Some extra comments and docstrings, and a new class (AddressList), all by ESR.
diff --git a/Lib/rfc822.py b/Lib/rfc822.py
index 9631def..ade3506 100644
--- a/Lib/rfc822.py
+++ b/Lib/rfc822.py
@@ -55,6 +55,7 @@
There are also some utility functions here.
"""
+# Cleanup and extensions by Eric S. Raymond <esr@thyrsus.com>
import string
import time
@@ -339,7 +340,12 @@
return self.dict[string.lower(name)]
def __setitem__(self, name, value):
- """Set the value of a header."""
+ """Set the value of a header.
+
+ Note: This is not a perfect inversion of __getitem__, because
+ any changed headers get stuck at the end of the raw-headers list
+ rather than where the altered header was.
+ """
del self[name] # Won't fail if it doesn't exist
self.dict[string.lower(name)] = value
text = name + ": " + value
@@ -438,6 +444,9 @@
To understand what this class does, it helps to have a copy of
RFC-822 in front of you.
+
+ Note: this class interface is deprecated and may be removed in the future.
+ Use rfc822.AddressList instead.
"""
def __init__(self, field):
@@ -687,6 +696,44 @@
return plist
+class AddressList(AddrlistClass):
+ """An AddressList encapsulates a list of parsed RFC822 addresses."""
+ def __init__(self, field):
+ AddrlistClass.__init__(self, field)
+ if field:
+ self.addresslist = self.getaddrlist()
+ else:
+ self.addresslist = []
+
+ def __len__(self):
+ return len(self.addresslist)
+
+ def __str__(self):
+ return string.joinfields(map(dump_address_pair, self.addresslist),", ")
+
+ def __add__(self, other):
+ # Set union
+ newaddr = AddressList(None)
+ newaddr.addresslist = self.addresslist[:]
+ for x in other.addresslist:
+ if not x in self.addresslist:
+ newaddr.addresslist.append(x)
+ return newaddr
+
+ def __sub__(self, other):
+ # Set difference
+ newaddr = AddressList(None)
+ for x in self.addresslist:
+ if not x in other.addresslist:
+ newaddr.addresslist.append(x)
+ return newaddr
+
+def dump_address_pair(pair):
+ """Dump a (name, address) pair in a canonicalized form."""
+ if pair[0]:
+ return '"' + pair[0] + '" <' + pair[1] + '>'
+ else:
+ return pair[1]
# Parse a date field