version(D_Version2)

[Bill Baxter]

Derek Parnell wrote:
> On Wed, 12 Mar 2008 17:56:49 +0900, Bill Baxter wrote:
> 
>> I just resorted to this in something I was doing the other day:
>>
>>  > gcc -C -E -xc file_in.d | sed -e "s/^#/#line/" > file.d
>>  > dmd file.d
> 
> I have no idea what that means. 
> 
> I don't use gcc and I run D in a Windows environment. I use Linux daily at
> the office because that's I develop software for (but not in C/C++) so I
> understand the 'sed' part is, but what's gcc doing?

It's what the others said.

gcc -E just runs the preprocessor
-C says to keep the comments instead of stripping them
-xc says to pretend the following file is C code despite the extension.

The preprocessor spits out line directives like

   # 1 "somefile"

In D those are supposed to be

   #line 1 "somefile"

So the sed thing makes that change.  The regexp there is pretty dumb, 
though.  Really I guess you need a parser that can understand quoted 
strings to do the job 100% properly.  But it was enough for my case.

--bb