Re: Fwd: Suggestion about derived files and commands

[Wayne Scott]

From: Doug Warner x81804 <address@hidden>
> I wrote a little Extensions module that tried to make CONS aware of our
> SCCS repository.  Unfortunately, it didn't work very well, because CONS
> determined that I had modified my working copies outside of CONS and
> decided to rebuild them from the pristine SCCS repository.  I made the
> source files depend on the SCCS history file, which obviously doesn't work
> when it comes to version control.  CONS may not need to be aware of
> particular version control systems, but it may need to be aware that
> version control differs from compiling sources to objects.

I agree.  This is the problem.  You can't just use a build rule like
Make can do because Cons is too clever.  It can't stand people messing
with derived files.

I can think of two ways to solve this problem.
  
  * Add some sort of "weak" rules that will build a file if it doesn't
    exist, but if it does exist it treat it like another source file.

  * Have the ability to overload CONS's "file exists" primitive.  So
    that when cons looks for a file in a directory if it is not found
    we can quickly query the revision system.

I would like Cons to work great with Bitkeeper. ;-)

-Wayne