Bryan Olson wrote: > Robert Kern wrote: > > from Numeric import * > > A = array([[0, 1], [2, 3], [4, 5]]) > > A[$-1, $-1] > > > > The result of len(A) has nothing to do with the second $. > > I think you have a good observation there, but I'll stand by my > correctness.
len() cannot be used to determine the value of $ in the context of multiple dimensions. > My initial post considered re-interpreting tuple arguments, but > I abandoned that alternative after Steven Bethard pointed out > how much code it would break. Modules/classes would remain free > to interpret tuple arguments in any way they wish. I don't think > my proposal breaks any sane existing code. What it does do is provide a second way to do indexing from the end that can't be extended to multiple dimensions. > Going forward, I would advocate that user classes which > implement their own kind of subscripting adopt the '$' syntax, > and interpret it as consistently as possible. How? You haven't proposed how an object gets the information that $-syntax is being used. You've proposed a syntax and some semantics; you also need to flesh out the pragmatics. > For example, they > could respond to __len__() by returning a type that supports the > "Emulating numeric types" methods from the Python Language > Reference 3.3.7, and also allows the class's methods to tell > that it stands for the length of the dimension in question. I have serious doubts about __len__() returning anything but a bona-fide integer. We shouldn't need to use incredible hacks like that to support a core language feature. -- Robert Kern [EMAIL PROTECTED] "In the fields of hell where the grass grows high Are the graves of dreams allowed to die." -- Richard Harter -- http://mail.python.org/mailman/listinfo/python-list
