From cb8398815150e458b3f977a5bd398e576d325aa3 Mon Sep 17 00:00:00 2001
From: Fred Drake <fdrake@acm.org>
Date: Wed, 28 Mar 2001 21:15:41 +0000
Subject: Added example use of weak references, contributed by Tim Peters.

---
 Doc/lib/libweakref.tex | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/Doc/lib/libweakref.tex b/Doc/lib/libweakref.tex
index 07e6a3b..ca6c08a 100644
--- a/Doc/lib/libweakref.tex
+++ b/Doc/lib/libweakref.tex
@@ -181,6 +181,28 @@ idiom shown above is safe in threaded applications as well as
 single-threaded applications.
 
 
+\subsection{Example \label{weakref-example}}
+
+This simple example shows how an application can use objects IDs to
+retrieve objects that it has seen before.  The IDs of the objects can
+then be used in other data structures without forcing the objects to
+remain alive, but the objects can still be retrieved by ID if they
+do.
+
+% Example contributed by Tim Peters <tim_one@msn.com>.
+\begin{verbatim}
+import weakref
+
+_id2obj_dict = weakref.mapping()
+
+def remember(obj):
+    _id2obj_dict[id(obj)] = obj
+
+def id2obj(id):
+    return _id2obj_dict.get(id)
+\end{verbatim}
+
+
 \subsection{Weak References in Extension Types
             \label{weakref-extension}}
 
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