patch 8.0.0251: not easy to select Python 2 or 3v8.0.0251

Problem:    It is not so easy to write a script that works with both Python 2
            and Python 3, even when the Python code works with both.
Solution:   Add 'pyxversion', :pyx, etc. (Marc Weber, Ken Takata)

1 files changed, 28 insertions, 0 deletions

diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index a9a0cc4835..4e9490223b 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -5789,6 +5789,34 @@ A jump table for the options with a short description can be found at |Q_op|.
 	This option cannot be set from a |modeline| or in the |sandbox|, for
 	security reasons.
 
+						*'pyxversion'* *'pyx'*
+'pyxversion' 'pyx'	number	(default depends on the build)
+			global
+			{not in Vi}
+			{only available when compiled with the |+python| or
+			the |+python3| feature}
+	Specifies the python version used for pyx* functions and commands
+	|python_x|.  The default value is as follows:
+
+		Compiled with		     Default ~
+		|+python| and |+python3|	0
+		only |+python|			2
+		only |+python3|			3
+
+	Available values are 0, 2 and 3.
+	If 'pyxversion' is 0, it is set to 2 or 3 after the first execution of
+	any python2/3 commands or functions.  E.g. `:py` sets to 2, and `:py3`
+	sets to 3. `:pyx` sets it to 3 if Python 3 is available, otherwise sets
+	to 2 if Python 2 is available.
+	See also: |has-pythonx|
+
+	If Vim is compiled with only |+python| or |+python3| setting
+	'pyxversion' has no effect.  The pyx* functions and commands are
+	always the same as the compiled version.
+
+	This option cannot be set from a |modeline| or in the |sandbox|, for
+	security reasons.
+
 						*'quoteescape'* *'qe'*
 'quoteescape' 'qe'	string	(default "\")
 			local to buffer