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, 32 insertions, 33 deletions

diff --git a/Library/Formula/shiboken.rb b/Library/Formula/shiboken.rb
index 29950a0b4..fe5128d74 100644
--- a/Library/Formula/shiboken.rb
+++ b/Library/Formula/shiboken.rb
@@ -7,48 +7,47 @@ class Shiboken < Formula
   sha1 '2ffe9d47a3f536840ed9d7eff766a53040bb2a2e'
 
   depends_on 'cmake' => :build
+  depends_on :python => :recommended
+  depends_on :python3 => :optional
   depends_on 'qt'
 
   def install
     # Building the tests also runs them. Not building and running tests cuts
-    # install time in half.  As of 1.1.1 the install fails unless you do an
+    # install time in half. As of 1.1.1 the install fails unless you do an
     # out of tree build and put the source dir last in the args.
-    mkdir 'macbuild' do
-      args = std_cmake_args + %W[
-        -DBUILD_TESTS=OFF
-      ]
-
-
-      python_prefix = `python-config --prefix`.strip
-      # Python is actually a library. The libpythonX.Y.dylib points to this lib, too.
-      if File.exist? "#{python_prefix}/Python"
-        # Python was compiled with --framework:
-        args << "-DPYTHON_LIBRARY='#{python_prefix}/Python'"
-        if !MacOS::CLT.installed? and python_prefix.start_with? '/System/Library'
-          # For Xcode-only systems, the headers of system's python are inside of Xcode
-          args << "-DPYTHON_INCLUDE_DIR='#{MacOS.sdk_path}/System/Library/Frameworks/Python.framework/Versions/2.7/Headers'"
-        else
-          args << "-DPYTHON_INCLUDE_DIR='#{python_prefix}/Headers'"
-        end
-      else
-        python_version = `python-config --libs`.match('-lpython(\d+\.\d+)').captures.at(0)
-        python_lib = "#{python_prefix}/lib/libpython#{python_version}"
-        if File.exists? "#{python_lib}.a"
-          args << "-DPYTHON_LIBRARY='#{python_lib}.a'"
-        else
-          args << "-DPYTHON_LIBRARY='#{python_lib}.dylib'"
-        end
-        args << "-DPYTHON_INCLUDE_DIR='#{python_prefix}/include/#{which_python}'"
+    python do
+      # This block will be run for each python (2.x and 3.x if requested)!
+      mkdir "macbuild#{python.if3then3}" do
+        args = std_cmake_args
+        args << "-DBUILD_TESTS=OFF"
+        # For Xcode-only systems, the headers of system's python are inside of Xcode:
+        args << "-DPYTHON#{python.if3then3}_INCLUDE_DIR='#{python.incdir}'"
+        # Cmake picks up the system's python dylib, even if we have a brewed one:
+        args << "-DPYTHON#{python.if3then3}_LIBRARY='#{python.libdir}/lib#{python.xy}.dylib'"
+        args << "-DUSE_PYTHON3=ON" if python3
+        args << '..'
+        system 'cmake', *args
+        system "make install"
+        # To support 2.x and 3.x in parallel, we have to rename shiboken.pc at first
+        mv lib/'pkgconfig/shiboken.pc', lib/"pkgconfig/shiboken-py#{python.version.major}.pc"
       end
+    end
+    # Rename shiboken-py2.pc back to the default shiboken.pc
+    mv lib/'pkgconfig/shiboken-py2.pc', lib/'pkgconfig/shiboken.pc' if python2
+  end
 
-
-      args << '..'
-      system 'cmake', *args
-      system "make install"
+  def caveats
+    if python3
+      <<-EOS.undent
+        If you build software that uses the pkgconfig file, and you want
+        shiboken with Python 3.x support: Please, instead of 'shiboken.pc', use:
+          #{HOMEBREW_PREFIX}/lib/pkgconfig/shiboken-py3.pc
+      EOS
     end
   end
 
-  def which_python
-    "python" + `python -c 'import sys;print(sys.version[:3])'`.strip
+  def test
+    system 'python', "-c", "import shiboken" if Tab.for_formula('Shiboken').with? 'python'
+    system 'python3', "-c", "import shiboken" if Tab.for_formula('Shiboken').with? 'python3'
   end
 end