Big problem with Small programs

[Todor Totev]

> Walter Bright wrote:
>>   Try using enums instead of const variables, they don't take up any  
>> space in the object file.
>
> Thanks, but that makes only a dent in the overhead.


Actually using enums instead of consts have a very nice side effect.
Consider this declaration from win32:

HANDLE CreateFileW(LPCWSTR, DWORD, DWORD, LPSECURITY_ATTRIBUTES, DWORD,  
DWORD, HANDLE);

Now, which invocation is correct?

CreateFile("a", OPEN_EXISTING, FILE_SHARE_READ, null, GENERIC_READ ...)
or
CreateFile("a", OPEN_EXISTING, GENERIC_READ, null, FILE_SHARE_READ ...)
or even
CreateFile("a", GENERIC_READ, OPEN_EXISTING, null, FILE_SHARE_READ ...)?

The compiler happily accepts all of them.

Using enums, we have:

enum FILE_SHARE {
   READ  = 1,
   WRITE = 2,
   BOTH  = READ | WRITE
}

enum DISPOSITION {
   CREATE_ALWAYS = 1,
   OPEN_EXISTING = 2
}

void CreateFile(char[] fileName, DISPOSITION disposition, FILE_SHARE  
share) {}

int main() {
   // compiler allows unknown flags
   CreateFile("filename", cast(DISPOSITION)4, FILE_SHARE.READ);

   // when we swap the arguments by mistake
   CreateFile("filename", FILE_SHARE.READ, DISPOSITION.CREATE_ALWAYS);

   return 0;
}

This way if I make an error the compiler will very helpfully tell me
what exactly is happening. Consider: CreateFont has 14 parameters,
if the IDE does not help me i'd make an error when I use it, trust me

On the other hand, when a new version of Windows come with expanded options
I can just use the new numbers without breaking anything while the d  
package is
updated.

The dotnet framework uses enums and I really like the idea.

Regards,
Todor