Add rsplit method for str and unicode builtin types.
SF feature request #801847.
Original patch is written by Sean Reifschneider.
diff --git a/Doc/lib/libstdtypes.tex b/Doc/lib/libstdtypes.tex
index 7feda60..4ce6ec5 100644
--- a/Doc/lib/libstdtypes.tex
+++ b/Doc/lib/libstdtypes.tex
@@ -694,6 +694,24 @@
\versionchanged[Support for the \var{fillchar} argument]{2.4}
\end{methoddesc}
+\begin{methoddesc}[string]{rsplit}{\optional{, sep\optional{, maxsplit}}}
+Return a list of the words of the string, scanning the string from
+the end working forward. The resulting list of words is in the
+same order as \function{split()}. If the optional second argument
+\var{sep} is absent or \code{None}, the words are separated by
+arbitrary strings of whitespace characters (space, tab, newline,
+return, formfeed). If the second argument \var{sep} is present and
+not \code{None}, it specifies a string to be used as the word
+separator. The returned list will then have one more item than the
+number of non-overlapping occurrences of the separator in the string.
+The optional third argument \var{maxsplit} defaults to 0. If it
+is nonzero, at most \var{maxsplit} number of splits occur, and the
+remainder of the string is returned as the first element of the
+list (thus, the list will have at most \code{\var{maxsplit}+1}
+elements).
+\versionadded{2.4}
+\end{methoddesc}
+
\begin{methoddesc}[string]{rstrip}{\optional{chars}}
Return a copy of the string with trailing characters removed. If
\var{chars} is omitted or \code{None}, whitespace characters are
diff --git a/Doc/lib/libstring.tex b/Doc/lib/libstring.tex
index 3f902cf..11054e2 100644
--- a/Doc/lib/libstring.tex
+++ b/Doc/lib/libstring.tex
@@ -215,6 +215,23 @@
elements).
\end{funcdesc}
+\begin{funcdesc}{rsplit}{s\optional{, sep\optional{, maxsplit}}}
+ Return a list of the words of the string \var{s}, scanning \var{s} from
+ the end working forward. The resulting list of words is in the same
+ order as \function{split()}. If the optional second argument \var{sep}
+ is absent or \code{None}, the words are separated by arbitrary strings
+ of whitespace characters (space, tab, newline, return, formfeed).
+ If the second argument \var{sep} is present and not \code{None}, it
+ specifies a string to be used as the word separator. The returned
+ list will then have one more item than the number of non-overlapping
+ occurrences of the separator in the string. The optional third argument
+ \var{maxsplit} defaults to 0. If it is nonzero, at most \var{maxsplit}
+ number of splits occur, and the remainder of the string is returned
+ as the first element of the list (thus, the list will have at most
+ \code{\var{maxsplit}+1} elements).
+ \versionadded{2.4}
+\end{funcdesc}
+
\begin{funcdesc}{splitfields}{s\optional{, sep\optional{, maxsplit}}}
This function behaves identically to \function{split()}. (In the
past, \function{split()} was only used with one argument, while