From: Stefan Lang <langstefan@...>
Date: 2005-04-28T09:30:08+09:00
Subject: Re: Rake help required

On Thursday 28 April 2005 01:38, Mark Probert wrote:
> Hi ..
>
> I am not sure how to create a set of Rake rules to do the following.  Can
> anyone prove assistance?
>
> Structure:
>
>   Rakefile
>   foo
>   src_a/
>     a_1.c
>     a_2.c
>   src_b/
>     b_1.c
>     b_2.c
>   obj/
>     a_1.o
>     a_2.o
>     b_1.o
>     b_2.o
>     libfoo.a  ("ar cr libfoo.a obj/*.c; ranlib libfoo.a")
>
> I would like to have a single target
>
>   $ rake build
>
> That would create the .o and the lib, then link them into the executable. 
> I can do this if everything is in the root directory but I am finding
> defining the objects trickier.
>
> I'd rather avoid explicitly putting the directory name in the source list,
> like
>
>  SRC_A = ["src_a/a_1.c" ...]
>
> Regards,

An Rantfile that does this job could look like:

    desc "Build foo."
    file :foo => "obj/libfoo.a" do |t|
        # adjust...
        sys "cc -o #{t.name} #{t.source}"
    end
    
    o_files = sys["**/*.c"].map { |f| "obj/" + File.basename(f).sub_ext("o") }
    file "obj/libfoo.a" => o_files do |t|
        sys "ar cr #{t.name} #{t.prerequisites.arglist}"
        sys "ranlib #{t.name}"
    end
    
    o_to_c = lambda { |t|
        t =~ /^obj\/([^_])_/
        "src_#{$1}/#{File.basename(t)}".sub_ext "c"
    }
    gen Rule, :o => o_to_c do |t|
        sys "cc -c -o #{t.name} #{t.source}"
    end

When invoking rant it will build foo, as its the first task:
    % rant

Stefan