Why can't I do this:

version( linux || OSX )
{
  something common to each
}

???


This is not acceptable:

version( MinGW )
{
version = linuxOrMinGW;
}
else version( linux )
{
version = linuxOrMinGW;
}

version( linuxOrMinGW )
{
  seriously...?
}


Surely basic logical expressions within a version seem not only logical,
but also very necessary?
There must be a reason this is impossible, or else I can't believe it's not
already like that...

On 1/16/2012 8:44 AM, Manu wrote:
> Why can't I do this:
>
> version( linux || OSX )
> {
>    something common to each
> }
>
> ???
>
>
> This is not acceptable:
>
> version( MinGW )
> {
> version = linuxOrMinGW;
> }
> else version( linux )
> {
> version = linuxOrMinGW;
> }
>
> version( linuxOrMinGW )
> {
>    seriously...?
> }
>
>
> Surely basic logical expressions within a version seem not only logical,
> but also very necessary?
> There must be a reason this is impossible, or else I can't believe it's
> not already like that...

This is something I've wanted ever since I first started using D. Really annoying when you need to do the same sort of version checks across multiple modules. One workaround:

----------------
module myconfig;

version(MingW)
{
    enum bool linuxOrMingW = true;
}
else version(linux)
{
    enum bool linuxOrMingW = true;
}
else
{
    enum bool linuxOrMingW = false;
}

-----------------
module foo;

import myconfig;

static if(linuxOrMingW)
{
    ...
}

-----------------

On 2012-01-16 00:44, Manu wrote:
> Why can't I do this:
>
> version( linux || OSX )
> {
>    something common to each
> }
>
> ???
>
>
> This is not acceptable:
>
> version( MinGW )
> {
> version = linuxOrMinGW;
> }
> else version( linux )
> {
> version = linuxOrMinGW;
> }
>
> version( linuxOrMinGW )
> {
>    seriously...?
> }
>
>
> Surely basic logical expressions within a version seem not only logical,
> but also very necessary?
> There must be a reason this is impossible, or else I can't believe it's
> not already like that...

A workaround is to declare variables and use static ifs:

https://github.com/jacob-carlborg/orbit/blob/master/orbit/util/Version.d

-- 
/Jacob Carlborg

On 16 January 2012 09:28, Jacob Carlborg <doob@me.com> wrote:

> On 2012-01-16 00:44, Manu wrote:
>
>> Why can't I do this:
>>
>> version( linux || OSX )
>> {
>>   something common to each
>> }
>>
>> ???
>>
>>
>> This is not acceptable:
>>
>> version( MinGW )
>> {
>> version = linuxOrMinGW;
>> }
>> else version( linux )
>> {
>> version = linuxOrMinGW;
>> }
>>
>> version( linuxOrMinGW )
>> {
>>   seriously...?
>> }
>>
>>
>> Surely basic logical expressions within a version seem not only logical,
>> but also very necessary?
>> There must be a reason this is impossible, or else I can't believe it's
>> not already like that...
>>
>
> A workaround is to declare variables and use static ifs:
>
> https://github.com/jacob-**carlborg/orbit/blob/master/** orbit/util/Version.d<https://github.com/jacob-carlborg/orbit/blob/master/orbit/util/Version.d>


... these aren't acceptable work arounds, in this case, you're written a
whole module to subvert the insanity! :)
At bare minimum, the version list/map/table/whatever it is should be
exposed to static-if, without having to create a module like the one you
just described.

On 2012-01-16 08:33, Manu wrote:
> On 16 January 2012 09:28, Jacob Carlborg <doob@me.com
> <mailto:doob@me.com>> wrote:
>
>     On 2012-01-16 00:44, Manu wrote:
>
>         Why can't I do this:
>
>         version( linux || OSX )
>         {
>            something common to each
>         }
>
>         ???
>
>
>         This is not acceptable:
>
>         version( MinGW )
>         {
>         version = linuxOrMinGW;
>         }
>         else version( linux )
>         {
>         version = linuxOrMinGW;
>         }
>
>         version( linuxOrMinGW )
>         {
>            seriously...?
>         }
>
>
>         Surely basic logical expressions within a version seem not only
>         logical,
>         but also very necessary?
>         There must be a reason this is impossible, or else I can't
>         believe it's
>         not already like that...
>
>
>     A workaround is to declare variables and use static ifs:
>
>     https://github.com/jacob-__carlborg/orbit/blob/master/__orbit/util/Version.d
>     <https://github.com/jacob-carlborg/orbit/blob/master/orbit/util/Version.d>
>
>
> ... these aren't acceptable work arounds, in this case, you're written a
> whole module to subvert the insanity! :)
> At bare minimum, the version list/map/table/whatever it is should be
> exposed to static-if, without having to create a module like the one you
> just described.

