show a common usage of detect_encoding
diff --git a/Doc/library/tokenize.rst b/Doc/library/tokenize.rst
index ac6ae36..446d3bb 100644
--- a/Doc/library/tokenize.rst
+++ b/Doc/library/tokenize.rst
@@ -98,7 +98,17 @@
but disagree, a SyntaxError will be raised. Note that if the BOM is found,
``'utf-8-sig'`` will be returned as an encoding.
- If no encoding is specified, then the default of ``'utf-8'`` will be returned.
+ If no encoding is specified, then the default of ``'utf-8'`` will be
+ returned.
+
+ :func:`detect_encoding` is useful for robustly reading Python source files.
+ A common pattern for this follows::
+
+ def read_python_source(file_name):
+ with open(file_name, "rb") as fp:
+ encoding = tokenize.detect_encoding(fp.readline)[0]
+ with open(file_name, "r", encoding=encoding) as fp:
+ return fp.read()
Example of a script re-writer that transforms float literals into Decimal