Hi,

I have problems to convert a char[4] to an uint at compile time. All variations (I've tried) of using an enum crashes dmd:

union pp { char[4] str; uint num; }
const uint x = pp("abcd").num

This does also doesn't work:

const uint x = cast(uint) x"aa aa aa aa";


Any ideas?

Reply to Moritz,

> Hi,
> 
> I have problems to convert a char[4] to an uint at compile time. All
> variations (I've tried) of using an enum crashes dmd:
> 
> union pp { char[4] str; uint num; }
> const uint x = pp("abcd").num
> This does also doesn't work:
> 
> const uint x = cast(uint) x"aa aa aa aa";
> 
> Any ideas?
> 


template Go (char[4] arg)
{
   const uint Go = (arg[0] << 24) | (arg[1] << 16) | (arg[2] << 8) | arg[3];
}

import std.stdio;
void main()
{
  writef("%x\n", Go!("Good"));
}

On Tue, 16 Dec 2008 19:54:11 +0000, BCS wrote:

> Reply to Moritz,
> 
>> Hi,
>> 
>> I have problems to convert a char[4] to an uint at compile time. All variations (I've tried) of using an enum crashes dmd:
>> 
>> union pp { char[4] str; uint num; }
>> const uint x = pp("abcd").num
>> This does also doesn't work:
>> 
>> const uint x = cast(uint) x"aa aa aa aa";
>> 
>> Any ideas?
>> 
>> 
> 
> template Go (char[4] arg)
> {
>     const uint Go = (arg[0] << 24) | (arg[1] << 16) | (arg[2] << 8) |
>     arg[3];
> }
> 
> import std.stdio;
> void main()
> {
>    writef("%x\n", Go!("Good"));
> }

Thanks!
That workaround should do it.

Maybe it will be possible to just do cast(uint) "abcd" in the future. :>

Moritz Warning wrote:
> On Tue, 16 Dec 2008 19:54:11 +0000, BCS wrote:
> 
>> Reply to Moritz,
>>
>>> Hi,
>>>
>>> I have problems to convert a char[4] to an uint at compile time. All
>>> variations (I've tried) of using an enum crashes dmd:
>>>
>>> union pp { char[4] str; uint num; }
>>> const uint x = pp("abcd").num
>>> This does also doesn't work:
>>>
>>> const uint x = cast(uint) x"aa aa aa aa";
>>>
>>> Any ideas?
>>>
>>>
>> template Go (char[4] arg)
>> {
>>     const uint Go = (arg[0] << 24) | (arg[1] << 16) | (arg[2] << 8) |
>>     arg[3];
>> }
>>
>> import std.stdio;
>> void main()
>> {
>>    writef("%x\n", Go!("Good"));
>> }
> 
> Thanks!
> That workaround should do it.
> 
> Maybe it will be possible to just do cast(uint) "abcd" in the future. :>

That would only cast the pointer.  It should be something like : cast(uint)(*"abcs") or *cast(uint*) "abcs".

-Joel

On Tue, 23 Dec 2008 11:07:08 +0300, Janderson <ask@me.com> wrote:

> Moritz Warning wrote:
>> On Tue, 16 Dec 2008 19:54:11 +0000, BCS wrote:
>>
>>> Reply to Moritz,
>>>
>>>> Hi,
>>>>
>>>> I have problems to convert a char[4] to an uint at compile time. All
>>>> variations (I've tried) of using an enum crashes dmd:
>>>>
>>>> union pp { char[4] str; uint num; }
>>>> const uint x = pp("abcd").num
>>>> This does also doesn't work:
>>>>
>>>> const uint x = cast(uint) x"aa aa aa aa";
>>>>
>>>> Any ideas?
>>>>
>>>>
>>> template Go (char[4] arg)
>>> {
>>>     const uint Go = (arg[0] << 24) | (arg[1] << 16) | (arg[2] << 8) |
>>>     arg[3];
>>> }
>>>
>>> import std.stdio;
>>> void main()
>>> {
>>>    writef("%x\n", Go!("Good"));
>>> }
>>  Thanks!
>> That workaround should do it.
>>  Maybe it will be possible to just do cast(uint) "abcd" in the future. :>
>
> That would only cast the pointer.  It should be something like : cast(uint)(*"abcs") or *cast(uint*) "abcs".
>
> -Joel

And what about endianness? You can't have a feature in a language that gives different results in different environment.

On Tue, 23 Dec 2008 00:07:08 -0800, Janderson wrote:

> Moritz Warning wrote:
>> On Tue, 16 Dec 2008 19:54:11 +0000, BCS wrote:
>> 
>>> Reply to Moritz,
>>>
>>>> Hi,
>>>>
>>>> I have problems to convert a char[4] to an uint at compile time. All variations (I've tried) of using an enum crashes dmd:
>>>>
>>>> union pp { char[4] str; uint num; }
>>>> const uint x = pp("abcd").num
>>>> This does also doesn't work:
>>>>
>>>> const uint x = cast(uint) x"aa aa aa aa";
>>>>
>>>> Any ideas?
>>>>
>>>>
>>> template Go (char[4] arg)
>>> {
>>>     const uint Go = (arg[0] << 24) | (arg[1] << 16) | (arg[2] << 8) |
>>>     arg[3];
>>> }
>>>
>>> import std.stdio;
>>> void main()
>>> {
>>>    writef("%x\n", Go!("Good"));
>>> }
>> 
>> Thanks!
>> That workaround should do it.
>> 
>> Maybe it will be possible to just do cast(uint) "abcd" in the future.
>> :>
> 
> That would only cast the pointer.  It should be something like :
> cast(uint)(*"abcs") or *cast(uint*) "abcs".
> 
> -Joel

I like to see "abcd" being a value type like a decimal or hex value. A cast(uint) would be possible and nice in that case.

On Tue, 23 Dec 2008 13:16:28 +0300, Denis Koroskin wrote:

> On Tue, 23 Dec 2008 11:07:08 +0300, Janderson <ask@me.com> wrote:
> 
>> Moritz Warning wrote:
>>> On Tue, 16 Dec 2008 19:54:11 +0000, BCS wrote:
>>>
>>>> Reply to Moritz,
>>>>
>>>>> Hi,
>>>>>
>>>>> I have problems to convert a char[4] to an uint at compile time. All variations (I've tried) of using an enum crashes dmd:
>>>>>
>>>>> union pp { char[4] str; uint num; }
>>>>> const uint x = pp("abcd").num
>>>>> This does also doesn't work:
>>>>>
>>>>> const uint x = cast(uint) x"aa aa aa aa";
>>>>>
>>>>> Any ideas?
>>>>>
>>>>>
>>>> template Go (char[4] arg)
>>>> {
>>>>     const uint Go = (arg[0] << 24) | (arg[1] << 16) | (arg[2] << 8) |
>>>>     arg[3];
>>>> }
>>>>
>>>> import std.stdio;
>>>> void main()
>>>> {
>>>>    writef("%x\n", Go!("Good"));
>>>> }
>>>  Thanks!
>>> That workaround should do it.
>>>  Maybe it will be possible to just do cast(uint) "abcd" in the future.
>>> :>
>>
>> That would only cast the pointer.  It should be something like :
>> cast(uint)(*"abcs") or *cast(uint*) "abcs".
>>
>> -Joel
> 
> And what about endianness? You can't have a feature in a language that gives different results in different environment.

The use of uint in my example might be confusing.
I only needed an environment independent bit pattern of 4 bytes.
An integer is used because it's faster than comparing a char[4]
with DMD. :/

(GDC doesn't show such behavior)