It is a workaround that works, regardless if you think it's acceptable or not, and I've already done most of the work so you don't have to.

-- 
/Jacob Carlborg

I somewhat rarely use version anymore. I used
to use it for different client customizations
to my app, but you can't turn features on and
off in a a central file like that, since the
version= doesn't affect other modules.

I switched for a while to static if like this:

version(client_a)
 enum feature_x = true;
version(client_b)
 enum feature_x = false;


== other file ==

static if(feature_x)
  void feature_x_impl() {}



But, now, I have a way of doing it without
version, and it's even better.


client_a_config.d:
===
module app.config;
enum feature_x = true;
===

client_b_config.d:
===
module app.config;
enum feature_x = false;
===


Real file:
===
import app.config;

static if(feature_x)
 // implement
===



Then, I pick the desired version just by picking
the file on the command line.


dmd app.d client_a_config.d # build client A's version
dmd app.d client_b_config.d # build client B's version



So, there's no version stuff in there at all... I now
think version is *almost* useless. Could probably use
this for operating system versions too, putting the
common components in a shared file.

On 16 January 2012 23:19, Adam D. Ruppe <destructionator@gmail.com> wrote:

> I somewhat rarely use version anymore. I used
> to use it for different client customizations
> to my app, but you can't turn features on and
> off in a a central file like that, since the
> version= doesn't affect other modules.
>
> I switched for a while to static if like this:
>
> version(client_a)
>  enum feature_x = true;
> version(client_b)
>  enum feature_x = false;
>
>
> == other file ==
>
> static if(feature_x)
>  void feature_x_impl() {}
>
>
>
> But, now, I have a way of doing it without
> version, and it's even better.
>
>
> client_a_config.d:
> ===
> module app.config;
> enum feature_x = true;
> ===
>
> client_b_config.d:
> ===
> module app.config;
> enum feature_x = false;
> ===
>
>
> Real file:
> ===
> import app.config;
>
> static if(feature_x)
>  // implement
> ===
>
>
>
> Then, I pick the desired version just by picking
> the file on the command line.
>
>
> dmd app.d client_a_config.d # build client A's version
> dmd app.d client_b_config.d # build client B's version
>
>
>
> So, there's no version stuff in there at all... I now
> think version is *almost* useless. Could probably use
> this for operating system versions too, putting the
> common components in a shared file.
>

The fact that everyone has their own work-around, and everyone has a
DIFFERENT work around is hard evidence that version() is insufficient, and
the current design is making D code WORSE.
Even Walter describes and supports the work-arounds to use in his poses
from years ago.

I can see absolutely no evidence that performing logical expressions on versions is not required by any cross platform applications, including phobos! However now, instead of expressing the logic in a concise and familiar fashion, you have to try and decode each individuals own personal work-around scheme, at the expense of 10s of lines of really ugly spaghetti, and for absolutely no benefit.

There is hard evidence people can't work without version logic, so why continue to deny it?

Using '} else {' as a substitute for ! for example, you're STILL typing
'!', you're just writing it in the ugliest and least intuitive way
possible. Are people REALLY more likely to mis-read/misunderstand the '!'
in the expression than miss the obscure 'else' statement to fake the same
effect?
Using 'version(A) version(B)' as a substitute for &&... it's still &&,
except it's way longer, and it's certainly not as clear that you're really
performing a boolean &&. Why not just write what it is?
And ||, the MOST common operation to want to perform... let's not mention
the work around, it's clearly the worst. Suffice to say, you're still
producing OR logic, but again, writing it in a really archaic fashion.

People ARE writing these logical constructs whether they use a clear logical expressions or not... why not just let them write it between the parentheses in a clear and concise manner, than scatter and obscure the logic across 10 lines?