[Omake] .PHONY rules in subdirs

[Jonathan Roewen]

To follow on from this discussion, is it possible to extend this to
say have an implicit rule that can find all targets created by a phony
rule (e.g. all), and rm -f those?

That'd be great for a 'distclean' kind of rule =)

Jonathan

On 3/30/07, Aleksey Nogin <anogin at hrl.com> wrote:
> Hi Tom,
>
> Thanks a lot for a very good question. Let me first go over some of the
> details before answering it.
>
> On 28.03.2007 18:44, Tom Murray wrote:
>
> > I'm trying to define a set of default (phony) targets to be active in
> > every subdirectory of my project, a la automake. For example, I want
> > "omake clean" to execute some general cleaning code, and I want to be
> > able to define this once in the root, and not have to copy the
> > definition to subdirectories.
>
> Note that is it easy to define a set of phony _targets_ that would then
> exist in every project directory - this is what the hierarchy of the
> .PHONY targets is supposed to give you if you use ".PHONY: clean" in
> your top-level OMakefile (or OMakeroot) before any of the .SUBDIRS lines.
>
> What is harder, as you found out, is to define some "universal" _rules_
> for those targets.
>
> > I find
> > the current implementation of this a bit strange: When I type "omake
> > clean" in a subdirectory, it is clearly using the top-level clean rule
> > in some way, because the invocation does not fail.
>
> Here, the "clean" target in the subdirectory is known to be phony, but
> there are no rules for it (As I understand what you are trying to do,
> you only have a "clean: ..." rule for the clean target in the project
> root, but no rules in the subdirectory). In general, OMake is happy to
> accept any number of rules for phony targets, including not doing
> anything in case there are no rules at all. So this is what happens -
> the target is known to be phony, there are no rules for it, it has no
> dependencies, so OMake does not do anything.
>
> > Is there some other mechanism I should be using to achieve what I want
> > to do?
> [...]
> > Must I call an "installMySpecialTargets()"
> > function at the end of each OMakefile? Please say it ain't so!
>
> While using some sort of "InstallMyGlobalRules()" call in every
> subdirectory is indeed an option, I completely agree that it is not a
> very good one.
>
> The best approach would probably be to use an implicit rule that would
> then propagate to every subdirectory:
>
> --------
> .PHONY: clean
>
> clean%:
>   rm -f *$(EXT_OBJ) *$(EXT_LIB)
>
> .SUBDIRS: ...
> --------
>
> In current OMake, there are two imperfections w.r.t. this approach:
>
> - You can not define an implicit rule without having a pattern with a
> wildcard in it, so you end up having to use "clean%" (or "%clean", or
> some other variation), which might accidentally match something you did
> not intend to match. I've filed
> http://bugzilla.metaprl.org/show_bug.cgi?id=658 about this.
>
> - If a subdirectory defines its own clean rule (whether implicit or
> not), the existing one will get shadowed and not executed for that
> subdirectory. Depending on the situation, you might be interested in
> keeping both. I've filed http://bugzilla.metaprl.org/show_bug.cgi?id=659
> discussing this.
>
> P.S. One suggestion would be to use something like
>
> --------
> .PHONY: clean
>
> EXTRA_CLEANING =
>
> clean%:
>   rm -f *$(EXT_OBJ) *$(EXT_LIB) $(EXTRA_CLEANING)
>
> .SUBDIRS: ...
> --------
>
> This way any subdirectories can add their own stuff to the
> EXTRA_CLEANING variable.
>
> Aleksey
>
> --
> Aleksey Nogin, Research Staff Member
> Advanced Technologies Department, Information & System Sciences Lab
> HRL Laboratories, LLC, Malibu, CA
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