From: Jim Weirich <jim@...>
Date: 2004-08-28T08:43:24+09:00
Subject: Re: Rake Bug

Jim Weirich wrote:

>>* Jim Weirich <jim@weirichhouse.org> [2004-08-28 05:11:24 +0900]:
>>>If you want something to be dependent upon the rakefile, then declare
>>>the Rakefile in the dependencies.

> jim@freeze.org said:
>>Good idea. So, does the following look like a good way to do this?
[... example elided ...]

Here's what I did.  I have a small project of two C files (main.c and 
hello.c) and one header file (hello.h).  Here is the rakefile I used ...

-- BEGIN Rakefile ---------------------------------------------------
# -*- ruby -*-

require 'rake/clean'

CC = 'gcc'
LD = CC

PROG = 'hi'
SRC = FileList['*.c']
HDR = FileList['*.h']
OBJ = SRC.sub(/\.c$/, '.o')

CLOBBER.include(PROG, *OBJ)

task :default => [:compile]
task :compile => [PROG]

file PROG => OBJ
OBJ.each do |obj|
   header = obj.sub(/\.o$/, '.h')
   file obj => [header] if File.exists?(header)
   file obj => ['Rakefile']
end

rule '.o' => ['.c'] do |t|
   sh "#{CC} #{t.source} -c -o #{t.name}"
end

rule(/^#{PROG}$/ => lambda { |src| OBJ.first } ) do |t|
   sh "#{LD} #{OBJ} -o #{t.name}"
end
-- END --------------------------------------------------------------

And here's an example session...

$ rake clobber
(in /home/jim/pgm/ruby/rakemisc/cstuff)
rm -r hi
rm -r hello.o
rm -r main.o
$
$ rake compile
(in /home/jim/pgm/ruby/rakemisc/cstuff)
gcc hello.c -c -o hello.o
gcc main.c -c -o main.o
gcc hello.o main.o -o hi
$
$ rake compile
(in /home/jim/pgm/ruby/rakemisc/cstuff)
$
$ touch Rakefile
$ rake compile
(in /home/jim/pgm/ruby/rakemisc/cstuff)
gcc hello.c -c -o hello.o
gcc main.c -c -o main.o
gcc hello.o main.o -o hi
$
$ rake compile
(in /home/jim/pgm/ruby/rakemisc/cstuff)
$

-- 
-- Jim Weirich    jim@weirichhouse.org     http://onestepback.org
-----------------------------------------------------------------
"Beware of bugs in the above code; I have only proved it correct,
not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)