[Omake] Re: Building in subdirectories and variant builds revisited

[Aleksey Nogin]

On 19.06.2007 01:51, Jesper Eskilson wrote:

> It would be unfortunate if support for out-of-source builds was left
> out just because it can't be implemented 100% correctly for 100% of
> every tool out there. I think that would be the wrong approach.

This is not what happened and we are working on addressing this. One of 
the primary design goals of OMake was to compile the OCaml code 
correctly (although we definitely want to be able to compile other 
languages as well). With OCaml, there was a problem of ocamldep, which, 
as I said in my previous email, was doing things wrong (at least from 
the perspective of out-of-tree builds).

We finally addressed the ocamldep limitations:
  - OCaml 3.10 (released just about a month ago) includes a version of 
ocamldep that can be asked ("ocamldep -modules") to dump a raw list of 
module dependencies - an option that was requested by Jason specifically 
to allow tools like OMake to do things right.
  - Even before OCaml 3.10 was released, we added an experimental 
capability of using the "ocamldep -modules" output to produce a more 
accurate list of dependencies - this was first included in OMake 0.9.8 
(December 2006). This brought up a number of interesting issues (such as 
the need for OMake to detect case-insensitive filesystems, e.g. on Mac 
OS X). Those were also resolved and finally just a little while ago 
(OMake 0.9.8.3, released June 1, 2007) we made using the "ocamldep 
-modules" the default mode of compiling OCaml code under OMake.

Now that there is some hope of doing out-of-tree builds for OCaml in a 
nice "generic" way, we can (and will!) explore this issue further. IMO 
the next step in that direction would be to get OMake to compile itself 
in an out-of-source-tree variant build fashion. This should give us a 
much better handle on the problem.

Aleksey

-- 
Aleksey Nogin, Research Scientist
Advanced Technologies Department, Information & System Sciences Lab
HRL Laboratories, LLC, Malibu, CA