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digitalmars.D.learn - Is this a bug or illegal code?

reply "safety0ff" <safety0ff.dev gmail.com> writes:
//******* CODE **********
mixin("version = foo;");
version(foo)
{
void main(){}	
}
//****** END CODE *******
If it's illegal in D, what is the reason & where is documented?

The reason I was considering such a construct is the following:
Some C libraries have an associated "config.h" header that gets 
generated when it is compiled.
I was thinking it may be possible to parse these config.h files 
at compile time (using text import) and convert some of the 
#define's into "version = foo;"

It wouldn't do any favors for compile times, but it would save on 
having an extra step in the build process to convert config.h to 
config.d.
May 29 2014
parent reply "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Thu, 29 May 2014 10:45:28 -0400, safety0ff <safety0ff.dev gmail.com>  
wrote:


 //******* CODE **********
 mixin("version = foo;");
 version(foo)
 {
 void main(){}	
 }
 //****** END CODE *******
 If it's illegal in D, what is the reason & where is documented?

 The reason I was considering such a construct is the following:
 Some C libraries have an associated "config.h" header that gets  
 generated when it is compiled.
 I was thinking it may be possible to parse these config.h files at  
 compile time (using text import) and convert some of the #define's into  
 "version = foo;"


Even if that is valid code, you are much better off using enums and static  
if.

enum includeSomeFeature = ...

static if(includeSomeFeature)
{
  ...
}

These work much more like #defines, and can be seen outside the module.

-Steve
May 29 2014
parent "safety0ff" <safety0ff.dev gmail.com> writes:
On Thursday, 29 May 2014 at 15:02:48 UTC, Steven Schveighoffer 
wrote:

 Even if that is valid code, you are much better off using enums 
 and static if.

 enum includeSomeFeature = ...

 static if(includeSomeFeature)
 {
  ...
 }

 These work much more like #defines, and can be seen outside the 
 module.

 -Steve


Thanks, the following works:
mixin("enum hasFoo = true;");
static if(hasFoo)
{
void main(){}	
}
May 29 2014