Most of the time, this is quite true. One time, however, when it's not easy
is when you're dealing with generating messages which contain other
You have to generate boundary parameters that are long enough and
random enough so that the delimiters won't occur inside the included
body-parts. It's not just the delimiters of enclosed multiparts that
could cause problems. Allowing boundaries to be substrings of
enclosing boundaries does not solve the problem. In fact, I think the
discussion on the list makes it clear that it causes a lot of people
to misunderstand the problem.
As I've mentioned before, allowing boundaries to be substrings of
boundaries of enclosing multiparts breaks a fair amount of deployed
code that was correct per 1341. The 1521 multipart grammar has a
number of problems, which I've pointed out previously.
No more or less than we expect people to write correct parsers for SMTP. So
the answer is "Yes".
SMTP doesn't require large or arbitrary amounts of lookahead in order
to parse correctly.
_.John G. Myers Internet: jgm+(_at_)CMU(_dot_)EDU