Hmm. Maybe file an enhancement request here:

	http://d.puremagic.com/issues


T

-- 
"I'm not childish; I'm just in touch with the child within!" - RL

On Tuesday, 27 August 2013 at 05:13:01 UTC, Jesse Phillips wrote:
> On Tuesday, 27 August 2013 at 04:08:47 UTC, growler wrote:
>> Is there any reason why the following code fails to compile?
>>
>> ---
>> auto bfalse = to!bool(0);
>> auto btrue = to!bool(1);
>> ---
>> dmd2/src/phobos/std/conv.d(329): Error: template std.conv.toImpl
>> cannot deduce template function from argument types !(bool)(int)
>
> No one implemented probably. BTW:

No worries, thanks for the info.

>
> void main() {
>      bool a = 0;
>      bool b = 1;
>
>      assert(!a);
>      assert(b);
> }

The implicit conversion is only for literals and besides, I have
this sort of hackiness happening:

alias typeof(s.tueplof[ii]) FieldType;
s.tupleof[ii] = value.to!FieldType;

I just stick in a static-if(isBoolean!FieldType) and all is well.

Thanks,
G

On Tuesday, 27 August 2013 at 05:22:00 UTC, H. S. Teoh wrote:
> On Tue, Aug 27, 2013 at 07:12:56AM +0200, Jesse Phillips wrote:
>> On Tuesday, 27 August 2013 at 04:08:47 UTC, growler wrote:
>> >Is there any reason why the following code fails to compile?
>> >
>> >---
>> >auto bfalse = to!bool(0);
>> >auto btrue = to!bool(1);
>> >---
>> >dmd2/src/phobos/std/conv.d(329): Error: template std.conv.toImpl
>> >cannot deduce template function from argument types !(bool)(int)
>> 
>> No one implemented probably. BTW:
>> 
>> void main() {
>>      bool a = 0;
>>      bool b = 1;
>> 
>>      assert(!a);
>>      assert(b);
>> }
>
> Hmm. Maybe file an enhancement request here:
>
> 	http://d.puremagic.com/issues
>
>
> T

Done.

http://d.puremagic.com/issues/show_bug.cgi?id=10909

Thanks,
G.