Python 2.x and 3.x support

New `depends_on :python` Dependency.
New `depends_on :python3` Dependency.

To avoid having multiple formulae with endings -py2 and -py3,
we will handle support for different pythons (2.x vs. 3.x)
in the same formula.
Further brewed vs. external python will be transparently supported.

The formula also gets a new object `python`, which is false if
no Python is available or the user has disabled it. Otherwise
it is defined and provides several support methods:

python.site_packages # the site-packages in the formula's Cellar
python.global_site_packages
python.binary # the full path to the python binary
python.prefix
python.version
python.version.major
python.version.minor
python.xy # => e.g. "python2.7"
python.incdir # includes of python
python.libdir # the python dylib library
python.pkg_config_path # used internally by brew
python.from_osx?
python.framework?
python.universal?
python.pypy?
python.standard_caveats # Text to set PYTHONPATH for python.from_osx?
python.if3then3 # => "" for 2.x and to "3" for 3.x.

Further, to avoid code duplication, `python` takes an optional
block that is run twice if the formula defines depends_on
:python AND :python3.

python do
  system python, 'setup.py', "--prefix=#{prefix}"
end

Read more in the Homebrew wiki.

1 files changed, 10 insertions, 6 deletions

diff --git a/Library/Formula/bup.rb b/Library/Formula/bup.rb
index 3fe5f39b3..1592ada16 100644
--- a/Library/Formula/bup.rb
+++ b/Library/Formula/bup.rb
@@ -1,14 +1,16 @@
 require 'formula'
 
 class Bup < Formula
-  homepage 'https://github.com/apenwarr/bup'
-  url 'https://github.com/apenwarr/bup/archive/bup-0.25-rc1.tar.gz'
+  homepage 'https://github.com/bup/bup'
+  url 'https://github.com/bup/bup/archive/bup-0.25-rc1.tar.gz'
   sha1 'b88bd38d6f00a646faf0bd1f561595ebc0e55b30'
 
-  head 'https://github.com/apenwarr/bup.git', :branch => 'master'
+  head 'https://github.com/bup/bup.git', :branch => 'master'
 
   option "run-tests", "Run unit tests after compilation"
 
+  depends_on :python
+
   # patch to make the `--prefix` parameter work
   # found at https://github.com/apenwarr/bup/pull/5
   def patches
@@ -16,9 +18,11 @@ class Bup < Formula
   end
 
   def install
-    ENV['PATH'] = '/usr/bin:' + ENV['PATH'] # make sure we Sytem Python
-    system "./configure", "--prefix=#{prefix}"
-    system "make"
+    python do
+      ohai ENV['PATH']
+      system "./configure", "--prefix=#{prefix}"
+      system "make"
+    end
     system "make test" if build.include? "run-tests"
     system "make install"
   end