On Thursday, 26 April 2012 at 12:37:44 UTC, Steven Schveighoffer
wrote:
On Thu, 26 Apr 2012 06:32:58 -0400, James Miller
<[email protected]> wrote:
On Thursday, 26 April 2012 at 10:20:37 UTC, Jonathan M Davis
wrote:
On Thursday, April 26, 2012 12:09:19 James Miller wrote:
which pretty much makes them completely useless unless
you only use the built-in versions.
That's not true at all. It just means that versions are
either useful for
something within a module or they're intended for your
program as a whole and
passed on the command line (e.g. StdDdoc is used by Phobos,
and it's not
standard at all; the makefile adds it to the list of compiler
flags). But yes,
it's true that if you want to define a version in one module
which affects
another, you can't do it.
Is there any reason for that limitation? Seems like an
arbitrary limit to me.
The library I am binding to uses ifdefs to let the compiler
see the appropriate declarations in the header files. It would
be nice in general for D to be able to mimic that capability,
as it means you can have a "configuration" file with a list of
specs that can be generated at build-time by something like
autoconf.
No, it would not be nice, it would be horrible. C's
preprocessor is one of the main reasons I sought out something
like D. The fact that you can include files in a different
order and get a completely different result is not conducive to
understanding code or keeping code sane.
The correct thing to use for something like this is enums and
static ifs. They work because enums are fully qualified within
the module they are defined, and you can't define and use the
same unqualified enums in multiple places.
[snip]
These kinds of decoupled effects are what kills me when I ever
read a heavily #ifdef'd header file.
versions should be defined for the *entire program*, not just
for certain files. And if they are defined just for certain
files, define them in the file itself.
-Steve
I didn't think about it like that, thanks. I'm planning on just
using enums and static ifs in this case now, since it certainly
makes more sense and I can achieve the same effect.
Thanks all
--
James Miller
