From: Joe Van Dyk <joevandyk@...>
Date: 2005-07-16T05:22:53+09:00
Subject: Re: rake question

On 7/15/05, Olaf Klischat <klischat@cs.tu-berlin.de> wrote:
> Joe Van Dyk <joevandyk@gmail.com> writes:
> 
> > On 7/14/05, Joe Van Dyk <joevandyk@gmail.com> wrote:
> >> rule '.o' => ['.c'] do |t|
> >>     sh "cc #{t.source} -c -o #{t.name}"
> >> end
> >>
> >> But, when I change the .c source file, it doesn't get compiled again.
> >> Why is that?
> >>
> >> Example:
> >>
> >> PowerBook:~/that_stuff/test1 joe$ ls
> >> Rakefile                another_test.h          test.cpp
> >> another_test.cpp        main.cpp                test.h
> >>
> >> PowerBook:~/that_stuff/test1 joe$ cat Rakefile
> >> require 'rake/clean'
> >> CLEAN.include '*.o', 'test'
> >> CPP_SOURCE = FileList['*.cpp']
> >> OBJS = CPP_SOURCE.ext 'o'
> >>
> >> task :default => :run
> >> task :run => "test" do
> >>   sh "./test"
> >> end
> >> file "test" => OBJS do
> >>   sh "g++ -o test #{OBJS}"
> >> end
> >> rule '.o' => '.cpp' do |t|
> >>   sh "g++ -c -o #{t.name} #{t.source}"
> >> end
> >> CPP_SOURCE.each do |cpp|
> >>   headers = File.read(cpp).scan(/^#include "(.+)"/)
> >>   task cpp => headers
> >> end
> >>
> >> PowerBook:~/that_stuff/test1 joe$ rake
> >> (in /Users/joe/that_stuff/test1)
> >> g++ -c -o another_test.o another_test.cpp
> >> g++ -c -o main.o main.cpp
> >> g++ -c -o test.o test.cpp
> >> g++ -o test another_test.o main.o test.o
> >> ./test
> >> Whassup
> >> what's up!
> >>
> >>
> >> PowerBook:~/that_stuff/test1 joe$ touch main.cpp
> >> PowerBook:~/that_stuff/test1 joe$ rake
> >> (in /Users/joe/that_stuff/test1)
> >> ./test
> >> Whassup
> >> what's up!
> >>
> >> It should've recompiled main.cpp and relinked everything, right?
> >
> > When I comment out
> >> CPP_SOURCE.each do |cpp|
> >>   headers = File.read(cpp).scan(/^#include "(.+)"/)
> >>   task cpp => headers
> >> end
> >
> > Then it works as expected.  So, "task cpp => headers" is the culprit.
> > But I'm still not sure why it breaks everything else.
> 
> Well, AFAICS it happens to be the case that, when you have defined an
> explicit task like foo.cpp, then rules matching the task name won't be
> considered when computing the dependencies of the task. See Task.[] in
> rake.rb for details -- given a task name, it just returns the task if
> it is defined, without considering additional dependencies imposed by
> rules matching the task's name.
> 
> This could be considered unfortunate behaviour or a bug :) A related
> problem I had is that rules can only define a single prerequisite,
> which seems like a quite arbitrary restriction to me.

Hm.  So, are there any work arounds, other than to rebuild the entire
thing when a .h file changes?

What I'm trying to do is become a better software developer.  So, I've
got a couple C and C++ books.  I want to do the examples in them.  So
I'll have directories like
/
/c/
/c/problem_1_1/
/c/problem_1_2/
/c/problem_1_2/main.c
/c/problem_1_2/foo.c
/c/problem_1_2/foo.h
/c/problem_1_2/test_foo.c
/c++/


And so on.  I want a Rake file that will go into the directory
structure, compile all the code, compile all the test code, and run
the tests.  Then I want it to create syntax-highlighted webpages that
shows for each example the code and the output and the tests, and then
posts them to a website where I can get comments on them.

Perhaps I'll have separate build directories (so I can build and test
the code on Windows, Linux, FreeBSD, and OS X)..

So, I'm looking for help for that.

Thanks!
Joe