[Python-3000] PEP 3131 - the details (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Thu May 17 10:51:19 CEST 2007

Some questions I have: is the defined UID set the same as in the referenced appendix?

Yes; it was copied from there.

Is it the same as in Java (and hence Jython)?

No. Not sure whether I can produce a complete list of differences, but some of them are:

Java allows $ in identifiers, the PEP doesn't (as is Python tradition) (more generally: it allows currency symbols in identifiers)
Java allows arbitrary connecting punctuators as the start; the PEP only allows the underscore
Java allows "arbitrary" digits in an identifier. I'm not quite sure what that means: JLS refers to isJavaIdentifierPart, which specifies "a digit" and refers to isLetterOrDigit, which refers to JLS. isDigit gives true if the character NAME contains DIGIT, and the digit is not in the range U+2000..U+2FFF The PEP specifies that digits need to have the Nd class. Comparing these two, it seems that Java allows several characters from the No class, which Python does not allow.
Java allows "ignorable control characters" in identifiers, which Python doesn't allow.

So, in short, it seems that Python's identifier syntax would be strictly more restrictive than Java's.

The same as in .NET (and hence IronPython)?

This kind of research is time consuming; it cost me an hour to come up with above list. Please research it for yourself.

Regards, Martin