Added intern()
diff --git a/Doc/libfuncs.tex b/Doc/libfuncs.tex
index ddb3a91..34d50d0 100644
--- a/Doc/libfuncs.tex
+++ b/Doc/libfuncs.tex
@@ -212,6 +212,19 @@
the backslash convention.
\end{funcdesc}
+\begin{funcdesc}{intern}{string}
+ Enter \var{string} in the table of ``interned'' strings and return
+ the interned string -- which is \var{string} itself or a copy.
+ Interning strings is useful to gain a little performance on
+ dictionary lookup -- if the keys in a dictionary are interned, and
+ the lookup key is interned, the key comparisons (after hashing) can
+ be done by a pointer compare instead of a string compare. Normally,
+ the names used in Python programs are automatically interned, and
+ the dictionaries used to hold module, class or instance attributes
+ have interned keys. Interned strings are immortal (i.e. never get
+ garbage collected).
+\end{funcdesc}
+
\begin{funcdesc}{int}{x}
Convert a number to a plain integer. The argument may be a plain or
long integer or a floating point number. Conversion of floating