Final by default?

[Paulo Pinto]

Am 14.03.2014 19:06, schrieb Iain Buclaw:
> On 14 March 2014 17:53, Walter Bright <newshound2 at digitalmars.com> wrote:
>> On 3/14/2014 10:26 AM, Johannes Pfau wrote:
>>>
>>> I use manifest constants instead of version identifiers as well. If a
>>> version identifier affects the public API/ABI of a library, then the
>>> library and all code using the library always have to be compiled with
>>> the same version switches(inlining and templates make this an even
>>> bigger problem). This is not only inconvenient, it's also easy to think
>>> of examples where the problem will only show up as crashes at runtime.
>>> The only reason why that's not an issue in phobos/druntime is that we
>>> only use compiler defined versions there, but user defined versions are
>>> almost unusable.
>>
>>
>> Use this method:
>>
>>
>>      --------
>>      import wackyfunctionality;
>>      ...
>>      WackyFunction();
>>      --------
>>      module wackyfunctionality;
>>
>>      void WackyFunction() {
>>          version (Linux)
>>            SomeWackyFunction();
>>          else version (OSX)
>>              SomeWackyFunction();
>>          else
>>              ... workaround ...
>>      }
>>      --------
>
>
> Some years down the line (and some platform testing) turns into:
>
> --------
> module wackyfunctionality;
>
> void WackyFunction() {
>      version (Linux) {
>          version (ARM)
>              _SomeWackyFunction();
>          else version (MIPS)
>             MIPS_SomeWackyFunction();
>          else version (X86)
>             SomeWackyFunction();
>          else version (X86_64)
>             SomeWackyFunction();
>          else
>            ... should be some wacky function, but workaround for general case ...
>      }
>      else version (OSX) {
>          version (PPC)
>             iSomeWackyFunction();
>          else
>             SomeWackyFunction();   // In hope there's no other Apple hardware.
>      }
>      else version (OpenBSD) {
>        /// Blah
>      }
>      else version (Haiku) {
>        /// Blah
>      }
>      else
>          ... workaround ...
> }
> --------
>


That is why the best approach is to have one module per platform 
specific code, with a common interface defined in .di file.

Back on my C/C++ days at work, any conditional code would be killed by 
me during code reviews.

--
Paulo