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, 45 insertions, 46 deletions

diff --git a/Library/Formula/pygtk.rb b/Library/Formula/pygtk.rb
index 2d40f9533..2aa53b22e 100644
--- a/Library/Formula/pygtk.rb
+++ b/Library/Formula/pygtk.rb
@@ -6,6 +6,7 @@ class Pygtk < Formula
   sha1 '344e6a32a5e8c7e0aaeb807e0636a163095231c2'
 
   depends_on 'pkg-config' => :build
+  depends_on :python
   depends_on :x11
   depends_on 'glib'
   depends_on 'gtk+'
@@ -18,11 +19,13 @@ class Pygtk < Formula
   option 'glade', 'Python bindigs for glade. (to `import gtk.glade`)'
 
   def install
-    ENV.append 'CFLAGS', '-ObjC'
-    ENV.universal_binary if build.universal?
-    system "./configure", "--disable-dependency-tracking",
-                          "--prefix=#{prefix}"
-    system "make install"
+    python do
+      ENV.append 'CFLAGS', '-ObjC'
+      ENV.universal_binary if build.universal?
+      system "./configure", "--disable-dependency-tracking",
+                            "--prefix=#{prefix}"
+      system "make install"
+    end
 
     # Fixing the pkgconfig file to find codegen, because it was moved from
     # pygtk to pygobject. But our pkgfiles point into the cellar and in the
@@ -30,55 +33,51 @@ class Pygtk < Formula
     inreplace lib/'pkgconfig/pygtk-2.0.pc', 'codegendir=${datadir}/pygobject/2.0/codegen', "codegendir=#{HOMEBREW_PREFIX}/share/pygobject/2.0/codegen"
   end
 
-  def caveats; <<-EOS.undent
-    For non-Homebrew Python, you need to amend your PYTHONPATH like so:
-      export PYTHONPATH=#{HOMEBREW_PREFIX}/lib/#{which_python}/site-packages:$PYTHONPATH
-    EOS
-  end
-
-  def which_python
-    "python" + `python -c 'import sys;print(sys.version[:3])'`.strip
+  def caveats
+    python.standard_caveats if python
   end
 
   test do
-    (testpath/'test.py').write <<-EOS.undent
-      #!/usr/bin/env python
-      import pygtk
-      pygtk.require('2.0')
-      import gtk
+    python do
+      (testpath/'test.py').write <<-EOS.undent
+        #!/usr/bin/env python
+        import pygtk
+        pygtk.require('2.0')
+        import gtk
 
-      class HelloWorld(object):
-          def hello(self, widget, data=None):
-              print "Hello World"
+        class HelloWorld(object):
+            def hello(self, widget, data=None):
+                print "Hello World"
 
-          def delete_event(self, widget, event, data=None):
-              print "delete event occurred"
-              return False
+            def delete_event(self, widget, event, data=None):
+                print "delete event occurred"
+                return False
 
-          def destroy(self, widget, data=None):
-              print "destroy signal occurred"
-              gtk.main_quit()
+            def destroy(self, widget, data=None):
+                print "destroy signal occurred"
+                gtk.main_quit()
 
-          def __init__(self):
-              self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)
-              self.window.connect("delete_event", self.delete_event)
-              self.window.connect("destroy", self.destroy)
-              self.window.set_border_width(10)
-              self.button = gtk.Button("Hello World")
-              self.button.connect("clicked", self.hello, None)
-              self.button.connect_object("clicked", gtk.Widget.destroy, self.window)
-              self.window.add(self.button)
-              self.button.show()
-              self.window.show()
+            def __init__(self):
+                self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)
+                self.window.connect("delete_event", self.delete_event)
+                self.window.connect("destroy", self.destroy)
+                self.window.set_border_width(10)
+                self.button = gtk.Button("Hello World")
+                self.button.connect("clicked", self.hello, None)
+                self.button.connect_object("clicked", gtk.Widget.destroy, self.window)
+                self.window.add(self.button)
+                self.button.show()
+                self.window.show()
 
-          def main(self):
-              gtk.main()
+            def main(self):
+                gtk.main()
 
-      if __name__ == "__main__":
-          hello = HelloWorld()
-          hello.main()
-    EOS
-    chmod 0755, 'test.py'
-    system "./test.py"
+        if __name__ == "__main__":
+            hello = HelloWorld()
+            hello.main()
+      EOS
+      chmod 0755, 'test.py'
+      system "./test.py"
+    end
   end
 end