Vimrc python37 (#739)

* Use Python 3.7 from python.org if installed

* Use Python from MacPorts after Homebrew if installed

* Added requested comments and Python2.7 from python.org detection

Author: eirnym

src/MacVim/vimrc

@@ -15,23 +15,39 @@ set backspace+=indent,eol,start
 set langmenu=none
 
 " Python2
-" MacVim uses Homebrew python2 if installed, otherwise configured one
+" MacVim is configured by default to use the pre-installed System python2
+" version. However, following code tries to find a Homebrew, MacPorts or
+" an installation from python.org:
 if exists("&pythondll") && exists("&pythonhome")
-  if filereadable("/usr/local/Frameworks/Python.framework/Versions/2.7/Python")
+  if filereadable("/usr/local/Library/Frameworks/Python.framework/Versions/2.7/Python")
     " Homebrew python 2.7
     set pythondll=/usr/local/Frameworks/Python.framework/Versions/2.7/Python
     set pythonhome=/usr/local/Frameworks/Python.framework/Versions/2.7
+  elseif filereadable("/opt/local/Library/Frameworks/Python.framework/Versions/2.7/Python")
+    " MacPorts python 2.7
+    set pythondll=/opt/local/Library/Frameworks/Python.framework/Versions/2.7/Python
+    set pythonhome=/opt/local/Library/Frameworks/Python.framework/Versions/2.7
+  elseif filereadable("/Library/Frameworks/Python.framework/Versions/2.7/Python")
+    " https://www.python.org/downloads/mac-osx/
+    set pythonthreedll=/Library/Frameworks/Python.framework/Versions/2.7/Python
+    set pythonthreehome=/Library/Frameworks/Python.framework/Versions/2.7
   endif
 endif
 
 " Python3
-" MacVim uses Homebrew python3 if installed, next try to use python.org binary
+" MacVim is configured by default to use Homebrew python3 version
+" If this cannot be found, following code tries to find a MacPorts
+" or an installation from python.org:
 if exists("&pythonthreedll") && exists("&pythonthreehome") &&
       \ !filereadable(&pythonthreedll)
-  if filereadable("/Library/Frameworks/Python.framework/Versions/3.6/Python")
+  if filereadable("/opt/local/Library/Frameworks/Python.framework/Versions/3.7/Python")
+    " MacPorts python 3.7
+    set pythonthreedll=/opt/local/Library/Frameworks/Python.framework/Versions/3.7/Python
+    set pythonthreehome=/opt/local/Library/Frameworks/Python.framework/Versions/3.7
+  elseif filereadable("/Library/Frameworks/Python.framework/Versions/3.7/Python")
     " https://www.python.org/downloads/mac-osx/
-    set pythonthreedll=/Library/Frameworks/Python.framework/Versions/3.6/Python
-    set pythonthreehome=/Library/Frameworks/Python.framework/Versions/3.6
+    set pythonthreedll=/Library/Frameworks/Python.framework/Versions/3.7/Python
+    set pythonthreehome=/Library/Frameworks/Python.framework/Versions/3.7
   endif
 endif