[Python-3000] PEP 3131 accepted

[Ka-Ping Yee]

On Thu, 17 May 2007, Guido van Rossum wrote:
> I have accepted PEP 3131.

I'm surprised that this happened so quickly.  I oppose this proposal
quite strongly.

Currently Python has the property that the character set is a fully
known quantity.  There currently exists a choice of keyboard, a choice
of editor, and a set of literacy skills that is sufficient for any
Python code in the world.

Adopting PEP 3131 destroys this property.  It is not just that
particular communities (e.g. English speakers) will be unable to
understand code by other particular communities (e.g. Japanese
speakers); that is relatively minor and arguably already the case.
The real problem is that it will be impossible for *anyone*, no matter
what their background, to acquire the resources necessary to handle
all Python code.  There will exist no keyboard that enables one to
edit any Python program, and probably no editor.  There will not be a
single human being alive who can know or recognize the whole character
set.  Using APIs in a few different languages would yield a program
that no one could understand.

Today, if a non-English speaker asks you how to learn Python, you can
answer that question.  You can explain Python's syntax and semantics,
and tell them they need to know the 26 letters of the Roman alphabet.
After PEP 3131, you won't be able to answer their question -- because
it will be impossible for any human being to enumerate, let alone
possess, the knowledge required to read an arbitrary piece of Python
code.

PEP 3131 will also cause problems for code review.  Because many
characters have indistinguishable appearances, there will be no
mapping between what you see when you look at code and what the code
actually says.  So it will no longer be possible to look at a piece of
Python code on your screen or on paper and be sure you know what it
means, or even know that it is valid Python syntax.  It will be much
easier to write programs that look right but do the wrong thing, which
is particularly bad if you are concerned with security.

I like the idea that, after studying and working with Python for a
modest amount of time, one can acquire a complete understanding of the
language that affords confidence in the ability to read arbitrary
programs written in Python, make changes to anything written in Python,
and reuse any libraries or modules written in Python.  (It is for the
same reason that Python has a small and limited set of keywords that
Python should have a small character set.)  I don't like how PEP 3131
would not only take such abilities away from me, but remove them from
the realm of possibility altogether.

Of course, nothing stops one from creating a new language (say,
"UniPython") that consists of Python with Unicode identifiers.  One
could even write a translator from UniPython to Python, thus making it
straightforward to run UniPython programs.  But it would be much
better for this to be a separate language that no one is expected to
fully understand, so that Python can remain a language that one *can*
fully understand.


-- ?!ng